Android开发：TabActivity中onKeyDown无法响应的解决方法

Android中某个类继承Activity的子类TabActivity时，重载Activity中的public boolean onKeyDown(int keyCode, KeyEvent event)方法时，点击按键时并得不到响应，解决的方法是：

重载public boolean dispatchKeyEvent(KeyEvent event)方法，其示例代码如下：

   

@Override
    public boolean dispatchKeyEvent(KeyEvent event) {
        if (event.getKeyCode() == KeyEvent.KEYCODE_BACK) {
            if (event.getAction() == KeyEvent.ACTION_DOWN && event.getRepeatCount() == 0) {
                this.showTips();//这是自定义的代码
            }
            return true;
        }
        return super.dispatchKeyEvent(event);
    }

private void showTips() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setMessage("退出后，要重新登录，确定退出吗？");
        builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {

            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
                return;
            }
        });
        builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {

            public void onClick(DialogInterface dialog, int which) {
                finish();
            }
        });

        builder.create().show();
    }