[android help] How to kill a PostDelayed Method in Android

I used postedDelayed method to refresh my Activity, which works fine. But the problem is that even when I press the Back button postdelayed method call back the previous activity..

//handler for 30000 milli-secs post delay refreshment of the activity

mHandler.postDelayed(new Runnable() {
public void run() {
               dostuff();

        }
            }, 30000);
    }

protected void dostuff() {
Intent intent = getIntent();
finish();startActivity(intent);
Toast.makeText(getApplicationContext(), "refreshed", Toast.LENGTH_LONG).show();
}

public void onBackPressed() {
        super.onBackPressed();
        finish();
        mHandler.removeCallbacks(null);
        }

protected void onStop() {
            mHandler.removeCallbacks(null);
        super.onStop();
    }

.

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