iOS中默認的UILabel是垂直居中對齊的，如果UILabel設置的高度較大，當內容少的時候，會自動垂直居中。

創建一個 UILabel的category

代碼如下：

 

 
#import 

@interface UILabel (LeftTopAlign)
- (void) textLeftTopAlign;
@end
 

 
 #import UILabel+LeftTopAlign.h

@implementation UILabel (LeftTopAlign)

- (void) textLeftTopAlign
{
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc]init];
    paragraphStyle.lineBreakMode = NSLineBreakByWordWrapping;
    
    NSDictionary *attributes = @{NSFontAttributeName:[UIFont systemFontOfSize:12.f], NSParagraphStyleAttributeName:paragraphStyle.copy};
    
    CGSize labelSize = [self.text boundingRectWithSize:CGSizeMake(207, 999) options:NSStringDrawingUsesLineFragmentOrigin attributes:attributes context:nil].size;
    
    CGRect dateFrame =CGRectMake(2, 140, CGRectGetWidth(self.frame)-5, labelSize.height);
    self.frame = dateFrame;
}
@end
  

 

在需要的時候，只需要直接調用即可。

 

 
#import UILabel+LeftTopAlign.h
-(void)someMethod:(UILabel*)label
{ 
  [label textLeftTopAlign];
}