java - 当我的闹钟触发 onReceive() 时，通知未显示

Question

当我的警报管理器触发我的 onReceive() 方法时，我试图弹出通知。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);
   // context.startActivity(notificationIntent);

    mBuilder.setContentIntent(contentIntent);


    // Gets an instance of the NotificationManager service
     notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

    //Android Oreo
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        NotificationChannel channel = new NotificationChannel("notify_001",
                "Channel human readable title",
                NotificationManager.IMPORTANCE_DEFAULT);
        notificationManager.createNotificationChannel(channel);
    }

    // Builds the notification and issues it.
    notificationManager.notify(mNotificationId, mBuilder.build());
}

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，它在创建后 1 分钟后触发，但通知仍然没有显示。

有什么想法吗？

谢谢

Answer 1

来自 Android 开发者:

When you target Android 8.0 (API level 26), you must implement one or more notification channels. If your targetSdkVersion is set to 25 or lower, when your app runs on Android 8.0 (API level 26) or higher, it behaves the same as it would on devices running Android 7.1 (API level 25) or lower.

因为您的targetSdkVersion是28，所以您也必须在Builder构造函数中添加channelId。

将代码更改为:

// Build Notification , setOngoing keeps the notification always in status bar
mBuilder = new NotificationCompat.Builder(context, "notify_001") // Add channel ID to the constructor.
        .setSmallIcon(R.drawable.ic_launcher_foreground)
        .setContentTitle("RandomTitle")
        .setContentText("RandomText")
        .setOngoing(true);