[모바일프로그래밍] 10-5 방송 수신자

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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=".MainActivity">

    <TextView
        android:id="@+id/textView1"
        android:layout_width="308dp"
        android:layout_height="215dp"
        android:layout_marginStart="47dp"
        android:layout_marginTop="52dp"
        android:layout_marginEnd="56dp"
        android:text="방송된 내용"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java

package com.example.myapplication;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.BatteryManager;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    TextView myText;

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

        myText = (TextView) findViewById(R.id.textView1);
    }

    public void onResume() {
        super.onResume();

        IntentFilter filter = new IntentFilter();

        filter.addAction(Intent.ACTION_BATTERY_LOW);
        filter.addAction(Intent.ACTION_BATTERY_CHANGED);
        registerReceiver(receiver, filter);
    }

    @Override
    public void onPause() {
        super.onPause();
        unregisterReceiver(receiver);
    }

    BroadcastReceiver receiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) { // 방송이 왔을 때
            String action = intent.getAction();
            Toast.makeText(context, action, Toast.LENGTH_LONG).show();

            myText.setText(action);

            if (action.equals(Intent.ACTION_BATTERY_CHANGED)) {
                int maxvalue = intent.getIntExtra(BatteryManager.EXTRA_SCALE, 0);
                int value = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
                int level = value * 100 / maxvalue;
                myText.setText(action + "\n현재 배터리 레벨 : " + level);
            }
            else if (action.equals(Intent.ACTION_BATTERY_LOW)) {
                myText.setText(action + "\n배터리가 부족한 상황입니다.");
            }
        }
    };
}

AndroidManifest.xml

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

    <uses-permission android:name="android.permission.BATTERY_STATS"></uses-permission>
    <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>

AVD 우측에 ... 버튼을 클릭하면 배터리 상태를 원하는 대로 변경할 수 있음