使用RACChannel進(jìn)行雙向數(shù)據(jù)綁定

RACChannel 非常適合于視圖和模型之間的雙向綁定，在對方的屬性或者狀態(tài)更新時(shí)及時(shí)通知自己，達(dá)到預(yù)期的效果；我們可以使用 ReactiveCocoa 中內(nèi)置的很多與 RACChannel 有關(guān)的方法，來獲取開箱即用的 RACChannelTerminal ，當(dāng)然也可以使用 RACChannelTo 通過 RACKVOChannel 來快速綁定類與類的屬性。

RACChannelTo(self.viewModel, username) = self.usernameTextField.rac_newTextChannel;

定時(shí)器，可以代替Timer

//這里要加takeUntil條件限制一下否則當(dāng)控制器pop后依舊會(huì)執(zhí)行
[[[RACSignal interval:2 onScheduler:[RACScheduler mainThreadScheduler]] takeUntil:self.rac_willDeallocSignal ] subscribeNext:^(id x) {
    
    NSLog(@"每兩秒執(zhí)行一次");
    
}];

RAC通知寫法

//代替通知
//takeUntil會(huì)接收一個(gè)signal,當(dāng)signal觸發(fā)后會(huì)把之前的信號(hào)釋放掉
[[[[NSNotificationCenter defaultCenter] rac_addObserverForName:UIKeyboardDidShowNotification object:nil] takeUntil:self.rac_willDeallocSignal] subscribeNext:^(id x) {
    
    NSLog(@"鍵盤彈出");
    
}];

多個(gè)請求，統(tǒng)一處理結(jié)果

- (void)testRACSignal
{
    // 創(chuàng)建信號(hào)A
    RACSignal *signalA = [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
        // 處理信號(hào)
        NSLog(@"%s 創(chuàng)建信號(hào)A", __FUNCTION__);
        // 發(fā)送數(shù)據(jù)
        [subscriber sendNext:@"熱門商品"];
        return nil;
    }];
    // 創(chuàng)建信號(hào)B
    RACSignal *signalB = [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
        // 處理信號(hào)
        NSLog(@"%s 創(chuàng)建信號(hào)", __FUNCTION__);
        // 發(fā)送數(shù)據(jù)
        [subscriber sendNext:@"最新商品"];
        
        return nil;
    }];
    
    // RAC:就可以判斷兩個(gè)信號(hào)有沒有都發(fā)出內(nèi)容
    // SignalsFromArray:監(jiān)聽哪些信號(hào)的發(fā)出
    // 當(dāng)signals數(shù)組中的所有信號(hào)都發(fā)送sendNext就會(huì)觸發(fā)方法調(diào)用者(self)的selector
    // 注意:selector方法的參數(shù)不能亂寫,有幾個(gè)信號(hào)就對應(yīng)幾個(gè)參數(shù)
    // 不需要主動(dòng)訂閱signalA,signalB,方法內(nèi)部會(huì)自動(dòng)訂閱
    [self rac_liftSelector:@selector(updateUIWithHot: new:) withSignalsFromArray:@[signalA,signalB]];
}
- (void)updateUIWithHot:(NSString *)hot new:(NSString *)new
{
    NSLog(@"%s hot = %@ , new = %@", __FUNCTION__, hot ,new);
}

重試

-(void)retry{
    __block int flag = 0;
    
    RACSignal *signal =  [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        
        if (flag == 4){
            [subscriber sendNext:@"1"];
            [subscriber sendCompleted];
        }else{
            flag ++;
            NSLog(@"flag= %d",flag);
            [subscriber sendError:[NSError errorWithDomain:@"myerror " code:100 userInfo:nil]];
        }
        return nil;
    }];
    [[signal retry:5]subscribeNext:^(id x) {
        NSLog(@"xxxx =%@",x);
    }];
    
}

發(fā)送請求，捕獲錯(cuò)誤處理

例子：如果在請求返回token過期，需要重新獲取token再繼續(xù)重新請求

// 發(fā)送請求
RACSignal *requestSignal = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
    NSString *url = @"http://httpbin.org/ip";
    [[AFHTTPRequestOperationManager manager] GET:url parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
        [subscriber sendNext:responseObject];
        [subscriber sendCompleted];
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        // token 過期
        [subscriber sendError:error];
    }];
    return nil;
}];

[[requestSignal catch:^RACSignal *(NSError *error) {
    // error捕獲
    return [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        // 模擬獲取token請求
        double delayInSeconds = 1.0;
        dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
        dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
            [subscriber sendNext:@YES];
            NSLog(@"subscriber sendNext...");
            [subscriber sendCompleted];
        });
        return nil;
    }] concat:requestSignal];   //RACSignal拼接，獲取token之后再重新請求
}] subscribeNext:^(id x) {
    // 請求正常返回的數(shù)據(jù)
    NSLog(@"next =%@",x);
} completed:^{
    NSLog(@"completed");

}];

搜索請求

使用節(jié)流器throttle，在0.3秒內(nèi)使用最后一個(gè)輸入text進(jìn)行請求

[[[[[[self.textField.rac_textSignal throttle:0.3] distinctUntilChanged] ignore:@""] map:^id(id value) {
    NSLog(@"value =%@",value);
    return [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        
        //  network request
        [subscriber sendNext:value];
        [subscriber sendCompleted];
        
        return [RACDisposable disposableWithBlock:^{
            
            //  cancel request
        }];
    }];
}] switchToLatest] subscribeNext:^(id x) {// 如果不switchToLastest 則返回一個(gè)signal
    
    NSLog(@"x = %@",x);
}];