ios 交换方法

1.类/分类添加方法后交换

[[Person alloc] eat];
[[Person alloc] swizzleEat];
[[Person alloc] eat];

- (void)eat {
    NSLog(@"吃蔬菜");
}

- (void)swizzle_eat {
    NSLog(@"吃水果");
}

- (void)swizzleEat {
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        Method eatMethod = class_getInstanceMethod([self class], @selector(eat));
        Method swizzleEatMethod = class_getInstanceMethod([self class], @selector(swizzle_eat));
        BOOL addSucceed = class_addMethod([self class], @selector(swizzle_eat), method_getImplementation(swizzleEatMethod), method_getTypeEncoding(eatMethod));
        if (addSucceed) {
            class_replaceMethod([self class], @selector(swizzle_eat), method_getImplementation(eatMethod), method_getTypeEncoding(eatMethod));
        }else {
            method_exchangeImplementations(eatMethod, swizzleEatMethod);
        }
    });
}

结果：

2022-01-10 21:19:15.211439+0800 TestDemo[27126:498987] 吃蔬菜
2022-01-10 21:19:15.211748+0800 TestDemo[27126:498987] 吃水果

2.创建并交换实例方法

[[Person alloc] eat];

Class class = [Person class];
SEL selector = @selector(eat);
SEL swizzledSelector = NSSelectorFromString(@"eat_meet");
Method originEat = class_getInstanceMethod(class, selector);
void (^swizzleBlock)(void) = ^(void) {
     NSLog(@"吃火锅");
};
IMP swizzleIMP = imp_implementationWithBlock(swizzleBlock);
class_addMethod(class, swizzledSelector, swizzleIMP, method_getTypeEncoding(originEat));
Method swizzleMethod = class_getInstanceMethod(class, swizzledSelector);
method_exchangeImplementations(originEat, swizzleMethod); 
[[Person alloc] eat];

结果：

2022-01-10 21:18:02.564029+0800 TestDemo[27076:497657] 吃蔬菜
2022-01-10 21:18:02.564333+0800 TestDemo[27076:497657] 吃火锅

3.创建并交换类方法

+ (void)run {
    NSLog(@"慢步");
}

[Person run];
SEL runSelector = @selector(run);
SEL runSwizzledSelector = NSSelectorFromString(@"run_quick");
Method runOrigin = class_getClassMethod(class, runSelector);
void (^runSwizzleBlock)(void) = ^(void) {
   NSLog(@"快跑");
};
IMP runSwizzleIMP = imp_implementationWithBlock(runSwizzleBlock);
class_addMethod(object_getClass([Person class]), runSwizzledSelector, runSwizzleIMP, method_getTypeEncoding(runOrigin));
Method runSwizzleMethod = class_getClassMethod(class, runSwizzledSelector);
method_exchangeImplementations(runOrigin, runSwizzleMethod);    [Person run];

结果：

2022-01-10 21:18:02.564458+0800 TestDemo[27076:497657] 慢步
2022-01-10 21:18:02.564662+0800 TestDemo[27076:497657] 快跑