Xamarin手势闪烁闪烁

Question

我想要创建一个可以在屏幕上拖动的框，所以我创建了一个扩展Frame的类（但是它也可以是AbsoluteLayout，而不是BoxView，因为我需要写点东西在那个盒子里）。

CLASS DragBox

using System;
using System.Diagnostics;
using Xamarin.Forms;

namespace PanGesture
{
    public class DragBox : Frame
    {
        public DragBox()
        {
            var panGesture = new PanGestureRecognizer();
            this.GestureRecognizers.Add(panGesture);
            panGesture.PanUpdated += OnPanUpdated;
            BorderColor = Color.Blue;
            Padding = 4;
            BackgroundColor = Color.Green;
            Content = new Label
            {
                Text = "Word",
            };
        }

        private void OnPanUpdated(object sender, PanUpdatedEventArgs e)
        {
            switch (e.StatusType)
            {
                case GestureStatus.Started:
                    Debug.WriteLine("DEBUG: start dragging");
                    break;
                case GestureStatus.Running:
                    this.TranslationX = e.TotalX;
                    this.TranslationY = e.TotalY;
                    break;
                case GestureStatus.Completed:
                    Debug.WriteLine("DEBUG: drag ended");
                    break;
            }
        }
    }
}

并且在主页中，我只创建了一个DragBox实例

public partial class HomePage : ContentPage
{
    public HomePage ()
    {
       InitializeComponent ();
       DragBox box = new DragBox();
       AbsoluteLayout.SetLayoutBounds(box, new Rectangle(0.1, 0.1, 0.2, 0.2));
       AbsoluteLayout.SetLayoutFlags(box, AbsoluteLayoutFlags.All);
       container.Children.Add(box);
    }
}

问题是，当我开始拖动该框时，它具有闪烁的效果，如下图所示。怎么解决呢？还是有其他方法可以创建可拖动元素？

Answer 1

我在OnPanUpdated事件中修改了您的代码，可以在您身边尝试。

 private void OnPanUpdated(object sender, PanUpdatedEventArgs e)
    {
        switch (e.StatusType)
        {
            case GestureStatus.Started:

                Debug.WriteLine("DEBUG: start dragging");
                break;
            case GestureStatus.Running:


                this.TranslationX = _xOffset + e.TotalX;
                this.TranslationY = _yOffset + e.TotalY;

                break;
            case GestureStatus.Completed:

                _xOffset = this.TranslationX;

                _yOffset = this.TranslationY;


                Debug.WriteLine("DEBUG: drag ended");
                break;
        }
    }

如果我的回复对您有帮助，请记住将我的回复标记为答案，谢谢。