如何使用RACCommand处理确认

Question

我刚开始在我的项目中使用ReactiveCocoa。我正在尝试弄清楚如何在使用UIAlertView时处理确认请求。

我似乎无法绕过这个。

1. 启用按钮并进行验证
2. 显示UIAlertView并检查选择了哪个按钮索引
3. 如果是，请继续从服务器获取数据，如果不执行任何操作。

如何在执行开始之前首先显示UIAlertView？

class MyViewModel: NSObject {
    dynamic var myText = ""

    var executeTransaction: RACCommand!

    override init() {
        super.init()

        let validSignal = RACObserve(self, "myText").mapAs {
            (text: NSString) -> NSNumber in
            return text.length >= 10
        }.distinctUntilChanged()

        self.executeTransaction = RACCommand(enabled: validSignal, signalBlock: {
        (any: AnyObject!) -> RACSignal! in
            return self.executingTransactionSignal()
        })
    }

    func executingTransactionSignal() -> RACSignal! {
        return RACSignal.createSignal {
            subscriber in
            subscriber.sendNext("testing")
            subscriber.sendCompleted()
            return nil
        }
    }
}


class MyViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        self.inputField.rac_textSignal() ~> RAC(self.viewModel, "myText")

        self.verifyButton.rac_command = self.viewModel.executeTransaction

        let alert = UIAlertView(title: "Title", message: "Continue", delegate: nil, cancelButtonTitle: "Change", otherButtonTitles: "Yes")

        let alertSignal = return alert.rac_buttonClickedSignal().map({ (buttonIndex) -> AnyObject! in
            let index = buttonIndex as Int
            return index == 1
        })

        // trying see how to show, and subscribe to self.viewModels.executeTransaction.executionSignals 
    }
}

---

...更新

我最终做的是在我的视图模型中创建一个接受闭包的方法，并返回RACCommand。我不确定如果这是最优雅的方式。