java软件按钮 java中怎么设置按钮的大小

public void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);                    setContentView(R.layout.dialog_update);          setTitle("dfsdfsd");          my_btn = (ImageButton) findViewById(R.id.rig);                              //Button cancelButton = dlg.getButton(DialogInterface.BUTTON_NEGATIVE);          android.view.ViewGroup.LayoutParams cancelBtnPara = my_btn.getLayoutParams();          cancelBtnPara.height = 31480;          my_btn.setLayoutParams(cancelBtnPara);          my_btn.setOnClickListener(but_test0_listener);          this.info = (TextView)super.findViewById(R.id.shutdown1);          //this.info.setOnTouchListener(new OnTouchListenerImpl());                    my_view = super.findViewById(R.id.shutdown);          my_view.setOnTouchListener(new OnTouchListenerImpl());

}