如何禁用左侧滑动并在xamarin android中启用右侧滑动

Question

我有一个有3个片段的viewpager。在第二个片段中，我有一个按钮。目前，对于所有3个片段，正在向左和向右滑动。现在在第二个片段中，只有在点击按钮后，用户才能进入第3个屏幕。否则从第二屏幕到第三屏幕滑动应该被阻止。当用户进入第三屏幕时，他可以返回到先前的屏幕。我编写了customviewpager代码，但它不能阻止特定的滑动。请帮我解决这个问题。

CustomViewPager.cs

namespace swiping
{
    public class CustomViewPager : ViewPager
    {
        private float initialXValue;
        private SwipeDirection direction;
        private int position = 0;
        CustomViewPager myadapter;

        bool isrightswipe, isleftswipe;

        public bool ShouldAllowSwipe()
        {

            if (this.CurrentItem == 1 && isleftswipe == true)
            {

                return false;
            }

            return true;

        }



        public CustomViewPager(Context context, IAttributeSet attrs) : base(context, attrs)
        {

            //this.direction = SwipeDirection.all;

        }

        public override bool OnTouchEvent(MotionEvent e)
        {
            //base.OnTouchEvent(e);

            //if (this.IsSwipeAllowed(e))
            //{
            //  return base.OnTouchEvent(e);
            //}

            IsSwipeAllowed(e);
            if (ShouldAllowSwipe())
            {
                base.OnTouchEvent(e);
                return true;
            }





            return false;
        }





        public override bool OnInterceptTouchEvent(MotionEvent e)
        {

            if (this.IsSwipeAllowed(e))
            {
                return base.OnInterceptTouchEvent(e);
            }

            return false;
        }

        private bool IsSwipeAllowed(MotionEvent e)
        {
            //if (this.direction == SwipeDirection.all) return true;

            //if (direction == SwipeDirection.none)//disable any swipe
            //return false;

            isrightswipe = false;
            isleftswipe = false;

            if (e.Action == MotionEventActions.Down)
            {
                initialXValue = e.GetX();

            }

            if (e.Action == MotionEventActions.Move)
            {
                try
                {
                    float diffX = e.GetX() - initialXValue;
                    if (diffX > 0 && direction == SwipeDirection.right)
                    {
                        // swipe from left to right detected
                        //prev
                        isleftswipe = false;
                        isrightswipe = true;
                        return false;
                    }
                    else if (diffX < 0 && direction == SwipeDirection.left)
                    {
                        // swipe from right to left detected
                        //next
                        isleftswipe = true;
                        isrightswipe = false;
                        return false;
                    }
                }
                catch (Exception ex)
                {

                }
            }

            return true;
        }

        public void setAllowedSwipeDirection(SwipeDirection direction)
        {
            this.direction = direction;
        }

    }


    public enum SwipeDirection
    {
        all, left, right, none
    }
} 

Answer 1

我重构了你的代码并完成了解决方案。

using System;
using Android.Content;
using Android.Runtime;
using Android.Support.V4.View;
using Android.Util;
using Android.Views;

namespace Android.Base
{
    [Register("ViewPagerWithCustomSwipe")]
    public class ViewPagerWithCustomSwipe : ViewPager
    {
        private float InitialX;
        private SwipeDirection DisabledSwipeDirection;

        public ViewPagerWithCustomSwipe(Context context, IAttributeSet attrs) : base(context, attrs)
        {
        }

        protected ViewPagerWithCustomSwipe(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer)
        {
        }

        public ViewPagerWithCustomSwipe(Context context) : base(context)
        {
        }

        public override bool OnTouchEvent(MotionEvent e)
        {
            if (IsSwipeAllowed(e))
                return base.OnTouchEvent(e);

            return false;
        }

        public override bool OnInterceptTouchEvent(MotionEvent e)
        {
            if (IsSwipeAllowed(e))
                return base.OnInterceptTouchEvent(e);

            return false;
        }

        private bool IsSwipeAllowed(MotionEvent e)
        {
            if (DisabledSwipeDirection == SwipeDirection.All)
                return false;

            if (DisabledSwipeDirection == SwipeDirection.None)
                return true;

            if (e.Action == MotionEventActions.Down)
                InitialX = e.GetX();

            if (e.Action == MotionEventActions.Move)
            {
                float diffX = e.GetX() - InitialX;
                if (diffX > 0 && DisabledSwipeDirection == SwipeDirection.Right)
                    return false;

                else if (diffX < 0 && DisabledSwipeDirection == SwipeDirection.Left)
                    return false;
            }

            return true;
        }

        public void DisableSwipe(SwipeDirection direction)
        {
            DisabledSwipeDirection = direction;
        }
    }

    public enum SwipeDirection
    {
        All = 0,
        Left = 1,
        Right = 2,
        None = 3
    }
}

您需要使用控件并向其添加OnPageChangeListener。在自定义页面侦听器中，您可以通过禁用滑动来实现自己的逻辑。

如何使用它，你可以在我的github上看到：https://gist.github.com/IlyaLavrov97/4bf2fb11ea195a0bbbaa2276a1a6c586

快乐的编码！ :)