2020.04.16

1. [과제] 계산기 만들기

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textColor="#000000"
        android:text="계 산 기"
        android:gravity="center"
        android:textAppearance="@style/TextAppearance.AppCompat.Display1" />

    <EditText
        android:id="@+id/etResult"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="number"
        android:textColorHint="#000000"
        android:hint="0"
        android:gravity="right" />

    <TableLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center">

        <TableRow
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <Button
                android:id="@+id/btn7"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_margin="3dp"
                android:background="#F3EAA1"
                android:text="7" />

            <Button
                android:id="@+id/btn8"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_margin="3dp"
                android:background="#F3EAA1"
                android:text="8" />

            <Button
                android:id="@+id/btn9"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_margin="3dp"
                android:background="#F3EAA1"
                android:text="9" />

            <Button
                android:id="@+id/btn_div"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_margin="3dp"
                android:background="#5FDAEA"
                android:text="÷" />
        </TableRow>

        <TableRow
            android:layout_width="match_parent"
            android:layout_height="match_parent" >

            <Button
                android:id="@+id/btn4"
                android:layout_width="wrap_content"
                android:layout_height="54dp"
                android:layout_margin="3dp"
                android:background="#F3EAA1"
                android:text="4" />

            <Button
                android:id="@+id/btn5"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:background="#F3EAA1"
                android:layout_margin="3dp"
                android:text="5" />

            <Button
                android:id="@+id/btn6"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_margin="3dp"
                android:background="#F3EAA1"
                android:text="6" />

            <Button
                android:id="@+id/btn_mul"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_margin="3dp"
                android:background="#5FDAEA"
                android:text="X" />
        </TableRow>

        <TableRow
            android:layout_width="match_parent"
            android:layout_height="match_parent" >

            <Button
                android:id="@+id/btn1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_margin="3dp"
                android:background="#F3EAA1"
                android:text="1" />

            <Button
                android:id="@+id/btn2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:background="#F3EAA1"
                android:layout_margin="3dp"
                android:text="2" />

            <Button
                android:id="@+id/btn3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:background="#F3EAA1"
                android:layout_margin="3dp"
                android:text="3" />

            <Button
                android:id="@+id/btn_sub"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:background="#5FDAEA"
                android:layout_margin="3dp"
                android:text="─" />
        </TableRow>

        <TableRow
            android:layout_width="match_parent"
            android:layout_height="match_parent" >

            <Button
                android:id="@+id/btn_del"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_margin="3dp"
                android:background="#B2E17B"
                android:text="C" />

            <Button
                android:id="@+id/btn0"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_margin="3dp"
                android:background="#F3EAA1"
                android:text="0" />

            <Button
                android:id="@+id/btn_et_result"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_margin="3dp"
                android:background="#B2E17B"
                android:text="=" />

            <Button
                android:id="@+id/btn_add"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_margin="3dp"
                android:background="#5FDAEA"
                android:text="+" />
        </TableRow>
    </TableLayout>

</LinearLayout>

package com.lec.android.a003_widget;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class Main2Activity extends AppCompatActivity {

    EditText etResult;
    Button btn0, btn1, btn2, btn3, btn4, btn5, btn6, btn7, btn8, btn9;
    Button btn_div, btn_mul, btn_sub, btn_add;
    Button btn_et_result, btn_del;

    // 피연산자
    String cal1 = "";
    String cal2 = "";

    // 연산자
   String operator;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        etResult = findViewById(R.id.etResult);

        // 숫자
        btn0 = findViewById(R.id.btn0);
        btn1 = findViewById(R.id.btn1);
        btn2 = findViewById(R.id.btn2);
        btn3 = findViewById(R.id.btn3);
        btn4 = findViewById(R.id.btn4);
        btn5 = findViewById(R.id.btn5);
        btn6 = findViewById(R.id.btn6);
        btn7 = findViewById(R.id.btn7);
        btn8 = findViewById(R.id.btn8);
        btn9 = findViewById(R.id.btn9);

        // 연산자
        btn_div = findViewById(R.id.btn_div);
        btn_mul = findViewById(R.id.btn_mul);
        btn_sub = findViewById(R.id.btn_sub);
        btn_add = findViewById(R.id.btn_add);

        // 결과, 지우기
        btn_et_result = findViewById(R.id.btn_et_result);
        btn_del = findViewById(R.id.btn_del);

        btn_et_result.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                cal2 = etResult.getText().toString();
                if(operator.equals("") || cal1.equals("") || cal2.equals("")) {return;}
                double result = 0;

                try {
                    if(operator.equals("+")) {
                        result = Double.parseDouble(cal1) + Double.parseDouble(cal2);
                        etResult.setText(String.valueOf(result));
                    } else if(operator.equals("-")) {
                        result = Double.parseDouble(cal1) - Double.parseDouble(cal2);
                        etResult.setText(String.valueOf(result));
                    } else if(operator.equals("X")) {
                        result = Double.parseDouble(cal1) * Double.parseDouble(cal2);
                        etResult.setText(String.valueOf(result));
                    } else {
                        result = Double.parseDouble(cal1) / Double.parseDouble(cal2);
                        etResult.setText(String.valueOf(result));
                    }

                } catch (Exception e){
                    etResult.setText("");

                } finally {
                    cal1 = "";
                    cal2 = "";
                    operator = "";
                }

            }
        });

        btn_del.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                etResult.setText("");
            }
        });

        // 숫자 버튼 리스너
        class numberListener implements View.OnClickListener {
            @Override
            public void onClick(View v) {
                String text = (String)((Button)v).getText();
                etResult.setText(etResult.getText().append(text));
            }
        }

        // 피연산자 리스너
        class calListener implements View.OnClickListener {
            @Override
            public void onClick(View v) {
                cal1 = etResult.getText().toString();
                operator = (String)((Button)v).getText();
                etResult.setText("");
            }
        }

        btn0.setOnClickListener(new numberListener());
        btn1.setOnClickListener(new numberListener());
        btn2.setOnClickListener(new numberListener());
        btn3.setOnClickListener(new numberListener());
        btn4.setOnClickListener(new numberListener());
        btn5.setOnClickListener(new numberListener());
        btn6.setOnClickListener(new numberListener());
        btn7.setOnClickListener(new numberListener());
        btn8.setOnClickListener(new numberListener());
        btn9.setOnClickListener(new numberListener());
        btn_add.setOnClickListener(new calListener());
        btn_sub.setOnClickListener(new calListener());
        btn_mul.setOnClickListener(new calListener());
        btn_div.setOnClickListener(new calListener());

    } // end onCreate()

} // end Main2Activity

 

** 과제를 하면서 아쉬웠던 점
1) 안드로이드에 익숙하지 못해서 과제를 완수하지 못했음.
   (이번 과정을 통해 처음 안드로이드를 접함)

2) 블로그에 올린 코드는 쌤이 픽한 학생의 코드를 참고하여 작성하여 올림.

** 과제를 하면서 깨달은 점
1) 레이아웃과 액티비티는 연결된다는 점

   (스크린 위에 액티비티가 깔려있고 액티비티 위에 뷰가 깔려 있다는 내용이 이해됨)

2) 레이아웃을 통해 사용자가 볼 수 있는 View가 만들어진다는 점

 

3) 뷰에 다양한 동작이 발생이나 상태 변화가 발생함,

   이러한 이벤트가 발생하면 액티비티를 통해 동작을 심어줄 수 있음

   (이 동작을 심어주기 위해 리스너를 사용한다는 점을 알게 됨)

 

2. a004_widger 모듈

1) Main2Activity 액티비티, activity_main2 레이아웃

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.lec.android.a004_widger">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        
        <activity android:name=".Main2Activity">

        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
        
        </activity>

        <activity android:name=".MainActivity" />
    </application>

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".Main2Activity">

    <EditText
        android:id="@+id/op1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="44dp"
        android:ems="10"
        android:inputType="number" />

    <EditText
        android:id="@+id/op2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="48dp"
        android:ems="10"
        android:inputType="number" />

    <LinearLayout
        android:id="@+id/linearLayout"
        android:layout_width="395dp"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/btnPlus"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="ADD"
            android:textAppearance="@style/TextAppearance.AppCompat.Large" />

        <Button
            android:id="@+id/btnMinus"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="SUB"
            android:textAppearance="@style/TextAppearance.AppCompat.Large" />

        <Button
            android:id="@+id/btnMul"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="MUL"
            android:textAppearance="@style/TextAppearance.AppCompat.Large" />

        <Button
            android:id="@+id/btnDiv"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="DIV"
            android:textAppearance="@style/TextAppearance.AppCompat.Large" />
    </LinearLayout>

    <TextView
        android:id="@+id/tvResult"
        android:layout_width="247dp"
        android:layout_height="57dp"
        android:layout_marginTop="48dp"
        android:text="결과"
        android:textAppearance="@style/TextAppearance.AppCompat.Large" />
</LinearLayout>

package com.lec.android.a004_widger;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import android.graphics.Color;
import android.hardware.TriggerEvent;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class Main2Activity extends AppCompatActivity {

    EditText op1, op2;
    TextView tvResult;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        op1 = findViewById(R.id.op1);
        op2 = findViewById(R.id.op2);
        tvResult = findViewById(R.id.tvResult);

        Button btnPlus = findViewById(R.id.btnPlus);
        Button btnMinus = findViewById(R.id.btnMinus);
        Button btnMul = findViewById(R.id.btnMul);
        Button btnDiv = findViewById(R.id.btnDiv);


        btnPlus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String oper1 = op1.getText().toString();
                String oper2 = op2.getText().toString();

                int a, b;

                if(oper1 != null && !oper1.trim().equals("")){
                    a = Integer.parseInt(oper1);
                } else {
                    a = 0;
                }
                // "".equals(oper2)
                if(oper2 != null && !oper2.trim().equals("")){
                    b = Integer.parseInt(oper2);
                } else {
                    b = 0;
                }

                tvResult.setText((a + b) + "");
                //a + b


            }
        });

        btnMinus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String oper1 = op1.getText().toString();
                String oper2 = op2.getText().toString();

                int a, b;

                if(oper1 != null && !oper1.trim().equals("")){
                    a = Integer.parseInt(oper1);
                } else {
                    a = 0;
                }
                // "".equals(oper2)
                if(oper2 != null && !oper2.trim().equals("")){
                    b = Integer.parseInt(oper2);
                } else {
                    b = 0;
                }

                tvResult.setText((a - b) + "");
                //a - b
            }
        });

        btnMul.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String oper1 = op1.getText().toString();
                String oper2 = op2.getText().toString();

                int a, b;

                if(oper1 != null && !oper1.trim().equals("")){
                    a = Integer.parseInt(oper1);
                } else {
                    a = 0;
                }
                // "".equals(oper2)
                if(oper2 != null && !oper2.trim().equals("")){
                    b = Integer.parseInt(oper2);
                } else {
                    b = 0;
                }

                tvResult.setText((a * b) + "");
                //a * b
            }
        });

        btnDiv.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String oper1 = op1.getText().toString();
                String oper2 = op2.getText().toString();

                int a, b;

                if(oper1 != null && !oper1.trim().equals("")){
                    a = Integer.parseInt(oper1);
                } else {
                    a = 0;
                }
                // "".equals(oper2)
                if(oper2 != null && !oper2.trim().equals("")){
                    b = Integer.parseInt(oper2);
                } else {
                    b = 0;
                }

                tvResult.setText((a / b) + "");
                //a / b
            }
        });


        op1.setOnFocusChangeListener(new View.OnFocusChangeListener() {
            // 포커스 변화가 발생했을때 호출되는 메소드
            // boolean 타입 두번째 매개변수 : 포커스 받은 상태이면 true, 잃은상태면 false
            @Override
            public void onFocusChange(View view, boolean hasFocus) {
                if(hasFocus){   // 포커스 받은 상태에선 yellow 로 배경색 변화
                    view.setBackgroundColor(Color.YELLOW);
                } else {
                    view.setBackgroundColor(Color.parseColor("#00000000"));
                }
            }
        });

        op1.setOnEditorActionListener(new TextView.OnEditorActionListener() {
            // 타이핑 완료 되었을때 호출되는 메소드
            @Override
            public boolean onEditorAction(TextView textView, int i, KeyEvent keyEvent) {
                tvResult.setText("첫번째 숫자 입력완료");
                return false;
            }
        });




    } // end onCreate()
    
} // end Activity

 

2) Main3Activity 액티비티, activity_main3 레이아웃

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.lec.android.a004_widger">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        
        <activity android:name=".Main3Activity">
        
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

        </activity>
        
        <activity android:name=".Main2Activity"></activity>
        <activity android:name=".MainActivity"></activity>
    </application>

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".Main3Activity">

    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="CheckBox"
        android:textAppearance="@style/TextAppearance.AppCompat.Display1" />

    <CheckBox
        android:id="@+id/cb1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="딸기"
        android:textAppearance="@style/TextAppearance.AppCompat.Large" />

    <CheckBox
        android:id="@+id/cb2"
        style="@style/TextAppearance.AppCompat.Large"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="포도" />

    <CheckBox
        android:id="@+id/cb3"
        style="@style/TextAppearance.AppCompat.Large"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="키위" />

    <CheckBox
        android:id="@+id/cb4"
        style="@style/TextAppearance.AppCompat.Large"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="바나나" />

    <Button
        android:id="@+id/btnComplete"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="선택완료" />

    <TextView
        android:id="@+id/tvResult"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="선택결과"
        android:textAppearance="@style/TextAppearance.AppCompat.Large" />


</LinearLayout>

package com.lec.android.a004_widger;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.TextView;

public class Main3Activity extends AppCompatActivity {

    CheckBox cb1, cb2, cb3, cb4;
    TextView tvResult;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main3);

        cb1 = findViewById(R.id.cb1);
        cb2 = findViewById(R.id.cb2);
        cb3 = findViewById(R.id.cb3);
        cb4 = findViewById(R.id.cb4);
        tvResult = findViewById(R.id.tvResult);

        Button btnComplete = findViewById(R.id.btnComplete);

        // 버튼을 클릭하면 체트된 내용들만 결과 출력하기
        btnComplete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String result = "";
                if(cb1.isChecked()) {result += cb1.getText();}
                if(cb2.isChecked()) {result += cb2.getText();}
                if(cb3.isChecked()) {result += cb3.getText();}
                if(cb4.isChecked()) {result += cb4.getText();}
                tvResult.setText("선택결과: " + result);
            }
        });

        cb1.setOnCheckedChangeListener(new CbListener());
        cb2.setOnCheckedChangeListener(new CbListener());
        cb3.setOnCheckedChangeListener(new CbListener());
        cb4.setOnCheckedChangeListener(new CbListener());


    } // end onCreate()

    class CbListener implements CompoundButton.OnCheckedChangeListener {

        // CheckBox 의 '상태'가 변할때마다 호출되는 메소드
        // isChecked : true <- 체크된 상태, false <- uncheck 상태
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            int count = 0;
            if(cb1.isChecked()) {count++;}
            if(cb2.isChecked()) {count++;}
            if(cb3.isChecked()) {count++;}
            if(cb4.isChecked()) {count++;}

            tvResult.setText(count + " 개 선택");
        }
    }



} // end Main3Activity

 

3) Main4Activity 액티비티, activity_main4 레이아웃

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.lec.android.a004_widger">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        
        <activity android:name=".Main4Activity">
        
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
            
        </activity>
        
        <activity android:name=".Main3Activity" />
        <activity android:name=".Main2Activity" />
        <activity android:name=".MainActivity" />
    </application>

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".Main4Activity">

    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="RadioButton"
        android:textAppearance="@style/TextAppearance.AppCompat.Display1" />

    <RadioGroup
        android:id="@+id/rg"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <RadioButton
            android:id="@+id/radio1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="국어" />

        <RadioButton
            android:id="@+id/radio2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="영어" />

        <RadioButton
            android:id="@+id/radio3"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="수학" />

        <RadioButton
            android:id="@+id/radio4"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="과학" />

    </RadioGroup>

    <Button
        android:id="@+id/btnResult"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="선택완료" />

    <TextView
        android:id="@+id/tvResult"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="결과창"
        android:textAppearance="@style/TextAppearance.AppCompat.Large" />
</LinearLayout>

package com.lec.android.a004_widger;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;

public class Main4Activity extends AppCompatActivity {

    RadioGroup rg;
    Button btnResult;
    TextView tvResult;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main4);

        // 체크박스와는 달리
        // RadioButton 은 각각 선언하는 것이 아니라
        // RadioGroup 으로 선언하여 사용

        // 여기서 shift + F6을 이용하여 이름 변경하면
        // 모든 이름이 변경됨. 레이아웃, java 파일 전부..!!
        rg = findViewById(R.id.rg);
        btnResult = findViewById(R.id.btnResult);
        tvResult = findViewById(R.id.tvResult);

        btnResult.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // 선택된 라디오 버튼의 id 값 가져오기
                int id = rg.getCheckedRadioButtonId();

                // 위 id 값을 통해 RadioButton 객체 가져오기
                RadioButton rb = findViewById(id);

                tvResult.setText("결과: " + rb.getText());
            }
        });

        // 라디오 버튼을 선택했을 때도 위와 같은 동작하게 하기
        rg.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            // checkedId : 선택된 라디오버튼의 id
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                RadioButton rb = findViewById(checkedId);
                tvResult.setText("결과: " + rb.getText());

            }
        });
    }
}

 

 

3. 사진 추가하기

 : res > drawable 클릭 > 원하는 사진을 복사(Ctrl + C)한 상태에서 붙여넣기(Ctrl + V)
> choose Destination Directory 팝업 창 뜸 > v-24로 끝나는 경로 선택 > OK 클릭(둘중에 어떤것을 해도 무방함)

> 다시 한 번 경로 확인 후 OK 클릭 > 사용할 사진 다운 받기 끝..!!

 

 

4. a005_image 모듈

1) MainActivity 액티비티, activity_main 레이아웃

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.lec.android.a005_image">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name=".MainActivity">

        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>

        </activity>

    </application>

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="@style/TextAppearance.AppCompat.Display1"
        android:text="ImageView"/>

    <TextView
        android:id="@+id/tvResult"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="이미지를 탭하면 다음이미지로 넘어갑니다"/>

    <ImageView
        android:id="@+id/iv1"
        android:layout_width="match_parent"
        android:layout_height="268dp"
        android:layout_weight="0.56"
        android:src="@drawable/a6"
        />

</LinearLayout>

package com.lec.android.a005_image;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

// 안드로이드 의 모든 리소스(Resource) 로 사용하는 파일 들은
// 파일명 규칙
// - 대문자 불가
// - 숫자 시작 불가
// - 공백, 특수문자 불가
// - 특수문자는 _(언더바)만 가능
public class MainActivity extends AppCompatActivity {

    int[] imageId = {R.drawable.a1, R.drawable.a2, R.drawable.a3,
            R.drawable.a4, R.drawable.a5, R.drawable.a6};
    ImageView iv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        iv = findViewById(R.id.iv1);

        // res/drawable 폴더에 있는 이미지로 세팅하기
        iv.setImageResource(R.drawable.a1);

        iv.setOnClickListener(new MyListener());


    } // end onCreate()

    class MyListener implements View.OnClickListener {

        int i = 0;
        TextView tvResult = findViewById(R.id.tvResult);

        @Override
        public void onClick(View v) {
            i++;
            if(i == imageId.length) {i = 0;}

            iv.setImageResource(imageId[i]);
            tvResult.setText("이미지뷰: " + i);

        }
    }

} // end Activity

 

2) Main2Activity 액티비티, activity_main2 레이아웃

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.lec.android.a005_image">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name=".Main2Activity">

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

        </activity>

        <activity android:name=".MainActivity" />
    </application>

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".Main2Activity"
    android:orientation="vertical">

    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="ImageView 표현하는 방법들"
        android:textAppearance="@style/TextAppearance.AppCompat.Display1"/>

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <ImageView
                android:id="@+id/iv1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:src="@mipmap/ic_launcher"/>

            <ImageView
                android:id="@+id/iv2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                app:srcCompat="@android:drawable/btn_star_big_on" />

            <ImageView
                android:id="@+id/iv3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                app:srcCompat="@android:drawable/ic_menu_camera" />

        </LinearLayout>



    </ScrollView>


</LinearLayout>

package com.lec.android.a005_image;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.ContextCompat;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.widget.ImageView;

public class Main2Activity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        ImageView iv1 = findViewById(R.id.iv1);
        ImageView iv2 = findViewById(R.id.iv2);
        ImageView iv3 = findViewById(R.id.iv3);

        // 방법1. 프로젝트 내의 res/drawable 폴더에 있는 파일을 보여주는 방법
        iv1.setImageResource(R.drawable.a2);

        // 방법2. Drawable 객체를 이용해서 보여주는 방법
        //Drawable drawable = getResources().getDrawable(R.drawable.a3);  // minSdkVersion 28로 변경하면 deprecated 됨.
        Drawable drawable = ContextCompat.getDrawable(getApplicationContext(), R.drawable.a3);
                // ContextCompat : API 23부터 추가

        iv2.setImageDrawable(drawable);

        // 방법3 bitmap 객체를 이용해서 보여주는 방법
        Bitmap bm = BitmapFactory.decodeResource(getResources(), R.drawable.a4);
        iv3.setImageBitmap(bm);
    } // end onCreate()

} // end Activity

 

3) Main3Activity 액티비티, activity_main3 레이아웃

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.lec.android.a005_image">
    <!-- 권한 명시 -->
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

    <!-- 안드로이드 10.0 (Q, API29) 부터 발생하는 문제
        https://developer.android.com/training/data-storage#scoped-storage
    -->
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme"
        android:requestLegacyExternalStorage="true">
        <activity android:name=".Main4Activity" />

        <activity android:name=".Main3Activity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity android:name=".Main2Activity"></activity>
        <activity android:name=".MainActivity" />
    </application>

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="폰사진 ImageView 보이기"
        android:textAppearance="@style/TextAppearance.AppCompat.Display1" />

    <Button
        android:id="@+id/btnAction"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="사진 가져오기" />

    <TextView
        android:id="@+id/tvPath"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="사진경로" />

    <ImageView

        android:id="@+id/ivPhoto"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="0.63"
        android:src="@mipmap/ic_launcher" />
</LinearLayout>

package com.lec.android.a005_image;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import android.Manifest;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.Arrays;

/**
 * 폰의 저장장치에 있는 사진을 ImageView 에 띄우기
 *    1. 권한 획득
 *        - 메니페스트
 *        - '위험권한'요청  (Android 6.0 / API23 이상)
 *         https://developer.android.com/guide/topics/security/permissions?hl=ko  (위험권한및 위험권한 목록들)
 *            https://developer.android.com/training/permissions/requesting?hl=ko#java
 *
 *            설치 앱별 '권한' 확인 가능하다 :
 *                픽셀2 폰의 경우 '앱' 아이콘 롱클릭후 App Info 확인
 *
 *    2. 이미지 경로
 *    3. Bitmap 사용하여 ImageView 에 띄우기
 */

public class Main3Activity extends AppCompatActivity {

    ImageView ivPhoto;
    TextView tvPath;
    Button btnAction;

    // 이미지 경로 알아내기 (제조사, 모델마다 다를 수 있다)
    // 픽셀폰 : 갤러리 이미지보기 -> 하단의 i 버튼
    // 삼성폰 : 갤러리 이미지 롱클릭 후 상세정보 ...
    private String imgPath = "/storage/emulated/0/DCIM/Camera/france.png";

    private final int PERMISSION_REQUEST_CODE = 101;    // 권한 요청 코드값(int)
    private final String[] PERMISSIONS = {    // 요청할 권한들을 String[] 로 준비
        Manifest.permission.READ_EXTERNAL_STORAGE,
        Manifest.permission.WRITE_EXTERNAL_STORAGE
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main3);

        ivPhoto = findViewById(R.id.ivPhoto);
        btnAction = findViewById(R.id.btnAction);
        tvPath = findViewById(R.id.tvPath);

        btnAction.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                drawPhoto();  // 위험권한 획득 없이 실행하면?  아래 Exception 발생
                // E/BitmapFactory: Unable to decode stream: java.io.FileNotFoundException: /storage/emulated/0/DCIM/Camera/france.png: open failed: EACCES (Permission denied)
            }
        });

        // '위험권한' 획득
        // API 23(마시멜로) 이상에서만 권한 요청
        // 권한을 획득하지 않은 상태에서만 요청
        //if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        //   if(ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)
        //           != PackageManager.PERMISSION_GRANTED) {
        // 위의 코드를 if 문 두개로 나눌 것이 아니라 &&(AND)를 통해 한번에 조건 기재하기..!!
        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)
                != PackageManager.PERMISSION_GRANTED){

            // 권한 요청 : 비동기로 진행됨.
            ActivityCompat.requestPermissions(this,
                    PERMISSIONS, // 요청할 위험권한(들)
                    PERMISSION_REQUEST_CODE   // 권한 요청 코드
            );

        } else {
            // 권한을 이미 획득한 상태
            drawPhoto();
        }

    } // end onCreate()

    public void drawPhoto(){
        // ImageView <- Bitmap <-경로
        Bitmap bm = BitmapFactory.decodeFile(imgPath);
        ivPhoto.setImageBitmap(bm);
        tvPath.setText(imgPath);
    } // end drawPhoto()


    // 권한 획득 결과 처리 콜백
    // requestCode : 권한 요청 코드 값
    // permissions : 권한 요청 (들)
    // grantResults : 승인 내역 (들)
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        switch (requestCode){
            case PERMISSION_REQUEST_CODE:
                if(grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){
                    // 사용자가 권한 승인함!
                    drawPhoto();

                    Log.d("myapp", "권한획득결과\n\t" + Arrays.toString(permissions) + " : " + Arrays.toString(grantResults));
                } else {
                    // 사용자가 권한 승인 안함!

                }
                break;
        }



    }

} // end Activity

 

[추가] 프로젝트 별로 Gradle 파일 생기고 각 모듈별로 Gradle 파일 생긴다.

         현재 1개의 프로젝트 Gradle 파일과 5개의 모듈 Gradle 파일이 있다.

 

[추가] gradle 파일 수정한 뒤에는 무조건 Sync Now를 해야 함...!!

         minSdkVersion을 21 -> 28로 변경(이전 단말기 중 지원하는 최소 버전을 21 -> 28로 변경)

[추가] AVD 에 저장된 사진 확인하기

 : View > Tool Windows > Device File Explorer 클릭 

> sdcard > DCIM > Camera 클릭

> 현재 AVM에 저장된 사진을 볼 수 있다(현재 저장된 5개의 사진은 AVD기기를 통해 찍은 사진들)

> Camera 선택 후 우클릭 > Upload 클릭 > 다운로드 원하는 파일 선택 후 OK 클릭

> 정상적으로 파일 다운로드 완..!!

> AVD 기기의 Google Photos에서 다운로드한 파일들을 확인 할 수 있다..!!

 

4) Main4Activity 액티비티, activity_main4 레이아웃

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.lec.android.a005_image">
    <!-- 권한 명시 -->
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        
        <activity android:name=".Main4Activity">
        
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

        </activity>
        
        <activity android:name=".Main3Activity" />
        <activity android:name=".Main2Activity" />
        <activity android:name=".MainActivity" />
    </application>

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="인터넷 이미지 보기"
        android:textAppearance="@style/TextAppearance.AppCompat.Display1" />

    <TextView
        android:id="@+id/tvUrl"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="URL"
        android:textAppearance="@style/TextAppearance.AppCompat.Medium" />

    <ImageView
        android:id="@+id/iv1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="0.64"
        android:src="@drawable/abc_btn_check_to_on_mtrl_000" />

</LinearLayout>

package com.lec.android.a005_image;

import androidx.appcompat.app.AppCompatActivity;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Handler;
import android.widget.ImageView;
import android.widget.TextView;

import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;

/**
 *  인터넷 상의 이미지 보여주기
 *      1. 권한을 획득한다 (인터넷에 접근할수 있는 권한을 획득한다)  - 메니페스트 파일
 *      2. Thread 에서 웹의 이미지를 받아온다 - honeycomb(3.0) 버젼 부터 바뀜
 *      3. 외부쓰레드에서 메인 UI에 접근하려면 Handler 를 사용해야 한다.
 *
 */

public class Main4Activity extends AppCompatActivity {

    // 이미지 URL, 반드시 https:// 이어야 한다..!!
    String imgUrl = "https://developer.android.com/studio/images/studio-icon-stable.png";

    ImageView iv1;
    TextView tvUrl;

    Handler handler = new Handler();    // 외부쓰레드에서 메인 UI 화면에 그릴 때 사용

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main4);

        iv1 = findViewById(R.id.iv1);
        tvUrl = findViewById(R.id.tvUrl);


        // [이 부분은 안드로이드에서 추가됨, Bitmap] <- InputStream <- URL <- "url"
        Thread t = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    // Thread 없이 수행하면
                    // android.os.NetworkOnMainThreadException 발생
                    URL url = new URL(imgUrl);
                    InputStream in = url.openStream();
                    final Bitmap bm = BitmapFactory.decodeStream(in);

                    // Handler 없이 사용하면
                    // CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views. 발생
                    //iv1.setImageBitmap(bm);

                    handler.post(new Runnable() {
                        @Override
                        public void run() {
                            // 외부쓰레드에서 메인 UI에 접근할 때는
                            // 반드시 Handler 객체 사용.
                            iv1.setImageBitmap(bm);
                            tvUrl.setText(imgUrl);
                        }
                    });

                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
        t.start();

    } // end onCreate()

} // end Activity

 

 

5. A006_Widget2 모듈

1) MainActivity 액티비티, activity_main 레이아웃

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.lec.android.a006_widget2">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        
        <activity android:name=".MainActivity">

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
            
        </activity>
        
    </application>

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="ProgressBar"
        android:textAppearance="@style/TextAppearance.AppCompat.Display1" />

    <ProgressBar
        android:id="@+id/pb1"
        style="?android:attr/progressBarStyle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <ProgressBar
        android:id="@+id/pb2"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <ToggleButton
        android:id="@+id/toggleButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textOn="보이기"
        android:textOff="숨기기" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="막대프로그래스바" />

    <ProgressBar
        android:id="@+id/pb3"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

package com.lec.android.a006_widget2;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.ProgressBar;
import android.widget.ToggleButton;

public class MainActivity extends AppCompatActivity {

    ProgressBar pb1, pb2, pb3;

    int value = 0;  // 막대프로그래스 바의 현재 진행값
    int add = 10;   // 증가량

    int value2 = 0;
    int add2 = 1;

    Handler handler = new Handler();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        pb1 = findViewById(R.id.pb1);
        pb2 = findViewById(R.id.pb2);
        pb3 = findViewById(R.id.pb3);

        ToggleButton btn1 = findViewById(R.id.toggleButton);
        Button btn2 = findViewById(R.id.button1);

        // 토글버튼 상태 변화시 호출되는 콜백
        btn1.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if(isChecked) {
                    pb1.setVisibility(View.INVISIBLE);
                } else {
                    pb1.setVisibility(View.VISIBLE);
                }
            }
        });

        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                value = value + add;
                if(value > 100 || value < 0) {
                    value = -100;
                }
                pb2.setProgress(value); // 프로그레스 바의 진행값 설정
            }
        });

        // 앱 시작시 Thread를 사용하여 ProgressBar 증가시키기
        Thread t = new Thread(new Runnable() {
            @Override
            public void run() {
                while(true) {

                    value2 = value2 + add2;

                    if(value2 > 100 || value2 < 0) {
                        add2 = -add2;
                    }

                    // 별도의 작업 Thread 에서
                    // 메인 UI에 접근하려면 반드시 Handler 사용해야 함..!!
                    handler.post(new Runnable() {
                        @Override
                        public void run() {
                            pb3.setProgress(value2);
                        }
                    });

                    try {
                        Thread.sleep(100);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        });
        t.start();

    } // end onCreate()

} // end Activity

 

2) Main2Activity 액티비티, activity_main2 레이아웃

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.lec.android.a006_widget2">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        
        <activity android:name=".Main2Activity">

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

        </activity>
        
        <activity android:name=".MainActivity" />
    </application>

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".Main2Activity">

    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Spinner"
        android:textAppearance="@style/TextAppearance.AppCompat.Display1" />

    <TextView
        android:id="@+id/tvResult"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="선택값" />

    <Spinner
        android:id="@+id/spinner1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:entries="@array/city"/>
    
</LinearLayout>

package com.lec.android.a006_widget2;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;

public class Main2Activity extends AppCompatActivity {

    TextView tvResult;
    Spinner spinner1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        tvResult = findViewById(R.id.tvResult);
        spinner1 = findViewById(R.id.spinner1);

        // 아이템을 선택했을때 호출되는 콜백
        spinner1.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

            // 아이템을 선택했을때
            // position : 몇번째 item 인지, 0 ~
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                tvResult.setText("position: " + position + parent.getItemAtPosition(position));
                Toast.makeText(getApplicationContext(), (String)parent.getItemAtPosition(position), Toast.LENGTH_LONG).show();
            }

            // 선택한거 없이 화면에서 사라질때
            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                Toast.makeText(getApplicationContext(), "선택 안했어요", Toast.LENGTH_LONG).show();
            }
        });

    } // end onCreate()

} // end Activity

 

** 안드로이드 문자열 배열 리소스 추가하기
 : res 선택 value 폴더 클릭 > 우클릭 > New > Values Resource File 클릭

> File name 설정 후 OK

> 필요한 문자열 배열 만들기...!!

 

3) Main3Activity 액티비티, activit_main3 레이아웃

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.lec.android.a006_widget2">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name=".Main3Activity">

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

        </activity>

        <activity android:name=".Main2Activity" />
        <activity android:name=".MainActivity" />
    </application>

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".Main3Activity">

    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="SeekBar"
        android:textAppearance="@style/TextAppearance.AppCompat.Display1" />

    <TextView
        android:id="@+id/tvResult"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="진행값"
        android:textAppearance="@style/TextAppearance.AppCompat.Large" />

    <SeekBar
        android:id="@+id/seekBar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:max="200"
        android:progress="50"
        android:thumb="@mipmap/ic_launcher"/>
</LinearLayout>

package com.lec.android.a006_widget2;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.os.Handler;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;

public class Main3Activity extends AppCompatActivity {

    TextView tvResult;
    SeekBar seekBar;

    int value = 0;
    int add = 2;

    Handler handler = new Handler();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main3);

        tvResult = findViewById(R.id.tvResult);
        seekBar = findViewById(R.id.seekBar);

        seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {

            // 값의 변화가 생겼을때 콜백
            // progress : 진행값   0 ~ max
            // fromUer : 사용자에 의한 진행값 변화인 경우 true
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                tvResult.setText("onProgressChanged:" + progress + "(" + fromUser + ")");
            }

            // tracking 시작할때 콜백
            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
                Toast.makeText(getApplicationContext(), "트래킹시작", Toast.LENGTH_SHORT).show();
            }

            // tracking 끝날때 콜백
            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
                Toast.makeText(getApplicationContext(), "트래킹종료", Toast.LENGTH_SHORT).show();
            }
        });

        // 앱 시작시 Thread .. SeekBar 증가 시키기
        new Thread(new Runnable() {

            @Override
            public void run() {

                int max = seekBar.getMax();

                while(true){
                    value = seekBar.getProgress() + add;

                    if(value > max || value < 0){
                        add = -add;
                    }

                    handler.post(new Runnable() {
                        @Override
                        public void run() {
                            seekBar.setProgress(value);
                        }
                    });

                    try {
                        Thread.sleep(100);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }).start();

    } // end onCreate()


} // end Activity