安卓的上下文菜单只触发了一次

在通过xml定义编写安卓的上下文菜单程序时，出现了模拟器上程序长按只能出现一次菜单的情况，再次长按无法再出现菜单。
主Activity代码如下：

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        TextView textOne = (TextView)findViewById(R.id.textOne);
        TextView textTwo = (TextView)findViewById(R.id.textTwo);
        this.registerForContextMenu(textOne);
        this.registerForContextMenu(textTwo);
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View view, ContextMenuInfo menuInfo) {
        if(view.getId() == R.id.textOne) {
            if(menu.size() == 0) {
                MenuInflater inflater = this.getMenuInflater();
                inflater.inflate(R.menu.font_size, menu);
            }
        }
        if(view.getId() == R.id.textTwo) {
            if(menu.size() == 0) {
                MenuInflater inflater = this.getMenuInflater();
                inflater.inflate(R.menu.font_color, menu);
            }
        }
    }

    void setFontSize(int size) {
        setContentView(R.layout.activity_main);
        TextView textOne2 = (TextView)findViewById(R.id.textOne);
        TextView textTwo2 = (TextView)findViewById(R.id.textTwo);
        textOne2.setTextSize(size);
        textTwo2.setTextSize(size);
    }
    void setFontColor(int c) {
        setContentView(R.layout.activity_main);
        TextView textOne2 = (TextView)findViewById(R.id.textOne);
        TextView textTwo2 = (TextView)findViewById(R.id.textTwo);
        textOne2.setTextColor(c);
        textTwo2.setTextColor(c);
    }

    @Override
    public boolean onContextItemSelected(MenuItem item) {
        switch(item.getItemId()) {
        case R.id.size_5:
            setFontSize(16); return true;
        case R.id.size_4:
            setFontSize(25); return true;
        case R.id.size_3:
            setFontSize(30); return true;
        case R.id.size_2:
            setFontSize(35); return true;
        case R.id.red:
            setFontColor(Color.RED); return true;
        case R.id.blue:
            setFontColor(Color.BLUE); return true;
        case R.id.green:
            setFontColor(Color.GREEN); return true;
        case R.id.black:
            setFontColor(Color.BLACK); return true;
        default:
            return super.onContextItemSelected(item);
        }
    }
}

请问有没有大神遇到过，知道怎么解决的？亦或我的代码实现有没有问题，欢迎指正。

https://www.cnblogs.com/naray/p/5358438.html