方法一

iOS UITableView section圓角陰影
如果自定義的cell底部有線棍好，則不適合此方法。
距底部有個5pt的偏移丘侠。UIEdgeInsetsMake(0, 0, 5, 0)

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
    // 圓角角度
    CGFloat radius = 4.f;
    // 設置cell 背景色為透明
    cell.backgroundColor = UIColor.clearColor;
    cell.contentView.backgroundColor = UIColor.clearColor;
    // 創(chuàng)建兩個layer
    CAShapeLayer *normalLayer = [[CAShapeLayer alloc] init];
    CAShapeLayer *selectLayer = [[CAShapeLayer alloc] init];
    // 獲取顯示區(qū)域大小
    CGRect bounds = CGRectInset(cell.bounds, 0, 0);
    // cell的backgroundView
    UIView *normalBgView = [[UIView alloc] initWithFrame:bounds];
    // 獲取每組行數
    NSInteger rowNum = [tableView numberOfRowsInSection:indexPath.section];
    // 貝塞爾曲線
    UIBezierPath *bezierPath = nil;
    
    if (rowNum == 1) {
        // 一組只有一行（四個角全部為圓角）
        bezierPath = [UIBezierPath bezierPathWithRoundedRect:bounds byRoundingCorners:UIRectCornerAllCorners cornerRadii:CGSizeMake(radius, radius)];
        normalBgView.clipsToBounds = NO;
    }else {
        normalBgView.clipsToBounds = YES;
        if (indexPath.row == 0) {
            normalBgView.frame = UIEdgeInsetsInsetRect(bounds, UIEdgeInsetsMake(-5, 0, 0, 0));
            CGRect rect = UIEdgeInsetsInsetRect(bounds, UIEdgeInsetsMake(5, 0, 0, 0));
            // 每組第一行（添加左上和右上的圓角）
            bezierPath = [UIBezierPath bezierPathWithRoundedRect:rect byRoundingCorners:(UIRectCornerTopLeft|UIRectCornerTopRight) cornerRadii:CGSizeMake(radius, radius)];
        }else if (indexPath.row == rowNum - 1) {
            normalBgView.frame = UIEdgeInsetsInsetRect(bounds, UIEdgeInsetsMake(0, 0, -5, 0));
            CGRect rect = UIEdgeInsetsInsetRect(bounds, UIEdgeInsetsMake(0, 0, 5, 0));
            // 每組最后一行（添加左下和右下的圓角）
            bezierPath = [UIBezierPath bezierPathWithRoundedRect:rect byRoundingCorners:(UIRectCornerBottomLeft|UIRectCornerBottomRight) cornerRadii:CGSizeMake(radius, radius)];
        }else {
            // 每組不是首位的行不設置圓角
            bezierPath = [UIBezierPath bezierPathWithRect:bounds];
        }
    }
    
    // 陰影
    normalLayer.shadowColor = [UIColor blackColor].CGColor;
    normalLayer.shadowOpacity = 0.2;
    normalLayer.shadowOffset = CGSizeMake(0, 0);
    normalLayer.path = bezierPath.CGPath;
    normalLayer.shadowPath = bezierPath.CGPath;
    
    // 把已經繪制好的貝塞爾曲線路徑賦值給圖層惭嚣，然后圖層根據path進行圖像渲染render
    normalLayer.path = bezierPath.CGPath;
    selectLayer.path = bezierPath.CGPath;
    
    // 設置填充顏色
    normalLayer.fillColor = [UIColor whiteColor].CGColor;
    // 添加圖層到nomarBgView中
    [normalBgView.layer insertSublayer:normalLayer atIndex:0];
    normalBgView.backgroundColor = UIColor.clearColor;
    cell.backgroundView = normalBgView;
    
    // 替換cell點擊效果
    UIView *selectBgView = [[UIView alloc] initWithFrame:bounds];
    selectLayer.fillColor = [UIColor colorWithWhite:0.95 alpha:1.0].CGColor;
    [selectBgView.layer insertSublayer:selectLayer atIndex:0];
    selectBgView.backgroundColor = UIColor.clearColor;
    cell.selectedBackgroundView = selectBgView;
}

方法二

http://www.reibang.com/p/92662061c0dc

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath{
    [self shearTableViewSection:cell tableView:tableView IndexPath:indexPath cornerRadius:4 width:0];
}
#pragma mark TableView Section 切圓角
- (void)shearTableViewSection:(UITableViewCell *)cell tableView:(UITableView *)tableView IndexPath:(NSIndexPath *)indexPath cornerRadius:(CGFloat)radius width:(CGFloat)width
{
    // 圓角弧度半徑
    CGFloat cornerRadius = 0.f;
    if (radius == 0) {
        cornerRadius = 10.f;
    }else{
        cornerRadius = radius;
    }
    
    // 設置cell的背景色為透明饭望，如果不設置這個的話，則原來的背景色不會被覆蓋
    cell.backgroundColor = UIColor.clearColor;
    cell.contentView.backgroundColor = UIColor.clearColor;
    
    // 創(chuàng)建一個shapeLayer
    CAShapeLayer *layer = [[CAShapeLayer alloc] init];
    CAShapeLayer *backgroundLayer = [[CAShapeLayer alloc] init]; //顯示選中
    // 創(chuàng)建一個可變的圖像Path句柄澈侠，該路徑用于保存繪圖信息
    CGMutablePathRef pathRef = CGPathCreateMutable();
    // 獲取cell的size
    // 第一個參數,是整個 cell 的 bounds, 第二個參數是距左右兩端的距離,第三個參數是距上下兩端的距離
    CGRect bounds;
    bounds = CGRectInset(cell.bounds, width, 0);
    
    // CGRectGetMinY：返回對象頂點坐標
    // CGRectGetMaxY：返回對象底點坐標
    // CGRectGetMinX：返回對象左邊緣坐標
    // CGRectGetMaxX：返回對象右邊緣坐標
    // CGRectGetMidX: 返回對象中心點的X坐標
    // CGRectGetMidY: 返回對象中心點的Y坐標
    
    // 這里要判斷分組列表中的第一行劫侧，每組section的第一行，每組section的中間行
    
    // CGPathAddRoundedRect(pathRef, nil, bounds, cornerRadius, cornerRadius);
    
    if ([tableView numberOfRowsInSection:indexPath.section]-1 == 0) {
        CGPathMoveToPoint(pathRef, nil, CGRectGetMinX(bounds), CGRectGetMaxY(bounds));
        CGPathAddArcToPoint(pathRef, nil, CGRectGetMinX(bounds), CGRectGetMinY(bounds), CGRectGetMidX(bounds), CGRectGetMinY(bounds), cornerRadius);
        CGPathAddArcToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMinY(bounds), CGRectGetMaxX(bounds), CGRectGetMidY(bounds), cornerRadius);
        CGPathAddArcToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMaxY(bounds), CGRectGetMidX(bounds), CGRectGetMaxY(bounds), cornerRadius);
        CGPathAddArcToPoint(pathRef, nil, CGRectGetMinX(bounds), CGRectGetMaxY(bounds), CGRectGetMinX(bounds), CGRectGetMidY(bounds), cornerRadius);
        CGPathAddLineToPoint(pathRef, nil, CGRectGetMinX(bounds), CGRectGetMaxY(bounds));
        
        
    }else if (indexPath.row == 0) {
        // 初始起點為cell的左下角坐標
        CGPathMoveToPoint(pathRef, nil, CGRectGetMinX(bounds), CGRectGetMaxY(bounds));
        // 起始坐標為左下角埋涧，設為p板辽，（CGRectGetMinX(bounds), CGRectGetMinY(bounds)）為左上角的點奇瘦，設為p1(x1,y1)，(CGRectGetMidX(bounds), CGRectGetMinY(bounds))為頂部中點的點劲弦，設為p2(x2,y2)耳标。然后連接p1和p2為一條直線l1，連接初始點p到p1成一條直線l邑跪，則在兩條直線相交處繪制弧度為r的圓角次坡。
        CGPathAddArcToPoint(pathRef, nil, CGRectGetMinX(bounds), CGRectGetMinY(bounds), CGRectGetMidX(bounds), CGRectGetMinY(bounds), cornerRadius);
        CGPathAddArcToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMinY(bounds), CGRectGetMaxX(bounds), CGRectGetMidY(bounds), cornerRadius);
        // 終點坐標為右下角坐標點，把繪圖信息都放到路徑中去,根據這些路徑就構成了一塊區(qū)域了
        CGPathAddLineToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMaxY(bounds));
        
    } else if (indexPath.row == [tableView numberOfRowsInSection:indexPath.section]-1) {
        
        // 初始起點為cell的左上角坐標
        CGPathMoveToPoint(pathRef, nil, CGRectGetMinX(bounds), CGRectGetMinY(bounds));
        CGPathAddArcToPoint(pathRef, nil, CGRectGetMinX(bounds), CGRectGetMaxY(bounds), CGRectGetMidX(bounds), CGRectGetMaxY(bounds), cornerRadius);
        CGPathAddArcToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMaxY(bounds), CGRectGetMaxX(bounds), CGRectGetMidY(bounds), cornerRadius);
        // 添加一條直線画畅，終點坐標為右下角坐標點并放到路徑中去
        CGPathAddLineToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMinY(bounds));
    } else {
        
        // 添加cell的rectangle信息到path中（不包括圓角）
        CGPathAddRect(pathRef, nil, bounds);
    }
    // 把已經繪制好的可變圖像路徑賦值給圖層砸琅，然后圖層根據這圖像path進行圖像渲染render
    layer.path = pathRef;
    backgroundLayer.path = pathRef;
    // 注意：但凡通過Quartz2D中帶有creat/copy/retain方法創(chuàng)建出來的值都必須要釋放
    CFRelease(pathRef);
    // 按照shape layer的path填充顏色，類似于渲染render
    // layer.fillColor = [UIColor colorWithWhite:1.f alpha:0.8f].CGColor;
    layer.fillColor = [UIColor whiteColor].CGColor;
    
    
    // view大小與cell一致
    UIView *roundView = [[UIView alloc] initWithFrame:bounds];
    // 添加自定義圓角后的圖層到roundView中
    [roundView.layer insertSublayer:layer atIndex:0];
    roundView.backgroundColor = UIColor.clearColor;
    // cell的背景view
    cell.backgroundView = roundView;
}

iOS tableview整個Section切圓角

iOS tableview整個Section切圓角

方法一

方法二