如何让谷歌眼镜手势与Xamarin一起工作

Question

我正在使用Xamarin构建Google Glass应用程序，但无法让GestureDetector触发任何OnGesture事件。 这是我到目前为止尝试过的：

在我的活动中：

    using Gesture = Android.Glass.Touchpad.Gesture;
    using GestureDetector = Android.Glass.Touchpad.GestureDetector;
    private GestureDetector _gestureDetector;
    protected override void OnCreate(Bundle bundle)
    {
      base.OnCreate(bundle);
      this._gestureDetector = new GestureDetector(this);
      this._gestureDetector.SetBaseListener(new GestureListener());
    }
    public override bool OnGenericMotionEvent(MotionEvent e)
    {
        if (this._gestureDetector != null)
        {
            return this._gestureDetector.OnMotionEvent(e);
        }
        return false;
    }

IBaseListener 实现：

class GestureListener : GestureDetector.IBaseListener
{
    public bool OnGesture(Gesture gesture)
    {
        if (gesture == Gesture.SwipeRight)
        {
            // do something on right (forward) swipe
            return true;
        }
        else if (gesture == Gesture.SwipeLeft)
        {
            // do something on left (backwards) swipe
            return true;
        }
        return false;
    }
    public void Dispose()
    {
    }
    public IntPtr Handle { get; set; }
}

我尝试在 OnGesture 方法中设置断点，但它从未触发。 我的 IBaseListener 实现中是否缺少某些内容？

Answer 1

事实证明，我需要让我的侦听器实现扩展Java.Lang.Object，如 Xamarin 文章中关于 Android 可调用包装器。 下面是一个完全工作的示例活动。

using System;
using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
using Gesture = Android.Glass.Touchpad.Gesture;
using GestureDetector = Android.Glass.Touchpad.GestureDetector;

namespace GlassGestureTest
{
    using Android.Util;
    using Java.Util.Logging;
    [Activity(Label = "GlassGestureTest", MainLauncher = true, Icon = "@drawable/icon")]
    public class Activity1 : Activity
    {
        private GestureDetector _gestureDetector;
        int count = 1;
        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);
            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.Main);
            // Get our button from the layout resource,
            // and attach an event to it
            Button button = FindViewById<Button>(Resource.Id.MyButton);
            button.Click += delegate { button.Text = string.Format("{0} clicks!", count++); };
            this._gestureDetector = new GestureDetector(this);
            this._gestureDetector.SetBaseListener(new GestureListener());
        }
        public override bool OnGenericMotionEvent(MotionEvent e)
        {
            if (this._gestureDetector != null)
            {
                return this._gestureDetector.OnMotionEvent(e);  
            }
            return false;
        }
    }
    // Note - the key part here is to extend Java.Lang.Object in order to properly setup
    // the IntPtr field and Dispose method required by IBaseListener
    public class GestureListener : Java.Lang.Object, GestureDetector.IBaseListener
    {
        public bool OnGesture(Gesture gesture)
        {
            if (gesture == Gesture.SwipeRight)
            {
                // do something on right (forward) swipe
                return true;
            }
            else if (gesture == Gesture.SwipeLeft)
            {
                // do something on left (backwards) swipe
                return true;
            }
            else if (gesture == Gesture.SwipeDown)
            {
                // do something on the down swipe
                return true;
            }
            else if (gesture == Gesture.SwipeUp)
            {
                // do something on the up swipe
                return true;
            }
            return false;
        }
    }
}