- [__ NSCFString boundingRectWithSize:options:attributes:context:]:发送到实例的无法识别的选择器

Question

@interface PromotionsListViewController : UITableViewController 
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"PromotionCell";
PromotionCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
    cell = [[PromotionCell alloc] init];
}

// Configure the cell...
Promotion *promotion = [self.promotionList objectAtIndex:indexPath.row];

[cell.imgView setImageWithURL:[NSURL URLWithString:promotion.imageURL] placeholderImage:[UIImage imageNamed:@""]];
cell.lblTitle.text = promotion.promotionTitle;

return cell;
}
@interface PromotionCell : UITableViewCell

@property(nonatomic, strong) UIImageView *imgView;
@property(nonatomic, strong) UILabel *lblTitle;

@end
- (void)layoutSubviews {

if (self.lblTitle.text) {

    CGSize maxsize = CGSizeMake(300, CGFLOAT_MAX);
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    paragraphStyle.lineBreakMode = NSLineBreakByWordWrapping;

    CGRect calculateRect = [_lblTitle.text boundingRectWithSize:maxsize options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:_lblTitle.font, NSParagraphStyleAttributeName:paragraphStyle.copy} context:nil];

    _lblTitle.frame = CGRectMake(_lblTitle.frame.origin.x, 300 - calculateRect.size.height - 5, _lblTitle.frame.size.width, calculateRect.size.height);

} else {
    _lblTitle.frame = CGRectZero;
}
}
- (UILabel *)lblTitle {

if (!_lblTitle) {

    _lblTitle = [[UILabel alloc] initWithFrame:CGRectMake(10, 250, 300, 50)];
    _lblTitle.font = [UIFont boldSystemFontOfSize:22.0f];
    _lblTitle.numberOfLines = 0;
    _lblTitle.lineBreakMode = NSLineBreakByWordWrapping;
    [self.contentView addSubview:_lblTitle];
}
return _lblTitle;
}

任何人都可以告诉我,我做错了什么？我希望我的问题很清楚..

Answer 1

我也有这个问题.原来有两种类似的方法boundingRectWithSize:.一个为NSString一个为一个NSAttributedString.

适用于iOS 6及更高版本的NSAttributedString的以下内容:

- (CGRect)boundingRectWithSize:(CGSize)size options:(NSStringDrawingOptions)options context:(NSStringDrawingContext *)context

另一个NSString方法(您当前正在使用)仅适用于iOS 7:

- (CGRect)boundingRectWithSize:(CGSize)size options:(NSStringDrawingOptions)options attributes:(NSDictionary *)attributes context:(NSStringDrawingContext *)context

因此,只需在Attributed String上调用boundingRectWithSize:方法而不需要额外的Attributes:字段,它就可以在iOS 6上正常工作.