Android run thread in service every X seconds

Question

I want to create a thread in an Android service that runs every X seconds

I am currently using , but the postdelayed method seems to really lag out my app.

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

    super.onStartCommand(intent, flags, startId);

    startRepeatingTask();

    return startId;
}

private final static int INTERVAL = 20000; //20 milliseconds
Handler m_handler = new Handler();

Runnable m_handlerTask = new Runnable()
{
     @Override 
     public void run() {
         // this is bad
          m_handler.postDelayed(m_handlerTask, INTERVAL);
     }
};

void startRepeatingTask()
{
    m_handlerTask.run(); 
}

void stopRepeatingTask()
{
   m_handler.removeCallbacks(m_handlerTask);
   stopSelf();
}

I want to do a new thread like this:

public void threadRun()
{
    Thread triggerService = new Thread(new Runnable(){
        public void run(){
            Looper.prepare();
            try{
                    //do stuff here?

            }catch(Exception ex){
                    System.out.println("Exception in triggerService Thread -- "+ex);
            }//end catch


        }//end run
    }, "aThread");
    triggerService.start();      

    //perhaps do stuff here with a timer?
    timer1=new Timer();

    timer1.scheduleAtFixedRate(new methodTODOSTUFF(), 0, INTERVAL);
}

I'm not sure the best way to do a background thread to run at a certain interval, insight appreciated!

score 66 · Accepted Answer · answered Nov 22 '11 at 19:53

66

There are number of alternative ways to do this. Personally, I prefer to use ScheduledExecutorService:

ScheduledExecutorService scheduleTaskExecutor = Executors.newScheduledThreadPool(5);

// This schedule a runnable task every 2 minutes
scheduleTaskExecutor.scheduleAtFixedRate(new Runnable() {
  public void run() {
    doSomethingUseful();
  }
}, 0, 2, TimeUnit.MINUTES);

answered Nov 22 '11 at 19:53

yorkw

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hey, I basically did this, I used a TimerTask :) – CQM Nov 22 '11 at 21:41
Hi I use this and it works very well, but how do I stop the task? – Kevin Jun 20 '13 at 09:09
4

@Kevin, use [scheduleTaskExecutor.shutdownNow()](http://developer.android.com/reference/java/util/concurrent/ExecutorService.html#shutdownNow%28%29) – yorkw Jun 20 '13 at 22:05
2

will it run even when the app is closed? – laph Aug 23 '13 at 20:15
3

Beware, [`TimeUnit.MINUTES` is not guaranteed to exist on Android](http://stackoverflow.com/questions/3472423/android-java-util-concurrent-timeunit-convert-milliseconds-to-minutes) – Justin Muller Jan 31 '14 at 16:32
What would you do when the device gets in sleep mode? It won't work. – Ahmad Shahwaiz Jan 12 '17 at 08:01
How to run this Scheduler to run even after the app is closed? – Ramji Seetharaman Mar 24 '18 at 23:58

score 4 · Answer 2 · answered Nov 22 '11 at 17:08

Here is how I run a repeating thread, as you'll see it loops every 1 second. I see no lag with this method.

final Thread t = new Thread(new RepeatingThread());
t.start();

And the class:

import android.os.Handler;

public class RepeatingThread implements Runnable {

    private final Handler mHandler = new Handler();

    public RepeatingThread() {

    }

    @Override
    public void run() { 
        mHandler.postDelayed(this, 1000);       
    }
}

score 3 · Answer 3 · edited Jan 18 '17 at 21:26

MyService.java

public class MyService extends Service {

    public static final int notify = 5000;  //interval between two services(Here Service run every 5 seconds)
    int count = 0;  //number of times service is display
    private Handler mHandler = new Handler();   //run on another Thread to avoid crash
    private Timer mTimer = null;    //timer handling

    @Override
    public IBinder onBind(Intent intent) {
        throw new UnsupportedOperationException("Not yet implemented");
    }

    @Override
    public void onCreate() {
        if (mTimer != null) // Cancel if already existed
            mTimer.cancel();
        else
            mTimer = new Timer();   //recreate new
        mTimer.scheduleAtFixedRate(new TimeDisplay(), 0, notify);   //Schedule task
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mTimer.cancel();    //For Cancel Timer
        Toast.makeText(this, "Service is Destroyed", Toast.LENGTH_SHORT).show();
    }

    //class TimeDisplay for handling task
    class TimeDisplay extends TimerTask {
        @Override
        public void run() {
            // run on another thread
            mHandler.post(new Runnable() {
                @Override
                public void run() {
                    // display toast
                    Toast.makeText(MyService.this, "Service is running", Toast.LENGTH_SHORT).show();
                }
            });

        }

    }
}

MainActivity.java

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        startService(new Intent(this, MyService.class)); //start service which is MyService.java
    }
}

Add following code in AndroidManifest.xml

AndroidManifest.xml

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

The tip here is to use Service and implement a Timer running a TimerTask for an interval. My sample here is that I have Toast and Time in every 5 seconds — Khyati Vara, Dec 28 '16 at 11:12

score 0 · Answer 4 · answered Nov 22 '11 at 17:08

Starting a runnable every few seconds is gonna have some lag no matter what way you slice it, no? I don't see why a Handler shouldn't work just fine.

You might be experiencing some troubles though because you have

void startRepeatingTask()
{
    m_handlerTask.run(); 
}

Instead, you should use the Handler and do something like:

void startRepeatingTask()
{
    m_handler.post(m_handlerTask); 
}

(As an aside, the convention in Java is to use camel case, not snake case. So it should be mHandler, not m_handler, etc. Just telling you because it might make your code easier to read for some.)

I have a way that only starts runnable once, no lag this way — CQM, Nov 22 '11 at 21:42

Android run thread in service every X seconds

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