RecyclerView 設置item間隔的方法

RecyclerView大家常用，但是如何給加載出來的item增加間隔很多人都不知道，下面是方法，直接上代碼了：

        LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
        recyclerView.setLayoutManager(layoutManager);
        qujangAdapter = new QujiangAdapter(qujiangList, getActivity());
        //設置item間距，30dp
        recyclerView.addItemDecoration(new SpaceItemDecoration(30));
        recyclerView.setAdapter(qujangAdapter);

上面的代碼是用一個LinearLayoutManager 加載RecyclerView，和一般加載代碼不一樣的是多了  recyclerView.addItemDecoration(new SpaceItemDecoration(30)); 這一行代碼。

 下面是SpaceItemDecoration類的實現：

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;
    }
}

　　在該類的getItemOffsets方法中設置item各個方向的間距。這里面加入了如果是RecyclerView的第一個子項，則設置該子項上方的間距。

     運行出來之后就會發現每個item四周都有間距了。