检测到不一致。无效的项目位置 0（偏移量：-1）... RecyclerView 在删除第一个项目时崩溃

Question

我正在尝试删除RecyclerView 中的第一项。使用 livedata 和 diffutil 监视列表的更改。 仅当RecyclerView 中的第一项被删除（第 0 个索引）时才会发生崩溃。这似乎与其他相关问题相似。快速滚动等时不会出现此问题。仅在删除第 0 位的项目时才会出现此问题。该项目本身将从数据库中删除。但应用程序崩溃。我尝试从RecyclerView 类中追溯错误：.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5923)

来自 RecyclerView.java：

if (offsetPosition < 0 || offsetPosition >= mAdapter.getItemCount()) {
            throw new IndexOutOfBoundsException("Inconsistency detected. Invalid item "
                    + "position " + position + "(offset:" + offsetPosition + ")."
                    + "state:" + mState.getItemCount());
        }

偏移位置小于0（-1）

完整的错误堆栈：

03-23 08:55:38.739 25087-25087/com.application.essentials E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.application.essentials, PID: 25087
java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid item position 0(offset:-1).state:3 android.support.v7.widget.RecyclerView{41df14f0 VFED.V.. ......ID 0,0-480,606 #7f080084 app:id/recycler_view}, adapter:com.application.essentials.model.AlarmsAdapter@41dd7d80, layout:android.support.v7.widget.LinearLayoutManager@41e10b80, context:com.application.essentials.MainActivity@41d37840
    at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5923)
    at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5858)
    at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5854)
    at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2230)
    at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1557)
    at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1517)
    at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:622)
    at android.support.v7.widget.RecyclerView.dispatchLayoutStep1(RecyclerView.java:3875)
    at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3639)
    at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:4194)
    at android.view.View.layout(View.java:15819)
    at android.view.ViewGroup.layout(ViewGroup.java:4884)
    at android.support.design.widget.CoordinatorLayout.layoutChild(CoordinatorLayout.java:1183)
    at android.support.design.widget.CoordinatorLayout.onLayoutChild(CoordinatorLayout.java:870)
    at android.support.design.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:889)
    at android.view.View.layout(View.java:15819)
    at android.view.ViewGroup.layout(ViewGroup.java:4884)
    at android.support.v4.view.ViewPager.onLayout(ViewPager.java:1775)
    at android.view.View.layout(View.java:15819)
    at android.view.ViewGroup.layout(ViewGroup.java:4884)
    at android.support.design.widget.HeaderScrollingViewBehavior.layoutChild(HeaderScrollingViewBehavior.java:142)
    at android.support.design.widget.ViewOffsetBehavior.onLayoutChild(ViewOffsetBehavior.java:41)
    at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onLayoutChild(AppBarLayout.java:1556)
    at android.support.design.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:888)
    at android.view.View.layout(View.java:15819)
    at android.view.ViewGroup.layout(ViewGroup.java:4884)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
    at android.view.View.layout(View.java:15819)
    at android.view.ViewGroup.layout(ViewGroup.java:4884)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1677)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1531)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1440)
    at android.view.View.layout(View.java:15819)
    at android.view.ViewGroup.layout(ViewGroup.java:4884)...

Answer 1

问题出在适配器上。我在适配器构造函数中使用了 setHasStableIds(true);，以避免“更改时项目闪烁”。我已经覆盖了这两种方法： public long getItemId(int position) {...} 和 public int getItemViewType(int position) {...}

崩溃消失了，第 0 项被删除，一旦我删除了这一行：setHasStableIds(true);在构造函数中。但是项目在闪烁。 问题在于我在被覆盖的方法中返回的 什么。下面的代码有问题：

    @Override
public long getItemId(int position) {
     return position;
}

@Override
public int getItemViewType(int position) {
    return position;
}

我返回的位置不是唯一的。我将项目的 id 作为唯一 ID 返回，问题就消失了。

正确代码：

    @Override
public long getItemId(int position) {
   return mAlarmEntityList.get(position).getAlarmId();
}

@Override
public int getItemViewType(int position) {
    return position;
}

我花了几个小时找出问题所在。这些答案帮助了我：Inconsistency detected in RecyclerView, How to change contents of RecyclerView while scrolling

How to prevent RecyclerView item from blinking after notifyItemChanged(pos)?

希望这对某人有所帮助！