RecyclerView 数据更新方法 notifyItemChanged/notifyItemInsert/notifyIteRemoved

notifyItemInserted

java.lang.IndexOutOfBoundsException: 
Inconsistency detected. Invalid view holder adapter positionViewHolder{424b7690 position=7 id=-1, oldPos=8,pLpos:8 scrap tmpDetached no parent} at 
android.support.v7.widget.RecyclerView$Recycler.validat
eViewHolderForOffsetPosition(RecyclerView.java:4349)

工作中遇到如下问题 notifyItemInserted(list.size()-1)，一个一个的插入也没什么问题，但是快速连续插入的话就会报出IndexOutOfBoundExcetion的异常，然后崩溃。经过多方查找，翻阅Android 的相关文档，发现如下解决方法。

使用notifyItemInserted方法向末尾处添加item的时候，要使用如下的方式

notifyItemInserted(list.size());

其中list.size()才能正确的计算出插入的位置，然后在调用

notifyItemChanged(list.size());

notifyItemRemoved

使用 notifyItemRemoved方法删除时，需要使用getLayoutPosition计算位置
否则也会报出IndexOutOfBoundExcetion异常，同时使用notifyItemChanged(removePos);方法刷新一下

notifyItemChanged

事实上RecyclerView的notifyItemChanged的底层调用的是notifyItemRangeChanged：

 /**
         * Notify any registered observers that the item at position has changed.
         * Equivalent to calling notifyItemChanged(position, null);.
         *
         * 
This is an item change event, not a structural change event. It indicates that any
         * reflection of the data at position is out of date and should be updated.
         * The item at position retains the same identity.
         *
         * @param position Position of the item that has changed
         *
         * @see #notifyItemRangeChanged(int, int)
         */
        public final void notifyItemChanged(int position) {
            mObservable.notifyItemRangeChanged(position, 1);
        }

该方法使得RecyclerView批量范围内（range）数据更新，notifyItemChanged巧妙的将第二个参数计数器设置为1得以实现。