public class MainActivity extends Activity {

    private PopupWindow pop; 

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.test);

        //将layout的xml布局文件实例化为View类对象

        LayoutInflater inflater =LayoutInflater.from(this);

        View view =inflater.inflate(R.layout.mypop, null);

        //创建PopupWindow，参数为显示对象，宽，高

        final PopupWindow pop =new PopupWindow(view, LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);

        //PopupWindow的设置

        pop.setBackgroundDrawable(new BitmapDrawable());

        //点击外边消失

        pop.setOutsideTouchable(true);

        //设置此参数获得焦点，否则无法点击

        pop.setFocusable(true);

        //设置文本监听事件

        TextView text =(TextView) findViewById(R.id.topmenu);

        text.setOnClickListener(new OnClickListener(){

            @Override

            //判断是否已经显示，点击时如显示则隐藏，隐藏则显示

            public void onClick(View v) {

                if(pop.isShowing()){

                    pop.dismiss();

                }else{

                    pop.showAsDropDown(v);

                }

            }

        });