CODEWITHSUNDEEP
androidmultithreading
rex
rex

Reputation: 821

Is this a prefect way to stop handlerthread?

I always create two handler: one is wraping on main thread, another is wraping on a single thread.

Is this a best method to start and stop these in an Activity lifecycle?

HandlerThread safeThread = null;
Handler safeHandler = null;
Handler handler = null;


@Override
    public void onStart() {

if (safeThread == null) {
            safeThread = new HandlerThread("safeThread");
            safeThread.start();
            safeHandler = new Handler(safeThread.getLooper());
        } else if (safeThread.getState() == Thread.State.NEW) {
            safeThread.start();
            safeHandler = new Handler(safeThread.getLooper());
        } else if (safeThread.getState() == Thread.State.WAITING) {
            safeHandler = new Handler(safeThread.getLooper());
        } else if (safeThread.getState() == Thread.State.TERMINATED) {
            safeThread = null;
            safeThread = new HandlerThread("safeThread");
            safeThread.start();
            safeHandler = new Handler(safeThread.getLooper());
        }
}




protected void onStop() {
        Log.d("x", "onStop is executed");
        safeHandler = null;
        safeThread.quit();
        safeThread.interrupt();
        safeThread = null;
        super.onStop();
    }

Upvotes: 18

Views: 26881

Answers (4)

Tofeeq Ahmad
Tofeeq Ahmad

Reputation: 11975

You can use this as a safe way to stop threads:

 if (safeThread!= null) {
     safeThread.quit();
     safeThread = null; // Object is no more required.
 }

You can use safeThread.quitsafely as well.

Upvotes: 1

iammrmehul
iammrmehul

Reputation: 820

I have been following this :

if (safeHandler!= null) {
     final Looper looper = safeHandler.getLooper();
     looper.quitSafely();
     safeHandler = null;
 }

Upvotes: 0

SharkAlley
SharkAlley

Reputation: 11659

If you start the thread like this:

HandlerThread thread = new HandlerThread("MyHandlerThread");
thread.start();

The safest way to stop it would be:

thread.quitSafely();

quitSafely ensures that all pending messages are processed before the thread stops.

Note: My original answer included an additional call to thread.join, but I found the join call does not release reliably when used after quitSafely.

Upvotes: 16

Budius
Budius

Reputation: 39836

I know it's a somewhat old question, but I stumble across it looking for the same answer and further researching I don't believe the current answer applies very well to HandlerThread (although absolutely correct for normal threads)

HandlerThread have a builtin quit() and quitSafely(API18) methods to stop the thread. https://developer.android.com/reference/android/os/HandlerThread.html#quit()

the difference between the two is only if the messages in queue will be processed before it stops or not.

so to answer, it's as simple as: 

safeThread.quit();

Upvotes: 25

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