如何在 Android 中显示来自后台服务的推送通知 O // 如何正确使用 startForeground()

Question

我正在尝试显示由 GCM 消息触发的推送通知。 GCM 消息由后台的广播接收器接收，但未显示推送通知。

出于演示目的，我缩小了我的代码：

BroadcastReceiver（日志记录告诉我调用了 onReceive()）

public class GcmBroadcastReceiver extends BroadcastReceiver {
    private static final String TAG = GcmBroadcastReceiver.class.getName();

    @RequiresApi(api = Build.VERSION_CODES.O)
    @Override
    public void onReceive(Context context, Intent intent) {
        Log.d(TAG, "received GCM intent: "+intent.toString());
        ComponentName comp = new ComponentName(context.getPackageName(), GcmIntentService.class.getName());
        context.startForegroundService(intent.setComponent(comp));
    }
}

应该触发通知的 Intent。日志显示调用了 onHandleIntent()。

@RequiresApi(api = Build.VERSION_CODES.O)
public class GcmIntentService extends IntentService {
    private static final String TAG = GcmIntentService.class.getName();

    public GcmIntentService() { super("GcmIntentService"); }

    @Override
    protected void onHandleIntent(Intent intent) {
        Log.d(TAG,"received intent");
        String channelId = "MyChannelId";
        Notification notification = new NotificationCompat.Builder(getApplication(), channelId)
                .setSmallIcon(R.drawable.ic_launcher)
                .setContentTitle("MyTitle")
                .setContentText("MyText")
                .build();

        NotificationChannel channel = new NotificationChannel(channelId, "foo", NotificationManager.IMPORTANCE_HIGH);
        NotificationManager manager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        manager.createNotificationChannel(channel);

        startForeground(1, notification);
        manager.notify(1, notification);
    }
}

我的AndroidManifest.xml:

    <receiver
        android:name=".cdmclient.GcmBroadcastReceiver"
        android:permission="com.google.android.c2dm.permission.SEND" >
        <intent-filter>
            <action android:name="com.google.android.c2dm.intent.RECEIVE" />
            <action android:name="com.google.android.c2dm.intent.REGISTRATION" />
            <category android:name="${applicationId}.cdmclient" />
        </intent-filter>
    </receiver>

    <service android:name=".cdmclient.GcmIntentService" android:exported="false"/>

当应用程序在前台接收到 GCM 事件时，日志显示：

D/de.locked.bob.cdmclient.GcmBroadcastReceiver: received GCM intent: Intent { act=com.google.android.c2dm.intent.RECEIVE flg=0x1000010 pkg=de.locked.bob.debug cmp=de.locked.bob.debug/de.locked.bob.cdmclient.GcmBroadcastReceiver (has extras) }
D/de.locked.bob.cdmclient.GcmIntentService: received intent
E/EnhancedIntentService: binding to the service failed

当应用程序在后台接收到 GCM 事件时，日志显示：

D/de.locked.bob.cdmclient.GcmBroadcastReceiver: received GCM intent: Intent { act=com.google.android.c2dm.intent.RECEIVE flg=0x1000010 pkg=de.locked.bob.debug cmp=de.locked.bob.debug/de.locked.bob.cdmclient.GcmBroadcastReceiver (has extras) }
D/de.locked.bob.cdmclient.GcmIntentService: received intent
W/EnhancedIntentService: Service took too long to process intent: com.google.android.c2dm.intent.RECEIVE App may get closed.

当然，没有显示任何通知。我想我使用 startForeground(..) 和 startForegroundService(...) 的方式不对，但我目前没有想法。

Answer 1

IntentServices 不应该作为前台服务启动（参考：Using startForeground() with an Intent Service）

当推送通知从 GCM 到达时，您是否打算启动服务？您不需要该服务来显示通知；您可以像在服务中那样从 BroadcastReceiver 执行此操作。

如何在 Android 中显示来自后台服务的推送通知 O // 如何正确使用 startForeground()

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