How to know if a dialog is dismissed in Android?

You can use an onDismissListener

http://developer.android.com/reference/android/content/DialogInterface.OnDismissListener.html

public Dialog createDialog() {
    Dialog d = new Dialog(this);
    d.setOnDismissListener(new OnDismissListener() {
        @Override
        public void onDismiss(final DialogInterface arg0) {
            // do something
        }
    });
    return d;
}

If you are using a DialogFragment just override onDismiss()

http://developer.android.com/reference/android/app/DialogFragment.html#onDismiss(android.content.DialogInterface)

@Ken Wolf has a great answer to this question.

Just wanted to add that onDismissListener was only introduced in API 17. If you are trying to support something lower, you can use onCancelListener, which is not as good but covers cases like backButton and tapping outside of the AlertDialog.

http://developer.android.com/reference/android/content/DialogInterface.OnCancelListener.html#onCancel(android.content.DialogInterface)

public Dialog createDialog() {
    Dialog d = new Dialog(this);
    d.setOnCancelListener(new DialogInterface.OnCancelListener() {
        @Override
        public void onCancel(DialogInterface dialog) {
            // do something
        }
    });
}