stopService() 方法不会停止服务

Question

I was learning foreground services and I created a notification channel to make sure that it keeps the service active. The thing is, the app doesn't stop even when I invoke the stopService method. The notification sure does disappear, but the app is still shown to be running in the Running Apps page of my phone.

In this particular app, I have created a Service that Toasts out Random numbers until the Service is running. The thing is when I press the button to stop, it removes the notification. But the Toasts continue on and on and the app is shown to be in progress in the Running Apps page. Here's the code.

MainActivity.class

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.ContextCompat;

import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    TextView timerTextView;
    private Button startButton;
    private Button stopButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        timerTextView = findViewById(R.id.timerTextView);
        startButton = findViewById(R.id.startButton);
        stopButton = findViewById(R.id.stopButton);

        startButton.setOnClickListener(this);
        stopButton.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        Intent intent = new Intent(getApplicationContext(), MyService.class);

        if(v == startButton)
            ContextCompat.startForegroundService(this, intent);

        if (v == stopButton)
            stopService(intent);
    }
}

MyService.class

import android.app.Notification;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Intent;
import android.os.CountDownTimer;
import android.os.IBinder;
import android.widget.Toast;

import androidx.annotation.Nullable;
import androidx.core.app.NotificationCompat;

import java.util.Random;

import static com.example.servicespractice.NotificationClass.CHANNEL_ID;

public class MyService extends Service {

    Random randomGenerator;


    @Override
    public void onCreate() {
        super.onCreate();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        Intent notificationIntent = new Intent(this, MainActivity.class);
        final PendingIntent pendingIntent = PendingIntent.getActivity(this,0, notificationIntent, 0);

        Notification notification = new NotificationCompat.Builder(getApplicationContext(), CHANNEL_ID)
                .setContentTitle("Example Service")
                .setContentText("Countdown In Progress")
                .setSmallIcon(R.drawable.ic_android)
                .setContentIntent(pendingIntent)
                .build();

        new CountDownTimer(60000, 1000) {
            @Override
            public void onTick(long millisUntilFinished) {
                randomGenerator = new Random();
                Toast.makeText(getApplicationContext(), Integer.toString(randomGenerator.nextInt(1000)), Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onFinish() {
                Toast.makeText(getApplicationContext(), "All Numbers Generated", Toast.LENGTH_SHORT).show();
                onDestroy();
            }
        }.start();

        startForeground(1, notification);
        return START_NOT_STICKY;
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
}

NotificationClass.java

import android.app.Application;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.os.Build;

public class NotificationClass extends Application {
    public static final String CHANNEL_ID = "exampleServiceChannel";

    public void onCreate() {
        super.onCreate();
        createNotificationChannel();
    }

    public void createNotificationChannel(){
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){

            NotificationChannel notificationChannel = new NotificationChannel(
                    CHANNEL_ID,
                    "Example Service Channel",
                    NotificationManager.IMPORTANCE_DEFAULT
            );

            NotificationManager notificationManager = getSystemService(NotificationManager.class);
            notificationManager.createNotificationChannel(notificationChannel);
        }
    }

}

Answer 1

You are stopping the service, but the thread is still executing, you need to stop CountDownTimer , maybe this will work. I suggest that you assign a global variable CountDownTimer timer and in the destroy call timer.cancel();

• Try calling stopSelf();