iOS中默認(rèn)的UILabel是垂直居中對齊的，如果UILabel設(shè)置的高度較大，當(dāng)內(nèi)容少的時候，會自動垂直居中。

創(chuàng)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(diào)用即可。

#import UILabel+LeftTopAlign.h

-(void)someMethod:(UILabel*)label

{

[label textLeftTopAlign];

}