給tableView的section設置圓角

-(void)setFrame:(CGRect)frame{
CGFloat margin = 10;
frame.origin.x = margin;
frame.size.width = SCREEN_WIDTH - margin*2;
[super setFrame:frame];
}
- 實現tableView的willDisplayCell方法,給section繪制圓角
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
if ([cell respondsToSelector:@selector(tintColor)]) {
if (tableView == self.tableView) {
// 圓角弧度半徑
CGFloat cornerRadius = 5.f;
// 設置cell的背景色為透明,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;
// 創建一個shapeLayer
CAShapeLayer *layer = [[CAShapeLayer alloc] init];
CAShapeLayer *backgroundLayer = [[CAShapeLayer alloc] init]; //顯示選中
// 創建一個可變的圖像Path句柄,該路徑用於保存繪圖信息
CGMutablePathRef pathRef = CGPathCreateMutable();
// 獲取cell的size
CGRect bounds = CGRectInset(cell.bounds, 0, 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
// 這里要判斷分組列表中的第一行,每組section的第一行,每組section的中間行
BOOL addLine = NO;
// CGPathAddRoundedRect(pathRef, nil, bounds, cornerRadius, cornerRadius);
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,設為p1,(CGRectGetMinX(bounds), CGRectGetMinY(bounds))為左上角的點,設為p1(x1,y1),(CGRectGetMidX(bounds), CGRectGetMinY(bounds))為頂部中點的點,設為p2(x2,y2)。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,則在兩條直線相交處繪制弧度為r的圓角。
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域了
CGPathAddLineToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMaxY(bounds));
addLine = YES;
} 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,終點坐標為右下角坐標點並放到路徑中去
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);
addLine = YES;
}
// 把已經繪制好的可變圖像路徑賦值給圖層,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,類似於渲染render
// layer.fillColor = [UIColor colorWithWhite:1.f alpha:0.8f].CGColor;
layer.fillColor = [UIColor whiteColor].CGColor;
// 添加分隔線圖層
if (addLine == YES) {
CALayer *lineLayer = [[CALayer alloc] init];
CGFloat lineHeight = (1.f / [UIScreen mainScreen].scale);
lineLayer.frame = CGRectMake(CGRectGetMinX(bounds), bounds.size.height-lineHeight, bounds.size.width, lineHeight);
// 分隔線顏色取自於原來tableview的分隔線顏色
lineLayer.backgroundColor = tableView.separatorColor.CGColor;
[layer addSublayer:lineLayer];
}
// 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.selectedBackgroundView = roundView;
cell.backgroundView = roundView;
//以上方法存在缺陷當點擊cell時還是出現cell方形效果,因此還需要添加以下方法
UIView *selectedBackgroundView = [[UIView alloc] initWithFrame:bounds];
backgroundLayer.fillColor = tableView.separatorColor.CGColor;
[selectedBackgroundView.layer insertSublayer:backgroundLayer atIndex:0];
selectedBackgroundView.backgroundColor = UIColor.clearColor;
cell.selectedBackgroundView = selectedBackgroundView;
}
}
}