android - 如何仅为特定的 ViewType 设置 ItemDecoration？

Question

我想为 Header Type 绘制一个默认的 ItemDecoration 到 RecycleView 中。但是 divider 是为每个 ViewType 显示的。

自定义装饰:

class DividerDecoration(context: Context, orientation: Int)
    : DividerItemDecoration(context, orientation){

    override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
        val position = parent.getChildAdapterPosition(view)
        val viewType = parent.adapter!!.getItemViewType(position)
        if (viewType == ITEM_VIEW_TYPE_HEADER){
            super.getItemOffsets(outRect, view, parent, state)
        } else {
            outRect.setEmpty()
        }
    }
}

设置:

val itemDecoration = DividerDecoration(binding.recyclerView.context, 
                                       DividerItemDecoration.VERTICAL)
binding.recyclerView.addItemDecoration(itemDecoration)

对于为什么会发生这种情况有什么建议吗？

更新

上面的代码是有效的。但是有一个错误。启动应用程序后，分隔符出现在所有元素中，然后仅出现在正确的元素中。为什么会这样？

Answer 1

下面介绍了如何根据 View 类型或位置显示或隐藏分隔线。将其包含在您的 Activity/fragment 中。

recyclerView.addItemDecoration(new DividerItemDecoration(this, linearLayoutManager.getOrientation()) {
            @Override
            public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
                Drawable d = getDrawable();
                for (int i = 0; i < parent.getChildCount(); i++) {
                    View view = parent.getChildAt(i);
                    int position = parent.getChildAdapterPosition(view);
                    int viewType = parent.getAdapter().getItemViewType(position);
                    
                    // Draw divider only for view type 2 (can also put position here to remove for certain positions)
                    if(viewType == 2) {
                        RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) view.getLayoutParams();
                        int top = view.getBottom() + params.bottomMargin;
                        int bottom = top + d.getIntrinsicHeight();
                        d.setBounds(0, top, parent.getRight(), bottom);
                        d.draw(c);
                    }
                }
            }
        });