RecyclerView添加下划线

添加下划线

public class MyDivider extends RecyclerView.ItemDecoration {
    private Paint mPaint;
    private Context context;
    private Drawable divider;
    private int mDividerHeight = 2;//分割线高度，默认为1px
    public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;
    public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;
    private int mOrientation;
    public static final int[] ATRRS = new int[]{
            android.R.attr.listDivider
    };
    /**
     * 自定义分割线
     *
     * @param context
     * @param orientation 列表方向
     * @param drawableId  分割线图片
     */
    public MyDivider(Context context, int orientation, int drawableId) {
        this(context, orientation);
        divider = ContextCompat.getDrawable(context, drawableId);
        mDividerHeight = divider.getIntrinsicHeight();
    }
    //获取分割线尺寸
    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        super.getItemOffsets(outRect, view, parent, state);
        outRect.set(0, 0, 0, mDividerHeight);
    }
    /**
     * 自定义分割线
     *
     * @param context
     * @param orientation   列表方向
     * @param dividerHeight 分割线高度
     * @param dividerColor  分割线颜色
     */
    public MyDivider(Context context, int orientation, int dividerHeight, int dividerColor) {
        this(context, orientation);
        mDividerHeight = dividerHeight;
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setColor(dividerColor);
        mPaint.setStyle(Paint.Style.FILL);
    }


    public MyDivider(Context context, int orientation) {
        this.context = context;
        final TypedArray ta = context.obtainStyledAttributes(ATRRS);
        this.divider = ta.getDrawable(0);
        ta.recycle();
        setOrientation(orientation);
    }

    //设置屏幕的方向
    public void setOrientation(int orientation) {
        if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
            throw new IllegalArgumentException("invalid orientation");
        }
        mOrientation = orientation;
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
        super.onDraw(c, parent, state);
        if (mOrientation == HORIZONTAL_LIST) {
            drawVertical(c, parent);
        } else {
            drawHorizontal(c, parent);
        }
    }

    //由于Divider也有宽高，每一个Item需要向下或者向右偏移
    @Override
    public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
        if (mOrientation == VERTICAL_LIST) {
            outRect.set(0, 0, 0, divider.getIntrinsicHeight());
        } else {
            outRect.set(0, 0, divider.getIntrinsicWidth(), 0);
        }
    }
    //绘制横向 item 分割线
    private void drawHorizontal(Canvas canvas, RecyclerView parent) {
        final int left = parent.getPaddingLeft();
        final int right = parent.getMeasuredWidth() - parent.getPaddingRight();
        final int childSize = parent.getChildCount();
        for (int i = 0; i < childSize; i++) {
            final View child = parent.getChildAt(i);
            RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();
            final int top = child.getBottom() + layoutParams.bottomMargin;
            final int bottom = top + mDividerHeight;

            if (divider != null) {
                divider.setBounds(left, top, right, bottom);
                divider.draw(canvas);
            }
            if (mPaint != null) {
                canvas.drawRect(left, top, right, bottom, mPaint);
            }
        }
    }

    //绘制纵向 item 分割线
    private void drawVertical(Canvas canvas, RecyclerView parent) {
        final int top = parent.getPaddingTop();
        final int bottom = parent.getMeasuredHeight() - parent.getPaddingBottom();
        final int childSize = parent.getChildCount();
        for (int i = 0; i < childSize; i++) {
            final View child = parent.getChildAt(i);
            RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();
            final int left = child.getRight() + layoutParams.rightMargin;
            final int right = left + mDividerHeight;
            if (divider != null) {
                divider.setBounds(left, top, right, bottom);
                divider.draw(canvas);
            }
            if (mPaint != null) {
                canvas.drawRect(left, top, right, bottom, mPaint);
            }
        }
    }
}

在activity里面

 recyclerView.addItemDecoration(new MyDivider(MainActivity.this, LinearLayoutManager.VERTICAL));

这样就可以了