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  • Android RecyclerView 设置item间隔的方法

    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。

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  • 原文地址:https://www.cnblogs.com/zhujiabin/p/7436569.html
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