检测到不一致。无效的项目位置 0(offset:-1)... RecyclerView 崩溃，删除第一项

Question

我正在尝试删除我的RecyclerView. 使用 livedata 和 diffutil 监视对列表的更改。只有在RecyclerView删除第一个项目（第 0 个索引）时才会发生崩溃。这可能看起来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 个位置的项目时才会出现。项目本身从数据库中删除。但应用程序崩溃。我尝试从RecyclerView课程中追溯错误：.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5923)

从 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。我正在使用setHasStableIds(true); 在适配器构造函数中，避免“更改时项目闪烁”。我已经覆盖了两种方法：public long getItemId(int position) {...} 和 public int getItemViewType(int position) {...}

一旦我删除了以下行，崩溃就消失了并删除了第 0 个项目： setHasStableIds(true); 在构造函数中。但这些项目都在闪烁。问题是用什么我是在覆盖的方法返回。下面的代码有问题：

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

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

我返回的职位并不是唯一的。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;
}

我花了几个小时弄清楚出了什么问题。这些答案对我有帮助：在 RecyclerView 中检测到不一致，如何在滚动时更改 RecyclerView 的内容

如何防止 RecyclerView 项目在 notifyItemChanged(pos) 后闪烁？

希望这可以帮助某人！