Question

我最近开始使用Apple新语言Swift开发和Chromecast应用程序。但我一直坚持与Chromecast设备建立联系。到目前为止，它可以在网络上看到Chromecast。之后会出现一个AlertController（一个AlertController与ActionSheet相同）我之所以使用AlertController，是因为Apple不推荐使用ActionSheet。起初我认为将是ActionSheet使它无法正常工作。之后我尝试了不同版本的ActionController / ActionSheet，但到目前为止没有运气..作为在Swift中创建它的参考我在Objective C中使用了Google Cast示例应用程序。 https://github.com/googlecast/CastHelloText-ios

- 的更新 -

在Alertcontroller弹出窗口后，我点击它然后连接并成功的设备。当我尝试断开连接时，我会发现异常错误＆＃34; 在展开可选值时意外发现nil ＆＃34;。我在这行代码中收到此错误。

self.mediaInformation.metadata.stringForKey(kGCKMetadataKeyTitle)

所以基本上它说mediaInformation = nil，

self.mediaInformation.metadata.stringForKey(kGCKMetadataKeyTitle!)

所以我想让它让它可选，但那不起作用。有谁知道它为什么不起作用？

func chooseDevice() {
    if selectedDevice == nil {
        let alertController = UIAlertController(title: "Choose an device..", message: "Click on your chromecast!", preferredStyle: .ActionSheet)

        for device in deviceScanner.devices {
            alertController.addAction(UIAlertAction(title: device.friendlyName, style: .Default, handler: { alertAction in
                self.selectedDevice = device as GCKDevice
                self.connectToDevice()
            }))
        }

        let addCancelAction = UIAlertAction(title: "Cancel", style: .Cancel, handler: { alertAction in
            alertController.dismissViewControllerAnimated(true, completion: nil)
        })

        // Add action to the controller
        alertController.addAction(addCancelAction)

        // Finaly present the action controller
        presentViewController(alertController, animated: true, completion: nil)
    }
    else {
        updateButtonStates()

        var mediaTitle = GCKMediaInformation()
        mediaTitle.metadata.stringForKey(self.textFieldUrl.text)

        let alertController = UIAlertController(title: "Casting to: \(selectedDevice.friendlyName)", message: nil, preferredStyle: .ActionSheet)

        let addDisconnectingAction = UIAlertAction(title: "Disconnect device", style: .Destructive, handler: { alertAction in
            println("De waarde van mediaInformation is: \(self.mediaInformation)")
            if self.mediaInformation != nil {
                (self.mediaInformation != nil ? 1 : 0)
                alertController.dismissViewControllerAnimated(true, completion: nil)
                println("the else UIAlertController")
            }
        })

        let addCancelAction = UIAlertAction(title: "Cancel", style: .Cancel, handler: { alertAction in
            println("De waarde van mediaInformation is: \(self.mediaInformation)")
            if self.mediaInformation != nil {
                (self.mediaInformation != nil ? 2 : 1)
                alertController.dismissViewControllerAnimated(true, completion: nil)
                println("else uiactionsheet")
            }
        })

        alertController.addAction(addDisconnectingAction)
        alertController.addAction(addCancelAction)

        self.presentViewController(alertController, animated: true, completion: nil)
    }
}

这是我与Chromecast建立联系的方式。 connectToDevice()或deviceManagerDidConnect()可能有问题吗？很遗憾的是，我从来没有收到消息＆＃34; Connected＆＃34;在deviceManagerDidConnect()

func connectToDevice() {
    if selectedDevice != nil {
        var info = NSBundle.mainBundle().infoDictionary?["CFBundleVersion"] as? String
        deviceManager = GCKDeviceManager(device: selectedDevice, clientPackageName: info)

        NSLog("De waarde van info: \(info)")
        NSLog("De waarde van deviceManager in connectToDevice() is: \(deviceManager)")

        deviceManager = GCKDeviceManager(device: deviceScanner.devices[0] as GCKDevice, clientPackageName: info)
        deviceManager.delegate = self
        deviceManager.connect()
    }
}

    func deviceManagerDidConnect(deviceManager: GCKDeviceManager!) {
        NSLog("Connected!")

        updateButtonStates()

        deviceManager.launchApplication(kReceiverAppID)
}

Answer 1

我认为你需要在UIAlertAction的处理程序中做一些事情来设置self.selectedDevice

例如

    for selectedDevice in self.deviceScanner.devices {
        alertController.addAction(UIAlertAction(title: selectedDevice.friendlyName, style: .Default, handler: { action in
            self.selectedDevice = device
            self.connectToDevice()
        }))
    }

Answer 2

如果您没有播放任何媒体，媒体标题将为零，因此请以这种方式使用它：
声明：

var mediaInformation : GCKMediaInformation?

用法：的

let mediaTitle = self.mediaInformation?.metadata.stringForKey(kGCKMetadataKeyTitle)

使用Swift连接/断开Chromecast设备

2 个答案: