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@Overridepublic 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 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);