Timertask or Handler

Question

Let's say that I want to perform some action every 10 seconds and it doesn't necessarily need to update the view.

The question is: is it better (I mean more efficient and effective) to use timer with timertask like here:

final Handler handler = new Handler();  TimerTask timertask = new TimerTask() {     @Override     public void run() {         handler.post(new Runnable() {             public void run() {                <some task>             }         });     } }; timer = new Timer(); timer.schedule(timertask, 0, 15000); } 

or just a handler with postdelayed

final Handler handler = new Handler();  final Runnable r = new Runnable() {     public void run()      {         <some task>     } }; handler.postDelayed(r, 15000); 

Also I would be grateful if you could explain when to use which approach and why one of them is more efficient than another (if it actually is).

Answer 1

Handler is better than TimerTask.

The Java TimerTask and the Android Handler both allow you to schedule delayed and repeated tasks on background threads. However, the literature overwhelmingly recommends using Handler over TimerTask in Android (see here, here, here, here, here, and here).

Some of reported problems with TimerTask include:

• Can't update the UI thread
• Memory leaks
• Unreliable (doesn't always work)
• Long running tasks can interfere with the next scheduled event

Example

The best source for all kinds of Android examples that I have seen is at Codepath. Here is a Handler example from there for a repeating task.

// Create the Handler object (on the main thread by default) Handler handler = new Handler(); // Define the code block to be executed private Runnable runnableCode = new Runnable() {     @Override     public void run() {       // Do something here on the main thread       Log.d("Handlers", "Called on main thread");       // Repeat this the same runnable code block again another 2 seconds       handler.postDelayed(runnableCode, 2000);     } }; // Start the initial runnable task by posting through the handler handler.post(runnableCode); 

Related

• Handler vs Timer : fixed-period execution and fixed-rate execution android development