[b]//复写onCreateOptionsMenu()方法,弹出菜单栏 [/b]    @Override     public boolean onCreateOptionsMenu(Menu menu) {         getMenuInflater().inflate(R.menu.activity_main, menu);         return true;     } [b]//复写back按钮,如果只是复写返回按钮,复写Activity中的onBackPressed()方法就可以 [/b]        @Override     public void onBackPressed() {         // TODO Auto-generated method stub         super.onBackPressed();         Toast.makeText(MainActivity.this, "onBackPressed!!", Toast.LENGTH_SHORT).show();     } [b]//   复写搜索按钮 [/b]//    复写onKeyDown()方法,该方法可以复写很多按钮：数字键、Menu键、返回键等等     @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);     }