iOS-方法交换

@interface Person : NSObject

@end

@implementation Person

@end

@interface Person (swizzleExample)

@end

@implementation Person (swizzleExample)

- (void)swizzleExample {
    Class class = [self class];
    SEL originalSelector = @selector(originalMethod);
    SEL replacedSelector = @selector(replacedMethod);
    Method originalMethod = class_getInstanceMethod(class, originalSelector);
    Method replacedMethod = class_getInstanceMethod(class, replacedSelector);
    BOOL success = class_addMethod(class,
                                   originalSelector,
                                   method_getImplementation(replacedMethod),
                                   method_getTypeEncoding(replacedMethod));
    if (success) {
        class_replaceMethod(class,
                            replacedSelector,
                            method_getImplementation(originalMethod),
                            method_getTypeEncoding(originalMethod));
    } else {
        method_exchangeImplementations(originalMethod, replacedMethod);
    }
}

- (void)originalMethod {
    NSLog(@"方法名为 originalMethod，其 _cmd 的值为:%@",[NSString stringWithFormat:@"*** -%@", NSStringFromSelector(_cmd)]);
}


- (void)replacedMethod {
    NSLog(@"方法名为 replacedMethod，其 _cmd 的值为:%@",[NSString stringWithFormat:@"*** -%@", NSStringFromSelector(_cmd)]);
}

@end

Person *personModel = [[Person alloc] init];
  
    NSLog(@"## swizzle 之前，调用 originalMethod 的打印信息：");
    [personModel originalMethod];
    [personModel replacedMethod];
    
    [personModel swizzleExample];
    NSLog(@"## swizzle 之后，调用 originalMethod 的打印信息：");
    [personModel originalMethod];
    [personModel replacedMethod];

2022-03-03 10:34:36.975410+0800 dsadasdasdsa[14591:17348825] ## swizzle 之前，调用 originalMethod 的打印信息：
2022-03-03 10:34:36.975549+0800 dsadasdasdsa[14591:17348825] 方法名为 originalMethod，其 _cmd 的值为:*** -originalMethod
2022-03-03 10:34:36.975633+0800 dsadasdasdsa[14591:17348825] 方法名为 replacedMethod，其 _cmd 的值为:*** -replacedMethod
2022-03-03 10:34:36.975883+0800 dsadasdasdsa[14591:17348825] ## swizzle 之后，调用 originalMethod 的打印信息：
2022-03-03 10:34:36.975991+0800 dsadasdasdsa[14591:17348825] 方法名为 replacedMethod，其 _cmd 的值为:*** -originalMethod
2022-03-03 10:34:36.976091+0800 dsadasdasdsa[14591:17348825] 方法名为 originalMethod，其 _cmd 的值为:*** -replacedMethod