实战Android：通过BroadcastReceiver监听Home，电源Power，和音量变化Volume键

上一个例子是采用AccessibilityService来实现按键的监听。这次我们采用BroadcastReceiver来完成按键的监听。

缺点：我尝试了一下，暂时还不知道如何停止按 键的默认行为，比如我确实监听到了电源按键，但却没法阻止此刻屏幕变黑的行为。先在这记下。以后找到解决办法再补充。

注意点：

1。监听Home键的相关字符串。

注意下边的注释，这几个字符串是Android系统已经内置好了的，必须是这样，比如你写成home_key，就不会反应。

final String SYSTEM_DIALOG_REASON_KEY = "reason";//按下Home键
final String SYSTEM_DIALOG_REASON_HOME_KEY = "homekey"; // 系统内置字符串，表示home键 == 长按Home键
final String SYSTEM_DIALOG_REASON_RECENT_APPS = "recentapps"; // 系统内置字符串，停止键

2。监听Volume键的字符串。

volume键的IntentFilter和Home，Power键不一样，没有相关ACTION，我只找到了这个，确实能监听到音量按键，但假设已经达到最大音量或最小音量，再往极限调，音量不会变化，就监听不到了。

mIntentFilter = new IntentFilter();
mIntentFilter.addAction("android.media.VOLUME_CHANGED_ACTION");

好了，下面先看监听输出，我的手机大致如此，

源码如下，

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.spacesoftwares.spacecapture">
    <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"
            android:launchMode="singleTask">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <service
            android:name=".service.WhiteService"
            android:enabled="true"
            android:exported="false"
            />
    </application>
</manifest>

MainActivity.java

package com.spacesoftwares.spacecapture;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

import com.spacesoftwares.spacecapture.service.WhiteService;


public class MainActivity extends AppCompatActivity {

    private Button mBtnWhite, mBtnStopWhite, mBtnExit;

    private final static String TAG = MainActivity.class.getSimpleName();
    private Intent whiteIntent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mBtnWhite = findViewById(R.id.btn_white);
        mBtnStopWhite = findViewById(R.id.btn_stop_white);
        mBtnExit = findViewById(R.id.btn_exit);
        setListener();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
    }

    class ExitReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            MainActivity.this.finish();
        }
    }

    private void setListener(){
        OnClick onClick = new OnClick();
        mBtnWhite.setOnClickListener(onClick);
        mBtnStopWhite.setOnClickListener(onClick);
        mBtnExit.setOnClickListener(onClick);
    }

    private class  OnClick implements  View.OnClickListener{
        @Override
        public void onClick(View view) {
            int viewId = view.getId();
            switch(viewId){
                case R.id.btn_white:
                    Log.i(TAG, "MAIN: btn_white");
                    if(null == whiteIntent)
                        whiteIntent = new Intent(MainActivity.this, WhiteService.class);
                    startService(whiteIntent);
                    break;
                case R.id.btn_stop_white:
                    Log.i(TAG, "MAIN: btn_stop_white");
                    if(null != whiteIntent)
                       stopService(whiteIntent);
                break;
                case R.id.btn_exit:
                    Log.i(TAG, "MAIN: btn_exit");
                    if(null != whiteIntent)
                        stopService(whiteIntent);
                    finish();
                    break;
            }
        }
    }

}

WhiteService.java

package com.spacesoftwares.spacecapture.service;

import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.os.Build;
import android.os.IBinder;
import android.provider.Settings;
import android.support.annotation.Nullable;
import android.support.v4.app.NotificationCompat;
import android.util.Log;

import com.spacesoftwares.spacecapture.MainActivity;
import com.spacesoftwares.spacecapture.R;
import com.spacesoftwares.spacecapture.key.HomeKeyObserver;
import com.spacesoftwares.spacecapture.key.PowerKeyObserver;
import com.spacesoftwares.spacecapture.key.VolumeKeyObserver;

import java.io.IOException;
import java.nio.channels.Channel;

public class WhiteService extends Service {

    static public boolean isPowerKeyPressed = false;

    private final static String TAG = WhiteService.class.getSimpleName();
    private final static int FOREGROUND_ID = 1000;
    private Notification mNotification;

    /**
     * 参考:
     * 1 https://blog.csdn.net/q445697127/article/details/8432513
     * 2 https://blog.csdn.net/lfdfhl/article/details/9903693
     */
    private HomeKeyObserver mHomeKeyObserver;
    private PowerKeyObserver mPowerKeyObserver;
    private VolumeKeyObserver mVolumeKeyObserver;

    private void init() {
        mHomeKeyObserver = new HomeKeyObserver(this);
        mHomeKeyObserver.setHomeKeyListener(new HomeKeyObserver.OnHomeKeyListener() {
            @Override
            public void onHomeKeyPressed() {
                Log.i(TAG,"----> 按下Home键");
                System.out.println("----> 按下Home键");
            }

            @Override
            public void onHomeKeyLongPressed() {
                Log.i(TAG,"----> 长按Home键");
                System.out.println("----> 长按Home键");
            }
        });
        mHomeKeyObserver.startListen();

        //
        mPowerKeyObserver = new PowerKeyObserver(this);
        mPowerKeyObserver.setPowerKeyListener(new PowerKeyObserver.OnPowerKeyListener() {
            @Override
            public void onPowerKeyPressed() {
                Log.i(TAG,"----> 按下电源键");
                System.out.println("----> 按下电源键");
                isPowerKeyPressed = true;
            }
        });
        mPowerKeyObserver.startListen();

        //
        mVolumeKeyObserver = new VolumeKeyObserver(this);
        mVolumeKeyObserver.setVolumeKeyListener(new VolumeKeyObserver.OnVolumeKeyListener() {
            @Override
            public void onVolumeKeyPressed() {
                Log.i(TAG,"----> 按下电源键");
                System.out.println("----> 按下电源键");
            }
        });
        mVolumeKeyObserver.startListen();
    }

    public WhiteService(){}

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        //return null;
        throw new UnsupportedOperationException("Not yet implemented");
    }

    @Override
    public void onCreate() {
        Log.i(TAG, "WhiteService->onCreate");
        super.onCreate();
        init();
    }

    @Override
    public void onDestroy() {
        Log.i(TAG, "WhiteService->onDestroy");
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
        //if(null !=mNotification)
        {
            stopForeground(Service.STOP_FOREGROUND_REMOVE);
        }

        mHomeKeyObserver.stopListen();
        mPowerKeyObserver.stopListen();
        mVolumeKeyObserver.stopListen();
        super.onDestroy();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        if(null != mNotification){
            Log.i(TAG, "WhiteService->onStartCommand->Notification exists");
            return super.onStartCommand(intent, flags, startId);
        }

        Log.i(TAG, "WhiteService->onStartCommand->Create Notification");
        //NotificationManager manager = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
        //NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        String NOTIFICATION_CHANNEL_ID = "my_channel_id_01";

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationChannel notificationChannel = new NotificationChannel(NOTIFICATION_CHANNEL_ID, "My Notifications", NotificationManager.IMPORTANCE_HIGH);

            // Configure the notification channel.
            notificationChannel.setDescription("Channel description");
            notificationChannel.enableLights(true);
            notificationChannel.setLightColor(Color.RED);
            notificationChannel.setVibrationPattern(new long[]{0, 1000, 500, 1000});
            notificationChannel.enableVibration(true);

            NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
            notificationManager.createNotificationChannel(notificationChannel);
        }

        NotificationCompat.Builder builder = new NotificationCompat.Builder(this, NOTIFICATION_CHANNEL_ID);
        builder.setSmallIcon(R.mipmap.ic_launcher);
        builder.setContentTitle("Foreground");
        builder.setContentText("Text shown on notification bar");
        builder.setContentInfo("Content Info");
        builder.setWhen(System.currentTimeMillis());

        Intent activityIntent = new Intent(this, MainActivity.class);
        PendingIntent pendingIntent = PendingIntent.getActivity(this, 1, activityIntent, PendingIntent.FLAG_UPDATE_CURRENT);
        builder.setContentIntent(pendingIntent);
        mNotification = builder.build();
        startForeground(FOREGROUND_ID, mNotification);
        return super.onStartCommand(intent, flags, startId);
    }
}

HomeKeyOberver.java

package com.spacesoftwares.spacecapture.key;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;

import java.util.Objects;

public class HomeKeyObserver {
    private Context mContext;
    private IntentFilter mIntentFilter;
    private OnHomeKeyListener mOnHomeKeyListener;
    private HomeKeyBroadcastReceiver mHomeKeyBroadcastReceiver;

    public HomeKeyObserver(Context context) {
        this.mContext = context;
    }

    //注册广播接收者
    public void startListen(){
        mIntentFilter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
        mHomeKeyBroadcastReceiver=new HomeKeyBroadcastReceiver();
        mContext.registerReceiver(mHomeKeyBroadcastReceiver, mIntentFilter);
        System.out.println("HomeKey----> 开始监听");
    }

    //取消广播接收者
    public void stopListen(){
        if (mHomeKeyBroadcastReceiver!=null) {
            mContext.unregisterReceiver(mHomeKeyBroadcastReceiver);
            System.out.println("HomeKey----> 停止监听");
        }
    }

    // 对外暴露接口
    public void setHomeKeyListener(OnHomeKeyListener homeKeyListener) {
        mOnHomeKeyListener = homeKeyListener;
    }

    // 回调接口
    public interface OnHomeKeyListener {
        void onHomeKeyPressed();
        void onHomeKeyLongPressed();
    }

    //广播接收者
    class HomeKeyBroadcastReceiver extends BroadcastReceiver{
        final String SYSTEM_DIALOG_REASON_KEY = "reason";
        //按下Home键
        final String SYSTEM_DIALOG_REASON_HOME_KEY = "homekey"; // 系统内置字符串，表示home键
        //长按Home键
        final String SYSTEM_DIALOG_REASON_RECENT_APPS = "recentapps"; // 系统内置字符串，停止键
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (Objects.equals(action, Intent.ACTION_CLOSE_SYSTEM_DIALOGS)) {
                String reason = intent.getStringExtra(SYSTEM_DIALOG_REASON_KEY);
                if (reason != null && mOnHomeKeyListener != null) {
                    if (reason.equals(SYSTEM_DIALOG_REASON_HOME_KEY)) {
                        mOnHomeKeyListener.onHomeKeyPressed();
                    } else if (reason.equals(SYSTEM_DIALOG_REASON_RECENT_APPS)) {
                        mOnHomeKeyListener.onHomeKeyLongPressed();
                    }
                }
            }
        }
    }
}

PowerKeyObserver.java

package com.spacesoftwares.spacecapture.key;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.util.Log;

import java.util.Objects;

public class PowerKeyObserver {
    private String TAG_POWER = "PowerKey";
    private Context mContext;
    private IntentFilter mIntentFilter;
    private OnPowerKeyListener mOnPowerKeyListener;
    private PowerKeyBroadcastReceiver mPowerKeyBroadcastReceiver;
    public PowerKeyObserver(Context context) {
        this.mContext = context;
    }

    //注册广播接收者
    public void startListen(){
        mIntentFilter=new IntentFilter(Intent.ACTION_SCREEN_OFF);
        mPowerKeyBroadcastReceiver=new PowerKeyBroadcastReceiver();
        mContext.registerReceiver(mPowerKeyBroadcastReceiver, mIntentFilter);
        Log.i(TAG_POWER, "PowerKey----> 开始监听");
        System.out.println("PowerKey----> 开始监听");
    }

    //取消广播接收者
    public void stopListen(){
        if (mPowerKeyBroadcastReceiver!=null) {
            mContext.unregisterReceiver(mPowerKeyBroadcastReceiver);
            Log.i(TAG_POWER, "PowerKey----> 停止监听");
            System.out.println("PowerKey----> 停止监听");
        }
    }

    // 对外暴露接口
    public void setPowerKeyListener(OnPowerKeyListener powerKeyListener) {
        mOnPowerKeyListener = powerKeyListener;
    }

    // 回调接口
    public interface OnPowerKeyListener {
        void onPowerKeyPressed();
    }

    //广播接收者
    class PowerKeyBroadcastReceiver extends BroadcastReceiver{
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (Objects.equals(action, Intent.ACTION_SCREEN_OFF)) {
                mOnPowerKeyListener.onPowerKeyPressed();
                //abortBroadcast();
            }
        }
    }
}

VolumeKeyObserver.java

package com.spacesoftwares.spacecapture.key;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.util.Log;

import java.util.Objects;

public class VolumeKeyObserver {
    private String TAG_VOLUME = "VOLUME";
    private Context mContext;
    private IntentFilter mIntentFilter;
    private VolumeKeyObserver.OnVolumeKeyListener mOnVolumeKeyListener;
    private VolumeKeyObserver.VolumeKeyBroadcastReceiver mVolumeKeyBroadcastReceiver;

    public VolumeKeyObserver(Context context) {
        this.mContext = context;
    }

    //注册广播接收者
    public void startListen(){
        //mIntentFilter = new IntentFilter(Intent.ACTION_VOICE_COMMAND);
        mIntentFilter = new IntentFilter();
        mIntentFilter.addAction("android.media.VOLUME_CHANGED_ACTION");
        mVolumeKeyBroadcastReceiver=new VolumeKeyObserver.VolumeKeyBroadcastReceiver();
        mContext.registerReceiver(mVolumeKeyBroadcastReceiver, mIntentFilter);
        System.out.println("VolumeKey----> 开始监听");
    }

    //取消广播接收者
    public void stopListen(){
        if (mVolumeKeyBroadcastReceiver!=null) {
            mContext.unregisterReceiver(mVolumeKeyBroadcastReceiver);
            System.out.println("VolumeKey----> 停止监听");
        }
    }

    // 对外暴露接口
    public void setVolumeKeyListener(VolumeKeyObserver.OnVolumeKeyListener VolumeKeyListener) {
        mOnVolumeKeyListener = VolumeKeyListener;
    }

    // 回调接口
    public interface OnVolumeKeyListener {
        void onVolumeKeyPressed();
    }

    //广播接收者
    class VolumeKeyBroadcastReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (Objects.equals(action, "android.media.VOLUME_CHANGED_ACTION")) {
                Log.i(TAG_VOLUME, "VolumeKey----> 监听到了音量调节");
                System.out.println("VolumeKey----> 监听到了音量调节");
            }
        }
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btn_white"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/service_white" />

    <Button
        android:id="@+id/btn_stop_white"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/stop_white" />   

    <Button
        android:id="@+id/btn_exit"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/exit" />

</LinearLayout>

另外我也上传的完整的代码，可以直接下载运行，

https://download.csdn.net/download/tanmx219/10571550