在视图寻呼机 2 中禁用垂直滚动

Posted 2023-04-18

【中文标题】在视图寻呼机 2 中禁用垂直滚动

【英文标题】：Disable vertical scrolling in view pager 2

【发布时间】：2020-11-14 07:55:12

【问题描述】：

我正在使用viewPager2 和标签布局。我只有 2 个片段。 我的第二个片段中有一个 RecyclerView 和一个滑动刷新布局。

我的问题是当我尝试向下滑动刷新时，它与 Viewpager 的垂直滑动冲突，我无法正确向下滑动。 那么有没有办法只禁用视图 Pager 的垂直滑动？我仍然希望它能够水平滑动。

【问题讨论】：

你找到解决办法了吗？

不，我回去查看寻呼机 1。但似乎有一个答案。 ***.com/questions/57336292/…

谢谢，我会试试的

Tanzim, @Radwa 请看看我的回答，希望对您有所帮助，

【参考方案1】：

您可以通过将 isUserInputEnabled 设置为 false 来禁用 viewpager2 滚动

viewPager2.isUserInputEnabled = false

这将禁用所有事件，但在您的情况下，我认为您只需要禁用下移操作，您需要拦截触摸侦听器并在视图寻呼机上调用 requestDisallowInterceptTouchEvent(true)。

你可以从google samples使用这个包装器

/**
 * Layout to wrap a scrollable component inside a ViewPager2. Provided as a solution to the problem
 * where pages of ViewPager2 have nested scrollable elements that scroll in the same direction as
 * ViewPager2. The scrollable element needs to be the immediate and only child of this host layout.
 *
 * This solution has limitations when using multiple levels of nested scrollable elements
 * (e.g. a horizontal RecyclerView in a vertical RecyclerView in a horizontal ViewPager2).
 */
class NestedScrollableHost : FrameLayout 
    constructor(context: Context) : super(context)
    constructor(context: Context, attrs: AttributeSet?) : super(context, attrs)

    private var touchSlop = 0
    private var initialX = 0f
    private var initialY = 0f
    private val parentViewPager: ViewPager2?
        get() 
            var v: View? = parent as? View
            while (v != null && v !is ViewPager2) 
                v = v.parent as? View
            
            return v as? ViewPager2
        

    private val child: View? get() = if (childCount > 0) getChildAt(0) else null

    init 
        touchSlop = ViewConfiguration.get(context).scaledTouchSlop
    

    private fun canChildScroll(orientation: Int, delta: Float): Boolean 
        val direction = -delta.sign.toInt()
        return when (orientation) 
            0 -> child?.canScrollHorizontally(direction) ?: false
            1 -> child?.canScrollVertically(direction) ?: false
            else -> throw IllegalArgumentException()
        
    

    override fun onInterceptTouchEvent(e: MotionEvent): Boolean 
        handleInterceptTouchEvent(e)
        return super.onInterceptTouchEvent(e)
    

    private fun handleInterceptTouchEvent(e: MotionEvent) 
        val orientation = parentViewPager?.orientation ?: return

        // Early return if child can't scroll in same direction as parent
        if (!canChildScroll(orientation, -1f) && !canChildScroll(orientation, 1f)) 
            return
        

        if (e.action == MotionEvent.ACTION_DOWN) 
            initialX = e.x
            initialY = e.y
            parent.requestDisallowInterceptTouchEvent(true)
         else if (e.action == MotionEvent.ACTION_MOVE) 
            val dx = e.x - initialX
            val dy = e.y - initialY
            val isVpHorizontal = orientation == ORIENTATION_HORIZONTAL

            // assuming ViewPager2 touch-slop is 2x touch-slop of child
            val scaledDx = dx.absoluteValue * if (isVpHorizontal) .5f else 1f
            val scaledDy = dy.absoluteValue * if (isVpHorizontal) 1f else .5f

            if (scaledDx > touchSlop || scaledDy > touchSlop) 
                if (isVpHorizontal == (scaledDy > scaledDx)) 
                    // Gesture is perpendicular, allow all parents to intercept
                    parent.requestDisallowInterceptTouchEvent(false)
                 else 
                    // Gesture is parallel, query child if movement in that direction is possible
                    if (canChildScroll(orientation, if (isVpHorizontal) dx else dy)) 
                        // Child can scroll, disallow all parents to intercept
                        parent.requestDisallowInterceptTouchEvent(true)
                     else 
                        // Child cannot scroll, allow all parents to intercept
                        parent.requestDisallowInterceptTouchEvent(false)
                    
                
            
        
    

然后包装你的视图分页器内容 -recyclerView- ，

    <androidx.viewpager2.integration.testapp.NestedScrollableHost
        android:layout_
        android:layout_
        android:layout_marginTop="8dp">
        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/first_rv"
            android:layout_
            android:layout_
            android:background="#FFFFFF" />
    </androidx.viewpager2.integration.testapp.NestedScrollableHost>