[ACCEPTED]-NullPointerException on getActivity().runOnUiThread(new Runnable(){-nullpointerexception

Accepted answer

Score: 72

I'm almost sure that this is caused when 4 the thread finish its work but the activity 3 is no longer visible.

You should check if 2 the getActivity() call return null, and ...

To apply corrections 1 on your code, look at this:

// (Calendar) Date function - Displays dateview on Card
final boolean keepRunning1 = true;
Thread thread_two = new Thread(){

@Override
public void run(){

    while(keepRunning1){

        // Make the thread wait half a second. If you want...
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            Toast.makeText(getActivity().getApplicationContext(), "Default Signature                         Fail", Toast.LENGTH_LONG).show();
            e.printStackTrace();
        }

        // here you check the value of getActivity() and break up if needed
        if(getActivity() == null)
            return;

        getActivity().runOnUiThread(new Runnable(){
        @Override
        public void run(){
           TextView date = (TextView) getView().findViewById(R.id.date);
           date.setText(DateUtils.formatDateTime(getActivity().getBaseContext(), System.currentTimeMillis(),DateUtils.FORMAT_SHOW_WEEKDAY | DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_SHOW_YEAR));
           }
         });
    }
}
};thread_two.start();

Score: 21

After pressing back, your background thread 4 is still running. By the time that thread 3 reaches the getActivity().runOnUiThread() code, the activity no longer 2 exists. Check if the activity still exists 1 like so:

if (getActivity() != null) {
        getActivity().runOnUiThread(new Runnable(){
                @Override
                public void run(){
                    TextView date = (TextView) getView().findViewById(R.id.date);
                    date.setText(DateUtils.formatDateTime(getActivity().getBaseContext(), System.currentTimeMillis(),DateUtils.FORMAT_SHOW_WEEKDAY | DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_SHOW_YEAR));
            }
        });
}

Score: 10

Put

if(getActivity() == null)
        return;

before getActivity().runOnUiThread(new Runnable(){ that way when the back button 3 is closed and your Thread is still running it 2 will check whether the calling Activity still exists.

If 1 it does not it will return.

Score: 8

The reason for the NPE is that your thread 6 is not bound to the fragment lifecycle. Once 5 the fragment is detached from its hosting 4 activity, getActivity() returns null.

As a solution, consider 3 removing the thread altogether and just 2 use postDelayed() on a Handler on the UI thread to post Runnables that 1 do the updates you want after a delay.

Score: 5

Try this one

TextView date = (TextView) getView().findViewById(R.id.date);

is date is null or not check 1

if(date !=null){
                    date.setText(DateUtils.formatDateTime(getActivity().getBaseContext(), System.currentTimeMillis(),DateUtils.FORMAT_SHOW_WEEKDAY | DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_SHOW_YEAR));
}

Source: stackoverflow.com

[ACCEPTED]-NullPointerException on getActivity().runOnUiThread(new Runnable(){-nullpointerexception

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