Android 上下文菜单 PopupMenu

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        button = (Button) this.findViewById(R.id.button);

        button.setOnClickListener(new View.OnClickListener() {

            @Override
            public  onClick(View v) {
                // TODO Auto-generated method stub

                PopupMenu poMenu = new PopupMenu(MainActivity.,v);
                poMenu.setOnMenuItemClickListener( OnMenuItemClickListener() {

                    @Override
                    boolean onMenuItemClick(MenuItem item) {
                         TODO Auto-generated method stub

                        switch (item.getItemId()) {
                        case R.id.action_add:
                            Toast.makeText(MainActivity.this,"添加被点击",1).show();

                            break;
                         R.id.action_delete:
                            Toast.makeText(MainActivity.).show();
                            ;

                        default:
                            ;
                        }

                        return false;
                    }
                });

                MenuInflater inflater = poMenu.getMenuInflater();
                inflater.inflate(R.menu.main,poMenu.getMenu());
                poMenu.show();
            }
        });
    }