Recyclerview 中已经设置了 OnFlingListener 的一个实例

Question

我在我的 Android 应用中使用了 RecyclerView。我的 RecyclerView 中有很多卡片视图，因此一次只向用户显示 1 个卡片视图。用户必须滑动才能看到下一张卡片。

我遇到了一个问题，即当用户滑动时，recyclerview 会滚动到最后。相反，我需要的是当用户滑动时，向用户显示下一张卡片，如本文所述。

How to make swipe on horizontal recyclerview bring only the next item into view - Android

SnapHelper snapHelper = new PagerSnapHelper();
snapHelper.attachToRecyclerView(recyclerView);

我尝试了上面链接中提到的答案。但是当用户滑动时我遇到了一个异常。

请帮我解决。

错误

java.lang.IllegalStateException: An instance of OnFlingListener already set.
    at android.support.v7.widget.SnapHelper.setupCallbacks(SnapHelper.java:114)
    at android.support.v7.widget.SnapHelper.attachToRecyclerView(SnapHelper.java:102)
    at com.abc.ui.trm.TrCard.setupCardView(TrCard.java:62)
    at com.abc.ui.trm.TrCard.setupCardView(TrCard.java:29)
    at com.abc.ui.core.card.BaseCardView.processCardView(BaseCardView.java:134)
    at com.abc.ui.card.CardRecyclerAdapter.onViewAttachedToWindow(CardRecyclerAdapter.java:398)
    at android.support.v7.widget.RecyclerView.dispatchChildAttached(RecyclerView.java:6758)
    at android.support.v7.widget.RecyclerView$5.addView(RecyclerView.java:696)
    at android.support.v7.widget.ChildHelper.addView(ChildHelper.java:107)
    at android.support.v7.widget.RecyclerView$LayoutManager.addViewInt(RecyclerView.java:7697)
    at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:7655)
    at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:7643)
    at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1539)
    at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1488)
    at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:585)
    at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3506)
    at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3254)
    at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3767)
    at android.view.View.layout(View.java:18799)
    at android.view.ViewGroup.layout(ViewGroup.java:5952)
    at com.abc.ui.core.refresh.LegacySwipeRefreshLayout.onLayout(LegacySwipeRefreshLayout.java:337)
    at android.view.View.layout(View.java:18799)
    at android.view.ViewGroup.layout(ViewGroup.java:5952)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
    at android.view.View.layout(View.java:18799)
    at android.view.ViewGroup.layout(ViewGroup.java:5952)
    at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1079)
    at android.view.View.layout(View.java:18799)
    at android.view.ViewGroup.layout(ViewGroup.java:5952)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
    at android.view.View.layout(View.java:18799)
    at android.view.ViewGroup.layout(ViewGroup.java:5952)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
    at android.view.View.layout(View.java:18799)
    at android.view.ViewGroup.layout(ViewGroup.java:5952)
    at android.support.v4.widget.DrawerLayout.onLayout(DrawerLayout.java:1193)
    at android.view.View.layout(View.java:18799)
    at android.view.ViewGroup.layout(ViewGroup.java:5952)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
    at android.view.View.layout(View.java:18799)
    at android.view.ViewGroup.layout(ViewGroup.java:5952)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
    at android.view.View.layout(View.java:18799)
    at android.view.ViewGroup.layout(ViewGroup.java:5952)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
    at com.android.internal.policy.DecorView.onLayout(DecorView.java:822)
    at android.view.View.layout(View.java:18799)
    at android.view.ViewGroup.layout(ViewGroup.java:5952)

Answer 1

我设法通过添加这一行来解决这个问题

recyclerView.setOnFlingListener(null); 

之前

snapHelper.attachToRecyclerView(recyclerView);

Answer 2

您可以在添加之前先在 RecyclerView 上检查 OnFlingListener

if (recycler.getOnFlingListener() == null)
        snapHelper.attachToRecyclerView(recycler);

Answer 3

您所要做的就是放置

SnapHelper snapHelper = new PagerSnapHelper();
snapHelper.attachToRecyclerView(recyclerView);

在 onCreateViewHolder 内而不是 onBindViewHolder

Answer 4

发生这种情况是因为您以某种方式设置了两次SnapPagerHelper。请注意，如果您在另一个 RecyclerView 中有一个 RecyclerView，这应该只发生在彼此的构造函数或 Kotlin 的 init {} 块中（每个项目一次）。
我的情况和你的很相似，因为我有一个大的垂直RecyclerView 和一个小的RecyclerView。

会导致异常的代码：

 fun bind(value: ArrayList<Item>) {
    listAdapter = ItemCellDelegate(value)

    val manager = LinearLayoutManager(itemView.context)
    manager.orientation = LinearLayoutManager.HORIZONTAL

    horizontalRecyclerView?.apply {
        layoutManager = manager
        adapter = listAdapter
        setHasFixedSize(true)
    }

    val snapHelper: SnapHelper = PagerSnapHelper()
    snapHelper.attachToRecyclerView(horizontalRecyclerView)

}

使用init {} 块的正确代码：

init {
    val snapHelper: SnapHelper = PagerSnapHelper()
    snapHelper.attachToRecyclerView(horizontalRecyclerView)
}

Answer 5

类似这样的：

override fun onAttachedToWindow(view: RecyclerView) {
    super.onAttachedToWindow(view)
    view.onFlingListener = null;
    StartSnapHelper().attachToRecyclerView(view)
}