ios7的UITableView實現ios6的圓角效果

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
  if ([cell respondsToSelector:@selector(tintColor)]) {
    if (tableView == self.tableView) {
      CGFloat cornerRadius = 5.f;
      cell.backgroundColor = UIColor.clearColor;
      CAShapeLayer *layer = [[CAShapeLayer alloc] init];
      CGMutablePathRef pathRef = CGPathCreateMutable();
      CGRect bounds = CGRectInset(cell.bounds, 10, 0);
      BOOL addLine = NO;
      if (indexPath.row == 0 && indexPath.row == [tableView numberOfRowsInSection:indexPath.section]-1) {
        CGPathAddRoundedRect(pathRef, nil, bounds, cornerRadius, cornerRadius);
      } else if (indexPath.row == 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);
        CGPathAddLineToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMaxY(bounds));
        addLine = YES;
      } else if (indexPath.row == [tableView numberOfRowsInSection:indexPath.section]-1) {
        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);
        CGPathAddLineToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMinY(bounds));
      } else {
        CGPathAddRect(pathRef, nil, bounds);
        addLine = YES;
      }
      layer.path = pathRef;
      CFRelease(pathRef);
      layer.fillColor = [UIColor colorWithWhite:1.f alpha:0.8f].CGColor;

      if (addLine == YES) {
        CALayer *lineLayer = [[CALayer alloc] init];
        CGFloat lineHeight = (1.f / [UIScreen mainScreen].scale);
        lineLayer.frame = CGRectMake(CGRectGetMinX(bounds)+10, bounds.size.height-lineHeight, bounds.size.width-10, lineHeight);
        lineLayer.backgroundColor = tableView.separatorColor.CGColor;
        [layer addSublayer:lineLayer];
      }
      UIView *testView = [[UIView alloc] initWithFrame:bounds];
      [testView.layer insertSublayer:layer atIndex:0];
      testView.backgroundColor = UIColor.clearColor;
      cell.backgroundView = testView;
    }
  }
}