//復寫onCreateOptionsMenu()方法,彈出菜單欄
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

//復寫back按鈕,如果只是復寫返回按鈕,復寫Activity中的onBackPressed()方法就可以
   
    @Override
    public void onBackPressed() {
        // TODO Auto-generated method stub
        super.onBackPressed();

        Toast.makeText(MainActivity.this, "onBackPressed!!", Toast.LENGTH_SHORT).show();
    }

//   復寫搜索按鈕
//    復寫onKeyDown()方法,該方法可以復寫很多按鈕：數字鍵、Menu鍵、返回鍵等等
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        // TODO Auto-generated method stub
        if(keyCode==KeyEvent.KEYCODE_MENU){

            Toast.makeText(MainActivity.this, "Search Menu", Toast.LENGTH_SHORT).show();

        }

        return super.onKeyDown(keyCode, event);
    }