iOS 根據字元串數目，自定義Label等控制項的高度

利用分類，NSString，增加一個方法。

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
@interface NSString (Height)

+ (CGSize)getRect:(NSString *)textStr andWidth:(CGSize)size andFont:(UIFont *)font;

@end

#import "NSString+Height.h"

@implementation NSString (Height)

+ (CGSize)getRect:(NSString *)textStr andWidth:(CGSize)size andFont:(UIFont *)font
{
    
    CGRect rect = [textStr boundingRectWithSize:size options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:font} context:nil];
    
    return rect.size;
    
}

@end

使用：

CGSize size = [NSString getRect:str andWidth:CGSizeMake(IOS_SCREEN.size.width/2 - 10, CGFLOAT_MAX) andFont:[UIFont systemFontOfSize:14]];