iOS 全局修改字体

全局修改Lable/Button字体

　　本次版本需求要把原来的字体全改掉，由于项目中有的是代码创建的，有的是XIB中直接改的，一个一个改工作量太大，使用运行时可以很轻松的实现
 
     首先，项目中大多数设置字体的控件有 Lable， Button等，控件的初始化，有三种方式，init，initWithFrame，awakeFromNib
     所以，使用运行时替换这三个方法就可以了。
 
     为方便在多个类中使用运行时交换方法，可以创建一个头文件 SwizzlingExchange.h ，实现我们需要的交换方法
 SwizzlingExchange:

#ifndef SwizzlingExchange_h
#define SwizzlingExchange_h
#import <objc/runtime.h>

static inline void swizzling_exchangeMethod(Class clazz, SEL originalSelector, SEL swizzledSelector) {
Method originalMethod = class_getInstanceMethod(clazz, originalSelector);
Method swizzledMethod = class_getInstanceMethod(clazz, swizzledSelector);

BOOL success = class_addMethod(clazz, originalSelector, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod));

if (success) {
class_replaceMethod(clazz, swizzledSelector, method_getImplementation(originalMethod), method_getTypeEncoding(originalMethod));
} else {
method_exchangeImplementations(originalMethod, swizzledMethod);
}
}

#endif /* SwizzlingExchange_h */

 
 
     然后创建我们 Lable、Button等控件的分类，在 +load方法里面 交换我们的三个函数，这样我们首次创建的控件字体就是我们的默认字体，对于某些特殊的地方使用的不是默认字体，重新设置字体就可以了。
 Lable

//
//  UILabel+ChangeFont.m
//  DFRomwe
//
//  Created by 王卫亮 on 16/7/13.
//  Copyright © 2016年 heyan. All rights reserved.
//

#import "UILabel+ChangeFont.h"
#import "SwizzlingExchange.h"

#define kLableFont @"Snell Roundhand"  // 测试字体，容易看出来有没有全改掉

@implementation UILabel (ChangeFont)

+(void)load {
//只执行一次这个方法
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
swizzling_exchangeMethod([self class], @selector(init), @selector(myInit));
swizzling_exchangeMethod([self class], @selector(initWithFrame:), @selector(myInitWithFrame:));
swizzling_exchangeMethod([self class], @selector(awakeFromNib), @selector(myAwakeFromNib));
});
}

- (instancetype)myInit {
id __self = [self myInit];
UIFont * font = [UIFont fontWithName:DefaultFont size: self.font.pointSize];
if (font) {
self.font = font;
}
return __self;
}

- (instancetype)myInitWithFrame:(CGRect)rect {
id __self = [self myInitWithFrame: rect];
UIFont * font = [UIFont fontWithName:DefaultFont size: self.font.pointSize];
if (font) {
self.font = font;
}
return __self;
}

- (void)myAwakeFromNib {
[self myAwakeFromNib];
UIFont * font = [UIFont fontWithName:DefaultFont size: self.font.pointSize];
if (font) {
self.font = font;
}
}

@end

Button:

//
//  UIButton+ChangeFont.m
//  DFRomwe
//
//  Created by 王卫亮 on 16/7/13.
//  Copyright © 2016年 heyan. All rights reserved.
//

#import "UIButton+ChangeFont.h"
#import "SwizzlingExchange.h"

#define kLableFont @"Snell Roundhand"  // 测试字体，容易看出来有没有全改掉

@implementation UIButton (ChangeFont)

+(void)load {
//只执行一次这个方法
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
swizzling_exchangeMethod([self class], @selector(init), @selector(myInit));
swizzling_exchangeMethod([self class], @selector(initWithFrame:), @selector(myInitWithFrame:));
swizzling_exchangeMethod([self class], @selector(awakeFromNib), @selector(myAwakeFromNib));
});
}

- (instancetype)myInit {

id __self = [self myInit];
UIFont * font = [UIFont fontWithName:DefaultFont size: self.titleLabel.font.pointSize];
if (font) {
self.titleLabel.font = font;
}
return __self;
}

- (instancetype)myInitWithFrame:(CGRect)rect {
id __self = [self myInitWithFrame:rect];
UIFont * font = [UIFont fontWithName:DefaultFont size: self.titleLabel.font.pointSize];
if (font) {
self.titleLabel.font = font;
}
return __self;
}

- (void)myAwakeFromNib {
[self myAwakeFromNib];
UIFont * font = [UIFont fontWithName:DefaultFont size: self.titleLabel.font.pointSize];
if (font) {
self.titleLabel.font = font;
}
}

@end