消息转发

1.动态方法解析

+(void)load {
    Method oldMethod = class_getInstanceMethod(self, @selector(reloadData));
    Method newMethod = class_getInstanceMethod(self, @selector(lj_reloadData));
    method_exchangeImplementations(oldMethod, newMethod);
}
+ (BOOL)resolveInstanceMethod:(SEL)sel {
    NSString *methodName = NSStringFromSelector(sel);
    if ([methodName isEqualToString:@"sendMessage:"]) {
        return class_addMethod(self, sel, (IMP)sendMsg, "v@:@");
    }
    return NO;
}

2.备用接收者

- (id)forwardingTargetForSelector:(SEL)aSelector {
    NSString *methodName = NSStringFromSelector(aSelector);
    if ([methodName isEqualToString:@"sendMessage:"]) {
        NSLog(@"备用接受者 ");
        return [Message1 new];
    }
    return [super forwardingTargetForSelector:aSelector];
}

3.完整消息转发

- (NSMethodSignature *)methodSignatureForSelector:(SEL)aSelector {
    NSString *methodName = NSStringFromSelector(aSelector);
    if ([methodName isEqualToString:@"sendMessage:"]) {
        return [NSMethodSignature signatureWithObjCTypes:"v@:@"];
    }
    return [super methodSignatureForSelector:aSelector];
}
- (void)forwardInvocation:(NSInvocation *)anInvocation {
    SEL sel = [anInvocation selector];
    Message1 *tempObj = [Message1 new];
    if ([tempObj respondsToSelector:sel]) {
        [anInvocation invokeWithTarget:tempObj];
    }else {
        [super forwardInvocation:anInvocation];
    }
    [super forwardInvocation:anInvocation];
}

4.报错

- (void)doesNotRecognizeSelector:(SEL)aSelector {
    NSLog(@"找不到方法");
}