ios开发之--使用UILabel Category 计算UILabel内容大小

在此仅做记录，代码如下：

.h

#import <UIKit/UIKit.h>

@interface UILabel (BoundingSize)

- (CGSize)boundingRectWithSize:(CGSize)size;

@end

.m

#import "UILabel+BoundingSize.h"

@implementation UILabel (BoundingSize)

- (CGSize)boundingRectWithSize:(CGSize)size

{

    NSDictionary *attribute = @{NSFontAttributeName: self.font};

    CGSize retSize = [self.text boundingRectWithSize:size

                                             options:\

                      NSStringDrawingTruncatesLastVisibleLine |

                      NSStringDrawingUsesLineFragmentOrigin |

                      NSStringDrawingUsesFontLeading

                                          attributes:attribute

                                             context:nil].size;

    return retSize;

}

@end

下面代码可供测试：

// 字符串

    NSString *str = @"北国风光，千里冰封，万里雪飘。望长城内外，惟余莽莽；大河上下，顿失滔滔。山舞银蛇，原驰蜡象，欲与天公试比高。须晴日，看红装素裹，分外妖娆。江山如此多娇，引无数英雄竞折腰。惜秦皇汉武，略输文采；唐宗宋祖，稍逊风骚。北国风光，千里冰封，万里雪飘。望长城内外，惟余莽莽；大河上下，顿失滔滔。山舞银蛇，原驰蜡象，欲与天公试比高。须晴日，看红装素裹，分外妖娆。江山如此多娇，引无数英雄竞折腰。惜秦皇汉武，略输文采；唐宗宋祖，稍逊风骚。北国风光，千里冰封，万里雪飘。望长城内外，惟余莽莽；大河上下，顿失滔滔。山舞银蛇，原驰蜡象，欲与天公试比高。须晴日，看红装素裹，分外妖娆。江山如此多娇，引无数英雄竞折腰。惜秦皇汉武，略输文采；唐宗宋祖，稍逊风骚。";

    // 初始化label

    UILabel *label = [UILabel new];

    label.backgroundColor = [UIColor whiteColor];

    [self.view addSubview:label];

    // label获取字符串

    label.text = str;

    // label获取字体

    label.font = [UIFont systemFontOfSize:18.0f];

    // 根据获取到的字符串以及字体计算label需要的size

    CGSize size = [label boundingRectWithSize:CGSizeMake([UIScreen mainScreen].bounds.size.width, )];

    // 设置无限换行

    label.numberOfLines = ;

    // 设置label的frame

    label.frame = CGRectMake(0.0f, 50.0f, size.width, size.height);

效果如下：

还有一种方法，话不多说，直接上代码：

.h

#import <Foundation/Foundation.h>

#import <UIKit/UIKit.h>

@interface NSString (Extension)

-(CGFloat)heightWithWidth:(CGFloat)width font:(CGFloat)font;

@end

.m

#import "NSString+Extension.h"

@implementation NSString (Extension)

-(CGFloat)heightWithWidth:(CGFloat)width font:(CGFloat)font{

    UIFont * fonts = [UIFont systemFontOfSize:font];

    CGSize size  = CGSizeMake(width, 100000.0);

    NSDictionary * dict  = [NSDictionary dictionaryWithObjectsAndKeys:fonts,NSFontAttributeName ,nil];

    size = [self boundingRectWithSize:size options:NSStringDrawingUsesLineFragmentOrigin attributes:dict context:nil].size;

    return size.height;

}

@end

调用：

UILabel *contentLabel = [[UILabel alloc]init];

contentLabel.numberOfLines = ;

[self.view addSubview:_contentLabel];

CGFloat contentHeight = [contentLabel.text heightWithWidth:CGRectGetWidth(self.contentView.bounds) -  font:];

_contentLabel.frame = CGRectMake(, CGRectGetMaxY(self.view.frame) + , CGRectGetWidth(self.view.bounds) - , contentHeight);

最后贡献个工具类：

.h

#import <Foundation/Foundation.h>

#import <UIKit/UIKit.h>

@interface GlobalUI : NSObject

+ (UIImageView *)createImageViewbgColor:(UIColor *)bgColor;

+ (UILabel *)createLabelFont:(CGFloat )fontsize titleColor:(UIColor *)titleColor bgColor:(UIColor *)bgColor;

+ (UIButton *)createButtonWithImg:(UIImage *)img title:(NSString *)title titleColor:(UIColor *)titleColor;

@end

.m

#import "GlobalUI.h"

@implementation GlobalUI

+ (UIImageView *)createImageViewbgColor:(UIColor *)bgColor {

    UIImageView * img = [[UIImageView alloc] init];

    img.backgroundColor = bgColor;

    return img;

}

+ (UILabel *)createLabelFont:(CGFloat )fontsize titleColor:(UIColor *)titleColor bgColor:(UIColor *)bgColor{

    UILabel * lab = [[UILabel alloc]init];

    lab.font = [UIFont systemFontOfSize:fontsize];

    lab.textColor = titleColor;

    lab.backgroundColor = bgColor;

    return  lab;

}

+ (UIButton *)createButtonWithImg:(UIImage *)img title:(NSString *)title titleColor:(UIColor *)titleColor{

    UIButton * btn = [UIButton buttonWithType:UIButtonTypeCustom];

    [btn setImage:img forState:UIControlStateNormal];

    [btn setTitle:title forState:UIControlStateNormal];

    [btn  setTitleColor:titleColor forState:UIControlStateNormal];

     return  btn;

}

@end

其实类别真的很方便，虽然不太灵活和有局限性，不过实际写代码过程中，真的很方便，还有很多用法，如果写的不好，或者有更好的方法，请在下方评论！