Android programing

   public void main_function()
    {
        final EditText ET1 = (EditText) findViewById(R.id.editText1);
        final EditText ET2 = (EditText) findViewById(R.id.editText2);
        Button BTN =  (Button) findViewById(R.id.btn_Button1);

       BTN.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View v) {
               ET1.setText(ET2.getText());
               ET2.setText("");
                   
           }
       });

    }