RecyclerView下拉刷新item间距变大的问题

RecyclerView下拉刷新item间距变大的问题

现在列表类布局是非常常见的布局，大多数都是使用RecyclerView来实现。日前在项目中就有一个页面是列表类的，稍微有些不同的是单个item中需要显示图片，类似朋友圈那样的，这样就嵌套了一个RecyclerView,效果见下图：

相关代码如下：

  @Overridepublic void onBindViewHolder(CommonViewHolder viewHolder, int i) {//图片使用的RecyclerView RecyclerView recyclerView = viewHolder.getView(R.id.recyclerview);recyclerView.setVisibility(View.VISIBLE);GridLayoutManager gridLayoutManager = new GridLayoutManager(recyclerView.getContext(), 3);recyclerView.setLayoutManager(gridLayoutManager);GridItemDecoration gridItemDecoration = new GridItemDecoration(3, DensityUtil.dip2px(3));recyclerView.addItemDecoration(gridItemDecoration);recyclerView.setAdapter(new PostListImagesAdapter(data.getPost_pic_url()));recyclerView.setOnTouchListener(new View.OnTouchListener() {@Overridepublic boolean onTouch(View v, MotionEvent event) {switch (event.getAction()) {case MotionEvent.ACTION_DOWN:break;case MotionEvent.ACTION_UP:ContentStartAcHelper.startPostDetailAc(v.getContext(), String.valueOf(data.getPost_id()), data.getPost_type(), false);break;}return false;}});}

这时在下拉刷新时就会发现，图片间的间距每次都会变大，分析上面的代码，大概可猜测到 是recyclerView.addItemDecoration(gridItemDecoration)的问题，在下拉刷新或者上下滑动后，调用onBindViewHolder方法，导致每次都会执行recyclerView.addItemDecoration(gridItemDecoration)，点击方法进入源码都发现，此方法会将每次add的Decoration累加起来：

   public void addItemDecoration(ItemDecoration decor) {addItemDecoration(decor, -1);}public void addItemDecoration(ItemDecoration decor, int index) {if (mLayout != null) {mLayout.assertNotInLayoutOrScroll("Cannot add item decoration during a scroll  or"+ " layout");}if (mItemDecorations.isEmpty()) {setWillNotDraw(false);}if (index < 0) {mItemDecorations.add(decor);} else {mItemDecorations.add(index, decor);}markItemDecorInsetsDirty();requestLayout();}

找到问题所在，那么就好解决了，只要在recyclerView.addItemDecoration时增加判断是否已经有ItemDecoration即可：

   if (recyclerView.getItemDecorationCount() == 0 ) {recyclerView.addItemDecoration(gridItemDecoration);}

问题结局！
另外，图片Recyclerview使用的是GridLayoutManager，在图片空白的位置点击是没有效果的，可通过设置setOnTouchListener来实现点击效果，代码见上。