Android 重复通知在应用程序关闭时不起作用

我想每天在特定时间发送通知。打开应用程序时，代码正在运行。但当它关闭并删除时，通知不会显示。我已经为此使用了广播接收器和服务。代码如下。任何人都可以帮助解决这个问题。

清单文件

<receiver
        android:name=".MyReceiver"
        android:enabled="true"
        android:exported="true" />
<service
        android:name=".MyService"
        android:enabled="true"
        android:exported="true" />

MyReceiver.java

public class MyReceiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
    intent = new Intent(context, MyService.class);
    context.startService(intent);
}}

MyService.java

public class MyService extends Service {
@Nullable
@Override
public IBinder onBind(Intent intent) {
    return null;
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    createNotification();
    return Service.START_STICKY;
}

private static final String NOTIFICATION_CHANNEL_ID = "Channel01";
private void createNotification() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        String name =  preferences.getString("name", "User");
        name = name.split(" ")[0];
        String namee = "Remainder";
        String description = "Remainder to update Wallet";
        int importance = NotificationManager.IMPORTANCE_HIGH;

        NotificationChannel notificationChannel = new NotificationChannel(NOTIFICATION_CHANNEL_ID, namee, importance);
        notificationChannel.setDescription(description);

        Intent notifyIntent = new Intent(getApplicationContext(), MainActivity.class);
        PendingIntent pendingIntent = PendingIntent.getActivity(getApplicationContext(), 1, notifyIntent, 0);

        Notification notification = new Notification.Builder(getApplicationContext())
                .setContentTitle("Remainder")
                .setContentText("Hey " + name + ", Let's update your wallet")
                .setSmallIcon(R.drawable.wallet)
                .setChannelId(NOTIFICATION_CHANNEL_ID)
                .setLargeIcon(BitmapFactory.decodeResource(getApplicationContext().getResources(), R.drawable.wallet_new))
                .setContentIntent(pendingIntent)
                .build();

        NotificationManager notificationManager = (NotificationManager)getApplicationContext().getSystemService(Context.NOTIFICATION_SERVICE);
        notificationManager.createNotificationChannel(notificationChannel);
        // Issue the notification.
        notificationManager.notify(1 , notification);
    }
}}

活动.java

Intent notifyIntent = new Intent(getApplicationContext(), MyReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(getApplicationContext(), 1, notifyIntent, 0);
alarmManager = (AlarmManager) getApplicationContext().getSystemService(Context.ALARM_SERVICE);
alarmManager.setInexactRepeating(AlarmManager.RTC_WAKEUP, timeMilli, timeInterval, pendingIntent);

您不应该使用应用程序的任何部分来执行此操作。服务、JobScheduler 或工作管理器迟早会被系统终止，以防止电池耗尽。

在我看来，发送重复通知的最佳方法是使用由外部 cron 作业触发的 firebase 云消息传递（例如 firebase 函数上的 php）。

还要确保发送通知到系统托盘而不是应用程序。为此，请使用 FCM DataMessages。数据消息会传送到系统托盘并始终显示 - 即使服务未运行。