View not attached to window manager: Although I have preventive code

Question

I keep getting this error but I am not sure why

java.lang.IllegalArgumentException: View not attached to window manager
        at android.view.WindowManagerImpl.findViewLocked(WindowManagerImpl.java:587)
        at android.view.WindowManagerImpl.removeView(WindowManagerImpl.java:324)
        at android.view.WindowManagerImpl$CompatModeWrapper.removeView(WindowManagerImpl.java:151)
        at android.app.Dialog.dismissDialog(Dialog.java:328)
        at android.app.Dialog$1.run(Dialog.java:119)
        at android.app.Dialog.dismiss(Dialog.java:313)

And it happens in this code

    @Override
    protected void onPostExecute(Void result) {
        if(!isFinishing() && dialog.isShowing()){
            dialog.dismiss();  <-------- HERE IT HAPPENS
        }
   }

Any idea why? I am making sure the activity is not finishing and the dialog is showing before dismissal!

Answer 1

This normally happens when the Activity might have finished or in pause state before the AsyncTask is complete. onPause of the Activity set the dialog to null or dismiss it

@Override
protected void onPostExecute(Void result) {
    if(!isPaused && dialog.isShowing()){
        dialog.dismiss();  <-------- HERE IT HAPPENS
    }
}
boolean isPaused;
@Override
protected void onPause() {
    super.onPause();
    isPaused = true;
}
@Override
protected void onResume() {
    super.onResume();
    isPaused = false;
    if(dialog.isShowing() && (asyncFinishedCheck)){
        //Dismiss code goes here
    }
}