上下文上菜单

 private ListView listView;
    //数据源
    private List<Object>list=new ArrayList<>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        listView=findViewById(R.id.list_view);
        //数据源
        for(int i=0;i<=20;i++){
            list.add("123123123"+i);
        }
        //适配器
        ArrayAdapter<Object> objectArrayAdapter = new ArrayAdapter<>(Main2Activity.this, R.layout.support_simple_spinner_dropdown_item, list);
        listView.setAdapter(objectArrayAdapter);
        registerForContextMenu(listView);
    }
    //重写 适配数据给Menu
    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        getMenuInflater().inflate(R.menu.menu,menu);
        super.onCreateContextMenu(menu, v, menuInfo);
    }

    //重写状态的监听
    @Override
    public boolean onContextItemSelected(MenuItem item) {
        switch (item.getItemId()){
            case R.id.a:
                //定时显示 吐司
                new CountDownTimer(5000, 1000) {
                    @Override
                    public void onTick(long millisUntilFinished) {

                    }
                    @Override
                    public void onFinish() {
                        Toast.makeText( Main2Activity.this, "ok了，小老弟！", Toast.LENGTH_SHORT).show();
                    }
                }.start();
                break;
            case R.id.b:
                Toast.makeText(Main2Activity.this, "短点击", Toast.LENGTH_SHORT).show();
                break;
            case R.id.c:
                Toast.makeText(Main2Activity.this, "短点击", Toast.LENGTH_SHORT).show();
                break;
        }
        return super.onContextItemSelected(item);
    }