Is this a prefect way to stop handlerthread?

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.

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.

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();