当我的警报触发 onReceive() 时未显示通知

Question

当我的警报管理器触发我的 onReceive() 方法时，我试图弹出一个通知。这就是我所做的

@Override

public void onReceive(Context context, Intent intent) {

    PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);

    PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "YOUR TAG");

    //Acquire the lock

    wl.acquire(10000);

    startNotification(context);

    wl.release();

}

public void setAlarm(Context context){

    AlarmManager am=(AlarmManager)context.getSystemService(Context.ALARM_SERVICE);

    Intent intent = new Intent(context, AlarmManagerBroadcastReceiver.class);

    intent.putExtra(Activity, "MainActivity.class");

    PendingIntent pi = PendingIntent.getBroadcast(context, 0, intent, 0);

    assert am != null;

    am.set(AlarmManager.RTC_WAKEUP, 60000, pi);

}

private void startNotification(Context context){

    // Sets an ID for the notification

    int mNotificationId = 001;

    NotificationManager notificationManager;

    NotificationCompat.Builder mBuilder;

            // Build Notification , setOngoing keeps the notification always in status bar

    mBuilder =

            new NotificationCompat.Builder(context)

                    .setSmallIcon(R.drawable.ic_launcher_foreground)

                    .setContentTitle("RandomTitle")

                    .setContentText("RandomText")

                    .setOngoing(true);

    // Create pending intent, mention the Activity which needs to be

    //triggered when user clicks on notification(StopScript.class in this case)

    Intent notificationIntent = new Intent(context, MainActivity.class);

    notificationIntent.putExtra("extra","Extra Notificacion");

    notificationIntent.addFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT |

            Intent.FLAG_ACTIVITY_SINGLE_TOP);

    PendingIntent contentIntent = PendingIntent.getActivity(context, 0, notificationIntent , PendingIntent.FLAG_UPDATE_CURRENT);

我真的很困惑为什么这个通知没有显示，我已经测试了我的警报，它在创建 1 分钟后触发，但通知仍然没有显示。

有任何想法吗？

Answer 1

来自安卓开发者：当您面向 Android 8.0（API 级别 26）时，您必须实现一个或多个通知渠道。如果您的 targetSdkVersion 设置为 25 或更低，当您的应用在 Android 8.0（API 级别 26）或更高版本上运行时，它的行为与在运行 Android 7.1（API 级别 25）或更低版本的设备上的行为相同。因为你targetSdkVersion是 28，所以你也必须channelId在Builder构造函数中添加。将您的代码更改为：// Build Notification , setOngoing keeps the notification always in status barmBuilder = new NotificationCompat.Builder(context, "notify_001") // Add channel ID to the constructor.        .setSmallIcon(R.drawable.ic_launcher_foreground)        .setContentTitle("RandomTitle")        .setContentText("RandomText")        .setOngoing(true);