在Xamarin Droid中运行fragment后，在Portbale中更新Xamarin表单的UI

public interface IUpdateUI
{
    void UpdateUI(string data);
}

public class MyFragment : Fragment
{
    private IUpdateUI updateUI;

    public override void OnAttach(Context context)
    {
        base.OnAttach(context);

        // 将Activity强制转换为实现了IUpdateUI接口的对象
        updateUI = (IUpdateUI)context;
    }

    public override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        // 更新UI
        updateUI.UpdateUI("更新的数据");
    }
}

public class MyPage : ContentPage, IUpdateUI
{
    private Label myLabel;

    public MyPage()
    {
        myLabel = new Label();
        Content = myLabel;
    }

    public void UpdateUI(string data)
    {
        myLabel.Text = data;
    }
}