Android 如何使用ScnViewGestures.Forms在Xamarin.Forms中创建具有触地和触地事件的视图

Forms是一个Nuget软件包，允许使用自定义触摸处理程序在页面中设置任何子视图。然而，通过阅读github上的sparce docu，不容易理解如何使用它。那么，如何使用Xamarin.Forms中的触地和触地事件处理程序创建自定义视图呢？

下面是一个工作代码示例。别忘了安装nuget软件包ScnViewGestures.Forms，并按如下方式初始化它：

iOS（在AppDelegate.cs中）：

安卓：

Xamarin.Forms.Forms.Init (this, bundle);
ViewGesturesRenderer.Init();

WinPhone：

Xamarin.Forms.Forms.Init ();
ViewGesturesRenderer.Init();

然后您可以创建像这个小按钮一样的自定义视图，它分别处理向下和向上事件，这是Xamarin.Forms标准按钮无法做到的

using System;
using System.Collections.Generic;
using Xamarin.Forms;
using ScnViewGestures.Plugin.Forms;

namespace ViewGesturesExample {
    public partial class ButtonView : ContentView
    {
        public ButtonView ()
        {
            InitializeComponent ();
            Content = _gestures = new ViewGestures () {
                HorizontalOptions = new LayoutOptions(LayoutAlignment.Fill, true),
                VerticalOptions = new LayoutOptions(LayoutAlignment.Fill, true),
            };
            _gestures.Content=_button=new Label () {
                HorizontalOptions = new LayoutOptions(LayoutAlignment.Fill, true),
                VerticalOptions = new LayoutOptions(LayoutAlignment.Fill, true),
                XAlign = TextAlignment.Center,
                YAlign = TextAlignment.Center,
            };
            _gestures.TouchBegan += OnTouchDown;
            _gestures.TouchEnded += OnTouchUp;          
            // here you have more events like 
            //Tap;
            //SwipeLeft;
            //SwipeRight;
            //SwipeUp;
            //SwipeDown.
        }

            Label _button;
            ViewGestures _gestures;

            private void OnTouchDown(object sender, EventArgs args) {

            }

            private void OnTouchUp(object sender, EventArgs args) {

            }
        }

}

---

对于所有寻找所用Plugin源代码的人：

using System;
using System.Collections.Generic;
using Xamarin.Forms;
using ScnViewGestures.Plugin.Forms;

namespace ViewGesturesExample {
    public partial class ButtonView : ContentView
    {
        public ButtonView ()
        {
            InitializeComponent ();
            Content = _gestures = new ViewGestures () {
                HorizontalOptions = new LayoutOptions(LayoutAlignment.Fill, true),
                VerticalOptions = new LayoutOptions(LayoutAlignment.Fill, true),
            };
            _gestures.Content=_button=new Label () {
                HorizontalOptions = new LayoutOptions(LayoutAlignment.Fill, true),
                VerticalOptions = new LayoutOptions(LayoutAlignment.Fill, true),
                XAlign = TextAlignment.Center,
                YAlign = TextAlignment.Center,
            };
            _gestures.TouchBegan += OnTouchDown;
            _gestures.TouchEnded += OnTouchUp;          
            // here you have more events like 
            //Tap;
            //SwipeLeft;
            //SwipeRight;
            //SwipeUp;
            //SwipeDown.
        }

            Label _button;
            ViewGestures _gestures;

            private void OnTouchDown(object sender, EventArgs args) {

            }

            private void OnTouchUp(object sender, EventArgs args) {

            }
        }

}