RecyclerView，不同的分隔符取决于行的类型

Question

所以我有一个包含不同类型行的ListView。我想为第一行禁用分隔符，并为第二行设置另一种分隔符样式。

最佳做法是什么？

我目前通过以下方式添加分隔符：

    DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(recyclerView.getContext(),DividerItemDecoration.VERTICAL);
    dividerItemDecoration.setDrawable(getDrawable(R.drawable.divider));
    recyclerView.addItemDecoration(dividerItemDecoration);

Answer 1

我是通过以下方式完成的。

注意：在我的解决方案中，分隔符是项目视图的一部分，您可以设置背景或绘制线条，或添加底部边距并让空间显示背景因此创建分隔符等我推荐查看ItemDecoration api。我只是向您展示如何在ItemDecoration中确定您想要做什么。

首先，在适配器中：

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
    ...
    if (mData.get(postion) instanceof ObjectA)
        holder.itemView.setTag(R.id.noSpaceAfter, Boolean.TRUE);
    else
        holder.itemView.setTag(R.id.noSpaceAfter, Boolean.FALSE);
    ...
}

然后在RecyclerView中，声明ItemDecoration

mRecyclerView.addItemDecoration(new MyDividerItemDecoration());

最后，定义您的MyDividerItemDecorator

public class MyDividerItemDecoration extends RecyclerView.ItemDecoration {
    public MyDividerItemDecoration () {
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
                               RecyclerView.State state) {
        Boolean noSpace = (Boolean) view.getTag(R.id.noSpaceAfter);
        View v = view.findViewById(R.id.view_sep);
        if (v != null) {
            if (noSpace == null || !noSpace) {
                v.setVisibility(View.VISIBLE);
            } else {
                v.setVisibility(View.INVISIBLE);
            }
        }
    }
}

考虑到这一点，您只需复制DividerItemDecoration的来源，然后在其drawVertical方法中，当您在循环中获取视图时，请检查是否{{ 1}}是真或假，并相应地跳过绘图。

Answer 2

尝试在布局底部添加行xml文件并定义所需的layout_height并设置layout_width =“match_parent”并隐藏您想要的特定索引的视图

例如 -

`<View   
   android:id="@+id/view_divider"    
    android:layout_width="match_parent"    
    android:layout_height="@dimen/one"   
    android:background="@color/grey_divider_color"/>`

Answer 3

@Ali我喜欢你的解决方案。但是，您的代码需要布局中的分隔符。我通过隐藏常规分隔符来解决它。无论如何，谢谢你的提示。这是我的班级：

public class DividerItemDecoration extends RecyclerView.ItemDecoration {

private static final int[] ATTRS = new int[]{android.R.attr.listDivider};

private Drawable divider;

/**
 * Default divider will be used
 */
public DividerItemDecoration(Context context) {
    final TypedArray styledAttributes = context.obtainStyledAttributes(ATTRS);
    divider = styledAttributes.getDrawable(0);
    styledAttributes.recycle();
}

/**
 * Custom divider will be used
 */
public DividerItemDecoration(Context context, int resId) {
    divider = ContextCompat.getDrawable(context, resId);
}

@Override
public void onDraw(Canvas canvas, RecyclerView parent, RecyclerView.State state) {
    int left = parent.getPaddingLeft();
    int right = parent.getWidth() - parent.getPaddingRight();

    int childCount = parent.getChildCount();
    for (int i = 0; i < childCount; i++) {
        View row = parent.getChildAt(i);
        Boolean noDivider = (Boolean) row.getTag(R.id.noSpaceAfter);

        if (noDivider == null || !noDivider) {
            drawDivider(canvas, row, left, right);
        }
    }
}

private void drawDivider(Canvas canvas, View row, int left, int right) {
    RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) row.getLayoutParams();

    int top = row.getBottom() + params.bottomMargin;
    int bottom = top + divider.getIntrinsicHeight();

    divider.setBounds(left, top, right, bottom);
    divider.draw(canvas);
}

}