ios 运行时特征，动态改变控件字体大小

需求：ex: 在不同尺寸的iPhone上面显示的字体大小不一样

https://github.com/rentzsch/jrswizzle

#import <UIKit/UIKit.h>

@interface UILabel (Common)
- (void) swizzSetFont: (UIFont *) font;
@end

#import "UILabel+Common.h"

@implementation UILabel (Common)
-(void)swizzSetFont:(UIFont *)font {
    //添加对手机尺寸的判断（省略）
    if ([self isMemberOfClass:[UILabel class]]) { //条件判断,只修改UILabel, 并且字体大小为33的
          NSLog(@"font=%@",font);
        if (font == [UIFont systemFontOfSize:]) {
            [self swizzSetFont:[UIFont systemFontOfSize:]];
        }
  

NSError * error = nil;

    [UILabel jr_swizzleMethod:@selector(swizzSetFont:) withMethod:@selector(setFont:) error: &error];

    NSLog(@"error=%@",error);