RecyclerView如何消除底部的分割线

Posted 2020-08-09 掌握当下

最近遇到一个问题，用RecyclerView显示数据，纵向列表显示，添加默认分割线。

 

问题是：底部也会显示分割线，这很影响美观。

 

怎么解决这个问题呢？我想了很多办法，毫无头绪。。。

 

最后，查看默认分割线的类DividerItemDecoration的源码：

public class DividerItemDecoration extends ItemDecoration {
    private static final int[] ATTRS = new int[]{16843284};
    public static final int HORIZONTAL_LIST = 0;
    public static final int VERTICAL_LIST = 1;
    private Drawable mDivider;
    private int mOrientation;

    public DividerItemDecoration(Context context, int orientation) {
        TypedArray a = context.obtainStyledAttributes(ATTRS);
        this.mDivider = a.getDrawable(0);
        a.recycle();
        this.setOrientation(orientation);
    }

    public void setOrientation(int orientation) {
        if(orientation != 0 && orientation != 1) {
            throw new IllegalArgumentException("invalid orientation");
        } else {
            this.mOrientation = orientation;
        }
    }

    public void onDraw(Canvas c, RecyclerView parent) {
        if(this.mOrientation == 1) {
            this.drawVertical(c, parent);
        } else {
            this.drawHorizontal(c, parent);
        }

    }

    public void drawVertical(Canvas c, RecyclerView parent) {
        int left = parent.getPaddingLeft();
        int right = parent.getWidth() - parent.getPaddingRight();
        int childCount = parent.getChildCount();

        for(int i = 0; i < childCount; ++i) {
            View child = parent.getChildAt(i);
            LayoutParams params = (LayoutParams)child.getLayoutParams();
            int top = child.getBottom() + params.bottomMargin;
            int bottom = top + this.mDivider.getIntrinsicHeight();
            this.mDivider.setBounds(left, top, right, bottom);
            this.mDivider.draw(c);
        }

    }

    public void drawHorizontal(Canvas c, RecyclerView parent) {
        int top = parent.getPaddingTop();
        int bottom = parent.getHeight() - parent.getPaddingBottom();
        int childCount = parent.getChildCount();

        for(int i = 0; i < childCount; ++i) {
            View child = parent.getChildAt(i);
            LayoutParams params = (LayoutParams)child.getLayoutParams();
            int left = child.getRight() + params.rightMargin;
            int right = left + this.mDivider.getIntrinsicHeight();
            this.mDivider.setBounds(left, top, right, bottom);
            this.mDivider.draw(c);
        }

    }

    public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
        if(this.mOrientation == 1) {
            outRect.set(0, 0, 0, this.mDivider.getIntrinsicHeight());
        } else {
            outRect.set(0, 0, this.mDivider.getIntrinsicWidth(), 0);
        }

    }
}

 

因为我用到的是垂直列表，用到的是红色字体处的代码：

 public void drawVertical(Canvas c, RecyclerView parent) {
        int left = parent.getPaddingLeft();
        int right = parent.getWidth() - parent.getPaddingRight();
        int childCount = parent.getChildCount();

        for(int i = 0; i < childCount; ++i) {
            View child = parent.getChildAt(i);
            LayoutParams params = (LayoutParams)child.getLayoutParams();
            int top = child.getBottom() + params.bottomMargin;
            int bottom = top + this.mDivider.getIntrinsicHeight();
            this.mDivider.setBounds(left, top, right, bottom);
            this.mDivider.draw(c);
        }

    }

从代码中很容易看出只要修改for循环中的内容就可去掉底部的分割线：

 public void drawVertical(Canvas c, RecyclerView parent) {
        int left = parent.getPaddingLeft();
        int right = parent.getWidth() - parent.getPaddingRight();
        int childCount = parent.getChildCount();

        for(int i = 0; i < childCount-1; ++i) {
            View child = parent.getChildAt(i);
            LayoutParams params = (LayoutParams)child.getLayoutParams();
            int top = child.getBottom() + params.bottomMargin;
            int bottom = top + this.mDivider.getIntrinsicHeight();
            this.mDivider.setBounds(left, top, right, bottom);
            this.mDivider.draw(c);
        }

    }

因为这个类我们不能直接修改，所以我们可以自定义一个类，修改相应内容，

添加分割线的时候，使用自定义类。

 

大功告成！！！