Short answer: they all run on the same thread. If instantiated from an Activity lifecycle callback, they all run on the main UI thread. Long answer: A thread may have a Looper, which contains a MessageQueue. In order to use this facility, you would have to create a Looper on the current thread by calling … Read more
Because you call postDelayed() again after removing call backs. Please use this code: final Handler handler = new Handler(); final Runnable runnable = new Runnable() { public void run() { Log.d(“Runnable”,”Handler is working”); if(i == 5){ // just remove call backs handler.removeCallbacks(this); Log.d(“Runnable”,”ok”); } else { // post again i++; handler.postDelayed(this, 5000); } } }; … Read more
I have an app which has a feature A which should run in background every minute. That will not happen on hundreds of millions of Android devices, those running Android 6.0 and higher, due to Doze mode (and, possibly, app standby, depending on the rest of your app). But AlarmManager seems to be a good … Read more
You’re almost using postDelayed(Runnable, long) correctly, but just not quite. Let’s take a look at your Runnable. final Runnable r = new Runnable() { public void run() { handler.postDelayed(this, 1000); gameOver(); } }; When we call r.run(); the first thing it’s going to do is tell your handler to run the very same Runnable after … Read more
Here is a real life example where HandlerThread becomes handy. When you register for Camera preview frames, you receive them in onPreviewFrame() callback. The documentation explains that This callback is invoked on the event thread open(int) was called from. Usually, this means that the callback will be invoked on the main (UI) thread. Thus, the … Read more
You should use Handler.post() whenever you want to do operations on the UI thread. So let’s say you want to change a TextView‘s text in the callback. Because the callback is not running on the UI thread, you should use Handler.post(). In Android, as in many other UI frameworks, UI elements (widgets) can be only … Read more
It seems you have imported a wrong Handler class import java.util.logging.Handler; Change it to import android.os.Handler;
You can use: Handler handler = new Handler() handler.postDelayed(new Runnable()) Or you can use: handler.removeCallbacksAndMessages(null); Docs public final void removeCallbacksAndMessages (Object token) Added in API level 1 Remove any pending posts of callbacks and sent messages whose obj is token. If token is null, all callbacks and messages will be removed. Or you could also … Read more
If whatever you are doing is “heavy” you should be doing it in a Thread. If you do not explicitly start it in its own thread, then it will run on the main (UI) thread which may be noticeable as jittery or slow to respond interface by your users. Interestingly when you are using a … Read more
In my experience calling this worked great! handler.removeCallbacksAndMessages(null); In the docs for removeCallbacksAndMessages it says… Remove any pending posts of callbacks and sent messages whose obj is token. If token is null, all callbacks and messages will be removed.