Some versions of the problems encountered during the development of Android 9.0 and above versions

1. Using the front desk

To add permissions

<uses-permission android:name="android.permission.FOREGROUND_SERVICE" />

Notify part of the code should also be amended

// later android 8.0 new 
        String CHANNEL_ONE_ID = "com.example.servicetest" ;
        String CHANNEL_ONE_NAME = "Channel One";
        NotificationChannel notificationChannel = null;
        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){
            notificationChannel = new NotificationChannel(CHANNEL_ONE_ID,CHANNEL_ONE_NAME, NotificationManager.IMPORTANCE_HIGH);
            notificationChannel.enableLights(true);
            notificationChannel.setLightColor(Color.RED);
            notificationChannel.setShowBadge(true);
            notificationChannel.setLockscreenVisibility(Notification.VISIBILITY_PUBLIC);
            NotificationManager manager = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
            manager.createNotificationChannel(notificationChannel);

            // create the front desk 
            the Intent the Intent = new new the Intent ( the this , MainActivity. Class );
            PendingIntent pi = PendingIntent.getActivity(this,0,intent,0);
            Notification notification = new Notification.Builder(this)
                    .setChannelId(CHANNEL_ONE_ID)//新增
                    .setContentTitle("This is content title")
                    .setContentText("This is content title")
                    .setWhen(System.currentTimeMillis())
                    .setSmallIcon(R.mipmap.ic_launcher)
                    .setContentIntent(pi)
                    .build();
            notification.flags |= Notification.FLAG_NO_CLEAR;//新增
            startForeground(1,notification);
        }