点击手机 menu 硬件按钮后的显示及处理

public class ActivityMenu extends Activity {
    public static final int ITEM0 = Menu.FIRST;
    public static final int ITEM1 = Menu.FIRST + 1;

   
    Button button1;
    Button button2;
   
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main1);
        button1 = (Button) findViewById(R.id.button1);
        button2 = (Button) findViewById(R.id.button2);
        button1.setVisibility(View.INVISIBLE);
        button2.setVisibility(View.INVISIBLE);
       

    }
    @Override
    /*
     * menu.findItem(EXIT_ID);找到特定的MenuItem
     * MenuItem.setIcon.可以设置menu按钮的背景
     */
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);
        menu.add(0, ITEM0, 0, "显示button1");
        menu.add(0, ITEM1, 0, "显示button2");
        menu.findItem(ITEM1);
        return true;
    }
   
   
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
        case ITEM0:
            actionClickMenuItem1();
        break;
        case ITEM1:
            actionClickMenuItem2(); break;

        }
        return super.onOptionsItemSelected(item);}
    /*
     * 点击第一个menu的第一个按钮执行的动作
     */
    private void actionClickMenuItem1(){
        setTitle("button1 可见");
        button1.setVisibility(View.VISIBLE);
        button2.setVisibility(View.INVISIBLE);
    }
    /*
     * 点击第二个个menu的第一个按钮执行的动作
     */
    private void actionClickMenuItem2(){
        setTitle("button2 可见");
        button1.setVisibility(View.INVISIBLE);
        button2.setVisibility(View.VISIBLE);
    }
}