Question

ios7.0文字自适应 boundingRectWithSize 总是返回错误rect

图为我用两个函数做的测试,这是算出size重新设置frame后的结果
蓝色的是用
- (CGRect)boundingRectWithSize:(CGSize)size options:(NSStringDrawingOptions)options attributes:(NSDictionary *)attributes context:(NSStringDrawingContext *)context
不能返回正确的size

红色的使用
- (CGSize)sizeWithFont:(UIFont *)font constrainedToSize:(CGSize)size lineBreakMode:(NSLineBreakMode)lineBreakMode
能返回正确size

两个label用的字符串是同一个 ，有高手解释下并给个正确代码吗?

Answer 1

- (CGRect)boundingRectWithSize:(CGSize)size options:(NSStringDrawingOptions)options attributes:(NSDictionary *)attributes
是新的函数,你需要设置attributes相关属性.例如:

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc]init];
paragraphStyle.lineBreakMode = NSLineBreakByWordWrapping;
NSDictionary *attributes = @{NSFontAttributeName:label.font, NSParagraphStyleAttributeName:paragraphStyle.copy};

labelSize = [someText boundingRectWithSize:CGSizeMake(207, 999) options:NSStringDrawingUsesLineFragmentOrigin attributes:attributes context:nil].size;