Android : Handler not working in Android

I' trying to increment a value in TextView when button was clicked and used Handler as below. Its not incrementing the value of i and displaying only 1 after button was clicked

My activity code is as below

public void changeTxt(View view) {

        // invoke handler and call the thread method for every one second

        threadHandler.postDelayed(new Runnable() {

            @Override
            public void run() {
                // TODO Auto-generated method stub
                i = i + 1;
                txtVw.setText(" Number :: " + i);
            }
        }, 0);

    }

Related button layout is

 <Button android:id="@+id/buttn"
    android:layout_width="fill_parent"  
    android:layout_height="50dp"
    android:text="Add Value" 
    android:gravity="center_horizontal"
    android:layout_below="@+id/txtView"
       android:onClick="changeTxt"

       />