iOS开发之ReactiveCocoa入门基础

由于最近看到现在的招聘简历一言不合就来一波熟悉ReactiveCocoa函数链式编程，为了紧跟时代，于是作为菜鸟的我也来研究一波rac, 何为ReactiveCocoa(以下简称rac)? rac 由GitHub开源的一个应用于iOS和OS X开发的新框架(由19个大牛编写而来)。rac具有函数式编程和响应式编程的特性, 作为ios程序员，为何要使用rac呢? 请看下图:

RAC.png

没看懂？or不想看？好吧，作为只会Ctr C +V的我来说，敲代码就是一把梭，我可以说学习rac就是为了装一波X么？会不会被那打死？？
言归正传，当pod下来rac的代码下来试一波，你就会发现，rac用着巨爽，主要是为ios程序员省掉了很多代码量，可以让代码更加优雅，比如在OC里面的的常见事件处理，在rac里面的代码量就很少了,请看下图：

rac->structure.png

rac->UI.png

从上图我们可以看到rac对UI控件、代理、等等做了支持，具体的不多说，看下面的代码：

//taget-Action
    [[self.touch rac_signalForControlEvents:UIControlEventTouchUpInside] subscribeNext:^(id x) {
        NSLog(@"x = %@",x);
        _alertView = [[UIAlertView alloc] initWithTitle:@"xxx" message:@"xxx" delegate:self cancelButtonTitle:@"cancel" otherButtonTitles:@"other", nil];
        [_alertView show];
        /*
         //对delegate的支持
         [[self rac_signalForSelector:@selector(alertView:clickedButtonAtIndex:) fromProtocol:@protocol(UIAlertViewDelegate)] subscribeNext:^(RACTuple *tupe) {
         NSLog(@"first = %@",tupe.first);
         NSLog(@"second = %@",tupe.second);
         }];
         */
        @weakify(self);
        [[_alertView rac_buttonClickedSignal] subscribeNext:^(id x) {
            @strongify(self);
            //rac里面是使用weakify和stringify来避免循环引用
            NSLog(@"x = %@",x);
            NSInteger index =  [x integerValue];
            NSLog(@"你点击的是第%zd个按钮",index);
            if (index == 1) {
                NextVC *next = [NextVC new];
                next.delegate = self;
                [self.navigationController pushViewController:next animated:YES];
                
                ///rac对代理支持，但是这里值得注意的是，rac的代理目前只能支持返回值是void的代理，带有返回值的代理是不支持的
                [[self rac_signalForSelector:@selector(nextVC:value:) fromProtocol:@protocol(NextVCDelegate)] subscribeNext:^(RACTuple  * tupe) {
                    NSLog(@"value = %@",tupe);
                }];
            }
        }];
        //dismiss
        [[_alertView rac_willDismissSignal] subscribeNext:^(id x) {
            NSLog(@"alertView will dismiss \n x = %@",x);
        }];
    }];
    //通知
    [[[NSNotificationCenter defaultCenter] rac_addObserverForName:UIApplicationDidEnterBackgroundNotification object:nil] subscribeNext:^(NSNotification *noti) {
        NSLog(@"notification = %@",noti.name);
    }];
    
    //KVO
    [RACObserve(self.touch, frame) subscribeNext:^(id x) {
//        NSLog(@"frame = %@",[x CGRectValue]);
    }];
    
    self.view.userInteractionEnabled = YES;
    //对tap的监听
    UITapGestureRecognizer *tap = [UITapGestureRecognizer new];
    [[tap rac_gestureSignal] subscribeNext:^(id x) {
        NSLog(@"tapview = %@",((UITapGestureRecognizer *)x).view);
    }];
    [self.view addGestureRecognizer:tap];
    
    //信号量
    RACSignal *signal = [RACSignal createSignal:^RACDisposable *(id subscriber) {
        //发送next信号
        [subscriber sendNext:@"Chan"];
        //发送完成
        [subscriber sendCompleted];
        //释放操作
        return [RACDisposable disposableWithBlock:^{
            
        }];
    }];
    
    //订阅
    [signal subscribeNext:^(id x) {
        NSLog(@"x = %@",x);
    }];
    //订阅错误
    [signal doError:^(NSError *error) {
        NSLog(@"subcribe error = %@",error.localizedDescription);
    }];
    //订阅完成
    [signal doCompleted:^{
        
    }];
    
    _pickerController = [UIImagePickerController new];
    _pickerController.delegate = self;
    _pickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    _pickerController.allowsEditing = NO;
}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    self.touch.frame = CGRectMake(100, 100, 120, 50);
    [self presentViewController:_pickerController animated:YES completion:nil];
    [[self rac_signalForSelector:@selector(imagePickerController:didFinishPickingMediaWithInfo:) fromProtocol:@protocol(UIImagePickerControllerDelegate)] subscribeNext:^(RACTuple *tupe) {
        // tupe里面存着delegate里面的参数
        NSLog(@"first = %@\n second = %@",tupe.first,tupe.second);
    }];
}