RecyclerView大家常用，但是如何给加载出来的item增加间隔很多人都不知道，下面是方法，直接上代码了：
LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(layoutManager);
qujangAdapter = new QujiangAdapter(qujiangList, getActivity());
//设置item间距，30dp
recyclerView.addItemDecoration(new SpaceItemDecoration(30));
recyclerView.setAdapter(qujangAdapter);
上面的代码是用一个LinearLayoutManager 加载RecyclerView，和一般加载代码不一样的是多了 recyclerView.addItemDecoration(new SpaceItemDecoration(30)); 这一行代码。
下面是SpaceItemDecoration类的实现：
class SpaceItemDecoration extends RecyclerView.ItemDecoration {
int mSpace;
/**
* Retrieve any offsets for the given item. Each field of <code>outRect</code> specifies
* the number of pixels that the item view should be inset by, similar to padding or margin.
* The default implementation sets the bounds of outRect to 0 and returns.
* <p>
* <p>
* If this ItemDecoration does not affect the positioning of item views, it should set
* all four fields of <code>outRect</code> (left, top, right, bottom) to zero
* before returning.
* <p>
* <p>
* If you need to access Adapter for additional data, you can call
* {@link RecyclerView#getChildAdapterPosition(View)} to get the adapter position of the
* View.
*
* @param outRect Rect to receive the output.
* @param view The child view to decorate
* @param parent RecyclerView this ItemDecoration is decorating
* @param state The current state of RecyclerView.
*/
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
outRect.left = mSpace;
outRect.right = mSpace;
outRect.bottom = mSpace;
if (parent.getChildAdapterPosition(view) == 0) {
outRect.top = mSpace;
}
}
public SpaceItemDecoration(int space) {
this.mSpace = space;
}
}
在该类的getItemOffsets方法中设置item各个方向的间距。这里面加入了如果是RecyclerView的第一个子项，则设置该子项上方的间距。
运行出来之后就会发现每个item四周都有间距了。