[移动开发]RecyclerView异常：java.lang.IndexOutOfBoundsException: Inconsistency detected

一. 出现原因：快速添加和删除列表数据，列表是可以滑动的，概率出现该问题
java.lang.IndexOutOfBoundsException：检测到不一致。视图持有者适配器positionViewHolder无效。

 java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter
  at androidx.recyclerview.widget.RecyclerView$Recycler.validateViewHolderForOffsetPosition(RecyclerView.java:5974)
        at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6158)
        at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6118)
        at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6114)
        at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2303)
        at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1627)
        at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
        at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:665)
        at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep1(RecyclerView.java:4085)
        at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3849)
        at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4404)
        at android.view.View.layout(View.java:17653)
        at android.view.ViewGroup.layout(ViewGroup.java:5575)
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
        at android.view.View.layout(View.java:17653)
        at android.view.ViewGroup.layout(ViewGroup.java:5575)
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
        at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1730)
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1496)
        at android.view.View.layout(View.java:17653)
        at android.view.ViewGroup.layout(ViewGroup.java:5575)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
        at android.view.View.layout(View.java:17653)
        at android.view.ViewGroup.layout(ViewGroup.java:5575)
        at androidx.recyclerview.widget.RecyclerView$LayoutManager.layoutDecoratedWithMargins(RecyclerView.java:9587)
        at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1685)
        at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
        at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:665)
        at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4134)
        at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3851)
        at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4404)
        at android.view.View.layout(View.java:17653)
        at android.view.ViewGroup.layout(ViewGroup.java:5575)
        at androidx.viewpager2.widget.ViewPager2.onLayout(ViewPager2.java:527)
        at android.view.View.layout(View.java:17653)
        at android.view.ViewGroup.layout(ViewGroup.java:5575)
        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:17653)
        at android.view.ViewGroup.layout(ViewGroup.java:5575)
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
    	at android.widget.LinearLayout.layoutH

二. 问题原因： stackoverflow 上解释
三. 解决方法
方法一
自己写一个类继承LinearLayoutManager的包装类，在onLayoutChildren()方法里try-catch捕获该异常。

public class WrapContentLinearLayoutManager extends LinearLayoutManager {
    public WrapContentLinearLayoutManager(Context context) {
        super(context);
    }
 
    public WrapContentLinearLayoutManager(Context context, int orientation, boolean reverseLayout) {
        super(context, orientation, reverseLayout);
    }
 
    public WrapContentLinearLayoutManager(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }
 
    @Override
    public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
        try {
            super.onLayoutChildren(recycler, state);
        } catch (IndexOutOfBoundsException e) {
            e.printStackTrace();
        }
    }
}

方法二
在进行数据移除和数据增加时，务必要保证RecyclerView的Adapter中的数据集和移除／添加等操作后的数据集保持一致！

前者是在该Adapter内部，不妨叫做内部数据集，后者是开发人员传过给Adapter的，不妨叫外部数据集。更新RecyclerView数据时，需要保证外部数据集和内部数据集实时保持一致。

外部数据集同步到内部数据集，使用如下的方法：

notifyItemRangeRemoved();
notifyItemRangeInserted();
notifyItemRangeChanged();
notifyDataSetChanged();     //更新内部数据集，没有默认的动画效果，效率页不如上面的方法，官方不推荐使用

RecyclerView的Adapter里，发生异常的错误代码如下：

public void notifyData(List<PoiItem> poiItemList) {
    if (poiItemList != null ) {
        mPoiItems.clear();
        mPoiItems.addAll(poiItemList);
        notifyItemRangeChanged(0, poiItemList.size());
    }
}

错误分析：

mPoiItems是外部数据集，对该外部数据集做了两个操作：先移除数据，然后添加数据，之后notify数据集。这里，添加数数据时（Adapter的内部数据集内容还处在外部数据集移除数据之前），造成了内部和外部数据集不一致。

这是一方面，另一方面，我使用了notifyItemRangeChanged()来更新数据，如果poiItemList传过来的新数据和原来mPoiItems的数据数量不一致，就会出现内部数据集和外部数据在同步后不一致，从而报错。

修复后，运行正常的代码如下：

public void notifyData(List<PoiItem> poiItemList) {
    if (poiItemList != null) {
        int previousSize = mPoiItems.size();
        mPoiItems.clear();
        notifyItemRangeRemoved(0, previousSize);
        mPoiItems.addAll(poiItemList);
        notifyItemRangeInserted(0, poiItemList.size());
    }
}

每一次对外部数据集做改动时，都需要紧接着主动对外部数据集和内部数据集做一次同步操作，动画效果也得到了保持，

方法三
设置RecyclerView的布局管理为WrapContentLinearLayoutManager对象

mRecyclerView.setLayoutManager(new WrapContentLinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));