当RecyclerView遇到Inconsistency detected崩溃时

近来项目里，RecyclerView更新数据偶尔出现crash，错误日志如下：

java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder{2064e5c6 position=2 id=-1, oldPos=2, pLpos:-1 scrap [attachedScrap] tmpDetached no parent}
at android.support.v7.widget.RecyclerView$Recycler.validateViewHolderForOffsetPosition(RecyclerView.java:4505)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4636)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4617)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:1994)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1390)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1353)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:574)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep1(RecyclerView.java:2979)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:2904)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3283)
at android.view.View.layout(View.java:15912)
at android.view.ViewGroup.layout(ViewGroup.java:5108)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1959)
at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1948)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1724)
at android.view.View.layout(View.java:15912)
at android.view.ViewGroup.layout(ViewGroup.java:5108)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1959)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1813)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1722)
at android.view.View.layout(View.java:15912)
at android.view.ViewGroup.layout(ViewGroup.java:5108)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:633)
at android.widget.FrameLayout.onLayout(FrameLayout.java:568)
at android.view.View.layout(View.java:15912)
at android.view.ViewGroup.layout(ViewGroup.java:5108)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1959)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1813)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1722)
at android.view.View.layout(View.java:15912)
at android.view.ViewGroup.layout(ViewGroup.java:5108)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:633)
at android.widget.FrameLayout.onLayout(FrameLayout.java:568)
at android.view.View.layout(View.java:15912)
at android.view.ViewGroup.layout(ViewGroup.java:5108)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:633)
at android.widget.FrameLayout.onLayout(FrameLayout.java:568)
at android.view.View.layout(View.java:15912)
at android.view.ViewGroup.layout(ViewGroup.java:5108)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1959)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1813)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1722)
at android.view.View.layout(View.java:15912)
at android.view.ViewGroup.layout(ViewGroup.java:5108)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:633)
at android.widget.FrameLayout.onLayout(FrameLayout.java:568)
at android.view.View.layout(View.java:15912)
at android.view.ViewGroup.layout(ViewGroup.java:5108)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:633)
at android.widget.FrameLayout.onLayout(FrameLayout.java:568)
at android.view.View.layout(View.java:15912)
at android.view.ViewGroup.layout(ViewGroup.java:5108)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:633)
at android.widget.FrameLayout.onLayout(FrameLayout.java:568)
at android.view.View.layout(View.java:15912)
at android.view.ViewGroup.layout(ViewGroup.java:5108)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1959)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1813)
at android.widget.Line  

遇到这类错误java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder，通过查阅Stackoverflow和资料，总结了如下情况和解决方法：

方法一

自己写一个继承LinearLayoutManager的包装类，在onLayoutChildren()方法里try-catch捕获该异常。

@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！

这里，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();

这里对notifyDataSetChange()做些说明：
使用该方法的更新内部数据集，没有默认的动画效果，同时更新数据的效率页不如上面的方法，官方不推荐使用这种方式更新数据集。

Don’t call notifyDataSetChanged if you don’t have to.

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());
    }
}

修复分析：

每次对外部数据集做改动时，主动和内部数据集做一次同步操作，动画效果也得到了保持（使用方法三，动画效果缺失）

方法三：

使用notifyDataSetChanged同步外部数据集和内部数据集。该方法简单，但是失去了动画效果，并且更新数据的性能低

use notifyDataSetChanged() will avoid this crash, but it will kill Animation and Performance.

参考文章:

1.stackoverflow 1

2.RecyclerView Bug：IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter的解决方案

3.使用RecyclerView遇到的一些问题 Inconsistency detected