运用shapeLayer 和 贝塞尔曲线 绘制圆角和阴影
- (void)tableView:(UITableView*)tableView willDisplayCell:(UITableViewCell*)cell forRowAtIndexPath:(NSIndexPath*)indexPath{
// 圆角弧度半径
CGFloatcornerRadius =5.f;
// 设置cell的背景色为透明，如果不设置这个的话，则原来的背景色不会被覆盖
self.backgroundColor = UIColor.clearColor;
// 创建一个shapeLayer
CAShapeLayer *layer = [[CAShapeLayer alloc] init];
CAShapeLayer *backgroundLayer = [[CAShapeLayer alloc] init]; //显示选中
// 创建一个可变的图像Path句柄，该路径用于保存绘图信息
CGMutablePathRef pathRef = CGPathCreateMutable();
// 获取cell的size
// 第一个参数,是整个 cell 的 bounds, 第二个参数是距左右两端的距离,第三个参数是距上下两端的距离
CGRect bounds = CGRectInset(self.bounds, 20, 0);
if(indexPath.row==0) {//第一个cell
if([tableViewnumberOfRowsInSection:indexPath.section] ==1) {//section 只有一个cell
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{
// 初始起点为cell的左下角坐标
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);
// 终点坐标为右下角坐标点，把绘图信息都放到路径中去,根据这些路径就构成了一块区域了
CGPathAddLineToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMaxY(bounds));
}
}elseif(indexPath.row== [tableViewnumberOfRowsInSection:indexPath.section]-1) {//最后一个cell
// 初始起点为cell的左上角坐标
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);
// 添加一条直线，终点坐标为右下角坐标点并放到路径中去
CGPathAddLineToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMinY(bounds));
}else{
// 添加cell的rectangle信息到path中（不包括圆角）
CGPathAddRect(pathRef,nil, bounds);
}
// 把已经绘制好的可变图像路径赋值给图层，然后图层根据这图像path进行图像渲染render
layer.path= pathRef;
backgroundLayer.path= pathRef;
// 注意：但凡通过Quartz2D中带有creat/copy/retain方法创建出来的值都必须要释放
CFRelease(pathRef);
// 按照shape layer的path填充颜色，类似于渲染render
// layer.fillColor = [UIColor colorWithWhite:1.f alpha:0.8f].CGColor;
layer.fillColor = [UIColor whiteColor].CGColor;
// view大小与cell一致
UIView*roundView = [[UIViewalloc]initWithFrame:bounds];
// 添加自定义圆角后的图层到roundView中
[roundView.layer insertSublayer:layer atIndex:0];
roundView.backgroundColor = UIColor.clearColor;
// cell的背景view
self.backgroundView= roundView;
// 给section加阴影
BOOLisFirstRow = !indexPath.row;// 第一个cell
BOOLisLastRow = (indexPath.row== [tableViewnumberOfRowsInSection:indexPath.section] -1);//最后一个cell
BOOLisSectionOneRow = ([tableViewnumberOfRowsInSection:indexPath.section] ==1);// 只有一个cell
// the shadow rect determines the area in which the shadow gets drawn
CGRect shadowRect = CGRectInset(CGRectMake(0, 0, kScreen_Width, self.frame.size.height), 20, -10);
if(isFirstRow)
shadowRect.origin.y+=10;
elseif(isLastRow)
shadowRect.size.height-=10;
// the mask rect ensures that the shadow doesn't bleed into other table cells
CGRect maskRect = CGRectInset(CGRectMake(0, 0, kScreen_Width, self.frame.size.height), -20, 0);
if(isFirstRow) {
maskRect.origin.y-=10;
maskRect.size.height+=10;
}
elseif(isLastRow)
maskRect.size.height+=10;
// 如果section 只有一个cell
if(isSectionOneRow) {
for(inti =0; i <2; i++) {
shadowRect.size.height-=10;
maskRect.size.height+=2.5;
}
}
// now configure the background view layer with the shadow
CALayer *layers = self.backgroundView.layer;
layers.shadowColor = SecondTextColor.CGColor;
layers.shadowOffset = CGSizeMake(0, 0);
layers.shadowRadius=2.5;
layers.shadowOpacity=0.2f;
layers.shadowPath = [UIBezierPath bezierPathWithRoundedRect:shadowRect cornerRadius:5].CGPath;
layers.masksToBounds=NO;
// and finally add the shadow mask
CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.path = [UIBezierPath bezierPathWithRect:maskRect].CGPath;
layers.mask= maskLayer;
}
为了减少代码写了一个分类直接导入项目，
[cell addShadowToSectionTableView:tableView atIndexPath:indexPath];
[cell addShadowToCellInTableView:tableView atIndexPath:indexPath];
代码地址： https://github.com/WWally/CSTableViewCell