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 is out of date and should be updated.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

这是方法的说明，下标不要搞错。

其实你传入一个参数的时候，它是更新了当前位置往前的所有内容

如果你下标错了，你可以单独+1，或者-1验证一下即可。

如果内容不多，你可以直接使用notifydatasetChange()