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Question

我搜索了几个小时以找到解决此问题的有效解决方案，并设法创建了一个。我希望有人也可以使用这个解决方案。

Answer 1

private GestureDetector _gestureDetector;
private GestureListener _gestureListener;

protected override void OnCreate(Bundle bundle)
{
        _gestureListener = new GestureListener();
        _gestureListener.LeftEvent += GestureLeft;
        _gestureListener.RightEvent += GestureRight;
        _gestureDetector = new GestureDetector(this, _gestureListener);
}

private void GestureLeft()
{
    if (TabHost.CurrentTab - 1 < 0)
    {
        TabHost.CurrentTab = TabHost.TabWidget.TabCount - 1;
    }
    else
    {
        TabHost.CurrentTab--;
     }
}

private void GestureRight()
{
    if (TabHost.CurrentTab + 1 >= TabHost.TabWidget.TabCount)
    {
        TabHost.CurrentTab = 0;
    }
    else
    {
        TabHost.CurrentTab++;
    }
}

 public override bool DispatchTouchEvent(MotionEvent ev)
 {
    _gestureDetector.OnTouchEvent(ev);
    return base.DispatchTouchEvent(ev);
 }

GestureListener.cs（在网上找到了这个解决方案，可惜忘记出处了，还是感谢原作者）：

using System;
using Android.Views;

namespace Utils
{
public class GestureListener : Java.Lang.Object, GestureDetector.IOnGestureListener
{
    public event Action LeftEvent;
    public event Action RightEvent;
    private static int SWIPE_MAX_OFF_PATH = 250;
    private static int SWIPE_MIN_DISTANCE = 120;
    private static int SWIPE_THRESHOLD_VELOCITY = 200;

    public GestureListener()
    {
    }

    public bool OnDown(MotionEvent e)
    {
        return true;
    }

    public bool OnFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
    {
        try
        {
            if (Math.Abs(e1.GetY() - e2.GetY()) > SWIPE_MAX_OFF_PATH)
                return false;
            // right to left swipe
            if (e1.GetX() - e2.GetX() > SWIPE_MIN_DISTANCE && Math.Abs(velocityX) > SWIPE_THRESHOLD_VELOCITY && LeftEvent != null)
                LeftEvent();//Toast.MakeText(view.Context, "Left Swipe", ToastLength.Short).Show();
            else if (e2.GetX() - e1.GetX() > SWIPE_MIN_DISTANCE && Math.Abs(velocityX) > SWIPE_THRESHOLD_VELOCITY && RightEvent != null)
                RightEvent();// Toast.MakeText(view.Context, "Right Swipe", ToastLength.Short).Show();
        }
        catch (Exception e)
        {
            // nothing
        }
        return false;
    }

    public void OnLongPress(MotionEvent e)
    {
    }

    public bool OnScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)
    {
        return true;
    }

    public void OnShowPress(MotionEvent e)
    {
    }

    public bool OnSingleTapUp(MotionEvent e)
    {
        return true;
    }
}

}

Answer 2

谢谢，按预期工作。下面是一个 ActionBarSherlock 派生类：

private void GestureLeft()
    {
        Xamarin.ActionbarSherlockBinding.App.ActionBar ab = base.SupportActionBar;

        if (ab.SelectedTab.Position - 1 < 0)
        {
            //ab.SelectTab(ab.GetTabAt(ab.SelectedTab.Position - 1));
            ab.SelectTab(ab.GetTabAt(ab.TabCount - 1 ));
        }
        else
        {
            //TabHost.CurrentTab--;
            ab.SelectTab(ab.GetTabAt(ab.SelectedTab.Position - 1));
        }
    }

    private void GestureRight()
    {
        Xamarin.ActionbarSherlockBinding.App.ActionBar ab = base.SupportActionBar;


        if (ab.SelectedTab.Position+1 >= ab.TabCount) //TabHost.CurrentTab + 1 >= TabHost.TabWidget.TabCount)
        {
            ab.SelectTab(ab.GetTabAt(0));
            //TabHost.CurrentTab = 0;
        }
        else
        {
            ab.SelectTab(ab.GetTabAt(ab.SelectedTab.Position + 1));
            //TabHost.CurrentTab++;
        }
    }