广播接收器在 Android 8 的前台服务中不起作用

Question

我正在尝试创建一个应用程序，允许用户在设定的时间间隔内或手动使设备静音。我还希望用户能够输入更复杂的规则，例如仅在连接到某个 WiFi 网络、蓝牙设备或进入地理围栏时才使手机静音。但是，在静音模式下，我希望允许用户创建电话仍应响铃的联系人列表。

为此，我创建了一个前台服务，我在其中注册了一个广播接收器。但是，在活动离开前台仅几分钟后，接收器就会停止按时工作并不时更新。

此问题出现在装有 Android 8 的设备（华为/荣耀 7x）中。

注意：我尝试将应用添加到打盹白名单并禁用供应商特定的电池优化，但没有任何改变。

下面是我的代码的 MCVE。每当触发服务中的接收器时，一些 int 值就会增加，然后它们会显示在通知中。在我的设备上，自从活动离开前台几分钟后，值停止增加：

清单权限

<uses-permission android:name="android.permission.READ_PHONE_STATE"/>
<uses-permission android:name="android.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS"/>
<uses-permission android:name="android.permission.BLUETOOTH"/>

清单声明服务

<service android:name=".PhoneService"/>

在 Activity 内部启动 Service

//for the sake of simplicity, I omit the code where runtime permissions are requested
Intent foregroundIntent = new Intent(this, PhoneService.class);
foregroundIntent.putExtra(PhoneService.EXTRA_ACTION, PhoneService.ACTION_START);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    startForegroundService(foregroundIntent);
} else {
    startService(foregroundIntent);
}

服务类

public class PhoneService extends Service {

private static final String NOTIFICATION_CATEGORY = "notification_category";
private static final int NOTIFICATION_REQUEST_CODE = 0;
private static final String CHANNEL_ID = "test_channel";
private static final String CHANNEL_NAME = "test channel";
private static final int NOTIFICATION_ID = 1;
public static final String EXTRA_ACTION = "extra_action";
public static final String ACTION_START = "action_start";
public static final String ACTION_STOP = "action_stop";
private static final int STOP_ID = 2;
private int phoneReceiveCount = 0;
private int btReceiveCount = 0;
BroadcastReceiver phoneReceiver;

@Nullable
@Override
public IBinder onBind(Intent intent) {
    return null;
}

@Override
public void onCreate() {
    super.onCreate();
    final IntentFilter intentFilter = new IntentFilter();
    //adding some filters
    intentFilter.addAction("android.intent.action.PHONE_STATE");
    intentFilter.addAction(BluetoothDevice.ACTION_ACL_CONNECTED);
    intentFilter.addAction(BluetoothDevice.ACTION_ACL_DISCONNECTED);
    this.phoneReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            //update the count and show it in the notification body
            //used only to see if the receiver works
            String action = intent.getAction();
            if (action != null && action.equals("android.intent.action.PHONE_STATE")) {
                phoneReceiveCount++;
            } else if (action != null && (action.equals(BluetoothDevice.ACTION_ACL_CONNECTED)) || action.equals(BluetoothDevice.ACTION_ACL_DISCONNECTED)) {
                btReceiveCount++;
            }
            createNotification(context);
        }
    };
    registerReceiver(phoneReceiver, intentFilter);
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    String action = intent.getStringExtra(EXTRA_ACTION);
    if (action.equals(ACTION_START)) {
        createNotification(this);
    } else if (action.equals(ACTION_STOP)) {
        stopSelf();
    }
    //also tried with START_STICKY
    return START_REDELIVER_INTENT;
}

@Override
public void onDestroy() {
    super.onDestroy();
    unregisterReceiver(phoneReceiver);
}

private void createNotification(Context context) {
    //intent to open app
    Intent entryActivityIntent = new Intent(context, MainActivity.class);
    entryActivityIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
    PendingIntent pendingEntryActivityIntent = PendingIntent.getActivity(context, NOTIFICATION_REQUEST_CODE, entryActivityIntent, PendingIntent.FLAG_UPDATE_CURRENT);
    //intent to stop foreground service
    Intent stopServiceIntent = new Intent(context, PhoneService.class);
    stopServiceIntent.putExtra(PhoneService.EXTRA_ACTION, PhoneService.ACTION_STOP);
    stopServiceIntent.addCategory(NOTIFICATION_CATEGORY);
    PendingIntent pendingStopForeground = PendingIntent.getService(context, STOP_ID, stopServiceIntent, PendingIntent.FLAG_UPDATE_CURRENT);
    //build notification
    NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        NotificationChannel channel = new NotificationChannel(
                CHANNEL_ID,
                CHANNEL_NAME,
                NotificationManager.IMPORTANCE_LOW);
        channel.enableVibration(false);
        channel.enableLights(false);
        notificationManager.createNotificationChannel(channel);
    }
    String contentText = "phoneReceiveCount: " + String.valueOf(phoneReceiveCount) + "\nbtReceiveCount: " + String.valueOf(btReceiveCount);
    NotificationCompat.Builder notificationBuilder =
            new NotificationCompat.Builder(context, CHANNEL_ID)
                    .setColor(ContextCompat.getColor(context, R.color.colorPrimary))
                    .setSmallIcon(R.drawable.ic_service_on)
                    .setContentTitle("This is the title")
                    .setContentText(contentText)
                    .addAction(R.drawable.ic_stop, "Stop", pendingStopForeground)
                    .setStyle(new NotificationCompat.BigTextStyle().bigText(contentText))
                    .setContentIntent(pendingEntryActivityIntent);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN && Build.VERSION.SDK_INT < Build.VERSION_CODES.O) {
        notificationBuilder.setPriority(NotificationCompat.PRIORITY_HIGH);
    }
    startForeground(NOTIFICATION_ID, notificationBuilder.build());
}

}

Answer 1

从 Android 8 开始，后台服务和广播（如广播接收器）有一定的限制，必须在运行时使用 context.registerReceiver 注册。

详细解释请看这个链接：

https://developer.android.com/about/versions/oreo/background#broadcasts

您的目标 SDK 高于 25。降低可能会解决问题，但不建议这样做。请按照文档中的指南和步骤解决问题。