How to Remove All Callbacks from a Handler

How to remove all callbacks from a Handler?

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.

Remove callback for handler not work

removeCallbacks(Runnable r):

Remove any pending posts of Runnable r that are in the message queue.

so removeCallbacks(..) only stops pending messages (Runnables) not currently running runnable so if you want to stop currently running Runable then use a Boolean varaible for Stoping Thread when user Exit from your app.

see this post for removeCallbacks not stopping runnable

removeCallbacks() doesn't seems to delete the specified Runnable in Handler

handler.removeCallbacksAndMessages(null);

In the docs for removeCallbacksAndMessages it says...

Remove any pending posts of callbacks and sent messages whose obj is token. If a token is null, all callbacks and messages will be removed.

removeCallbacks only stops pending messages (Runnables). If your runnable has already started, then there's no stopping it (at least not this way).

Alternatively, you can extend the Runnable class and give it some kind of kill switch like this:

public class MyRunnable implements Runnable
{
   public boolean killMe = false;

   public void run()
   {
      if(killMe)
         return;

      /* do your work */
   }

   public void killRunnable()
   {
      killMe = true;
   }
}

This will only prevent it from starting, but you could occasionally check killMe and bail out. If you are looping the runnable (like some kind of background thread) you can say:

while(!killMe) {
   /* do work */
}

Remove callback not working in Handler

The problem is that myFunction removes the callback, then you still call handler.postDelayed to schedule a new one. There are plenty of ways to refactor this. For example:

handler=new Handler();
handler.post(runnable);
public Runnable runnable = new Runnable() {

    @Override
    public void run() {
        boolean reschedule = myFunction(position);
        if(reschedule) {
            handler.postDelayed(runnable,10000);
        }
    }
};
public boolean myFunction(int position)
{
    if(position>10) {
        return false;
    }
    return true;
}

You don't have to remove callbacks on the handler because a new one will not be scheduled in the first place.

How to reuse Android-Handler after removing callbacks

If you want to reuse the handler you have to do:

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.

I hope It helps you!

Stop handler.postDelayed()

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 do like the following:

Handler handler =  new Handler()
Runnable myRunnable = new Runnable() {
public void run() {
    // do something
}
};
handler.postDelayed(myRunnable,zeit_dauer2);

Then:

handler.removeCallbacks(myRunnable);

Docs

public final void removeCallbacks (Runnable r)

Added in API level 1 Remove any pending posts of Runnable r that are
in the message queue.

public final void removeCallbacks (Runnable r, Object token)

Edit:

Change this:

@Override
public void onClick(View v) {
    Handler handler =  new Handler();
    Runnable myRunnable = new Runnable() {

To:

@Override
public void onClick(View v) {
    handler = new Handler();
    myRunnable = new Runnable() { /* ... */}

Because you have the below. Declared before onCreate but you re-declared and then initialized it in onClick leading to a NPE.

Handler handler; // declared before onCreate
Runnable myRunnable;

Android Remove Handler postDelayed Dynamically

mHandler.removeCallbacks(runnable);

will only remove any pending posts of Runnable r that are in the message queue. It will not stop an already running thread. You have to explicitly stop the thread. One way to stop that thread is to use a boolean variable as a flag and run your code inside runnable based on the value of that flag. You can take some hints from https://stackoverflow.com/a/5844433/1320616

How to remove a runnable from a handler object added by postDelayed?

Just use the removeCallbacks(Runnable r) method.

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