在 Swift 中使用 Chromecast 初始化

Question

我最近开始在 iOS 中使用 Google Cast API，我正在尝试让它与 Apple 新的编程语言 Swift 一起使用。 我在https://github.com/googlecast/CastHelloText-ios 用作参考Google 示例应用程序，问题是当我启动模拟器时，我收到一条错误消息，名为："-[GCKDeviceManager init]: unrecognized selector sent to instance 0x7fcd7a52d340" I知道我忘记了一些东西，但是我需要把它放在什么地方？？

为了更容易帮助我，这是我的代码。

class SettingsController: UIViewController, UITextFieldDelegate, GCKDeviceScannerListener, GCKDeviceManagerDelegate, GCKMediaControlChannelDelegate {

var deviceScanner : GCKDeviceScanner!
var deviceManager : GCKDeviceManager!
var mediaInformation : GCKMediaInformation!
var applicationMetadata : GCKApplicationMetadata!
var mediaControlChannel : GCKMediaControlChannelDelegate!
var selectedDevice : GCKDevice!
var textChannelVar : textChannel!
var chromecastButton : UIButton!
var btnImage : UIImage!
var btnImageSelected : UIImage!
var kReceiverAppID = "642B7ADB"

func chooseDevice() {
    if self.selectedDevice == nil {
        let alertController = UIAlertController(title: "Choose an device..", message: "Tap on a prefered device", preferredStyle: .ActionSheet)

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

        alertController.addAction(UIAlertAction(title: "Cancel", style: .Cancel, handler: { AlertAction in
            alertController.dismissViewControllerAnimated(true, completion: nil)
        }))

        self.presentViewController(alertController, animated: true, completion: { () -> Void in
            if self.selectedDevice != nil {
                self.connectToDevice()
            }
        })
    }
    else {
        self.updateButtonStates()

        self.mediaInformation.metadata.stringForKey(kGCKMetadataKeyTitle)

        var alertController =  UIAlertController(title: "Casting to: \(self.selectedDevice.friendlyName)", message: nil, preferredStyle: UIAlertControllerStyle.ActionSheet)
        alertController.addAction(UIAlertAction(title: "Disconnect", style: .Default, handler: { alertAction in
            println("de waarde van self.mediaInformation is : \(self.mediaInformation)")
            if self.mediaInformation != nil {
                println("else uiactionsheet")
                (self.mediaInformation != nil ? 1 : 0)
                alertController.dismissViewControllerAnimated(true, completion: nil)
            }
        }))
        alertController.addAction(UIAlertAction(title: "Cancel", style: .Cancel, handler: { alertAction in
            if self.mediaInformation != nil {
                println("else uiactionsheet")
                (self.mediaInformation != nil ? 2 : 1)
                alertController.dismissViewControllerAnimated(true, completion: nil)
            }
        }))
        self.presentViewController(alertController, animated: true, completion: nil)
    }
}

func isConnected() -> Bool {
    return self.deviceManager.isConnected
}

func connectToDevice() {
    if self.selectedDevice == nil {
        self.deviceManager = GCKDeviceManager(device: self.selectedDevice, clientPackageName:"CFBundleIdentifier")
        self.deviceManager.delegate = self
        self.deviceManager.connect()
        return
    }
}

func deviceDisconnected() {
    self.deviceManager = nil
    self.selectedDevice = nil
    self.textChannelVar = nil
    NSLog("Device disconneted: \(self.selectedDevice.friendlyName)")
}

func updateButtonStates() {
    if (self.deviceScanner.devices.count == 0) {
        chromecastButton.setImage(btnImage, forState: .Normal)
        chromecastButton.hidden = true
    }
    else {
        chromecastButton.setImage(btnImage, forState: .Normal)
        chromecastButton.hidden = false
        if (self.deviceManager != nil) {
            if self.deviceManager.isConnected {
                chromecastButton.setImage(btnImageSelected, forState: .Normal)
            }
        }
        else {
            chromecastButton.setImage(btnImageSelected, forState: .Normal)
        }
    }
}

func deviceDidComeOnline(device: GCKDevice!) {
    NSLog("device found! \(device.friendlyName)")
    self.updateButtonStates()
}

func deviceDidGoOffline(device: GCKDevice!) {
    self.updateButtonStates()
}

func actionSheet(actionSheet: UIActionSheet, clickedButtonAtIndex buttonIndex: Int) {
    if self.selectedDevice == nil {
        if buttonIndex < self.deviceScanner.devices.count {
            self.selectedDevice = self.deviceScanner.devices[buttonIndex] as GCKDevice
            NSLog("Selecting device: \(self.selectedDevice.friendlyName)")
            self.connectToDevice()
        }
    }
    else {
        if buttonIndex == 1 {
            NSLog("Disconnecting device: \(self.selectedDevice.friendlyName)")
            self.deviceManager.leaveApplication()
            self.deviceManager.disconnect()
            self.deviceDisconnected()
            self.updateButtonStates()
        }
        else if buttonIndex == 0 {
        }
    }
}

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

    self.updateButtonStates()

    self.deviceManager.launchApplication(kReceiverAppID)
}

func deviceManager(deviceManager: GCKDeviceManager!, didConnectToCastApplication applicationMetadata: GCKApplicationMetadata!, sessionID: String!, launchedApplication: Bool) {
    NSLog("application has launched \(launchedApplication)")

}

func deviceManager(deviceManager: GCKDeviceManager!, didFailToConnectToApplicationWithError error: NSError!) {
    self.showError(error)

    self.deviceDisconnected()
    self.updateButtonStates()
}

func deviceManager(deviceManager: GCKDeviceManager!, didFailToConnectWithError error: NSError!) {
    self.showError(error)

    self.deviceDisconnected()
    self.updateButtonStates()
}

func deviceManager(deviceManager: GCKDeviceManager!, didDisconnectWithError error: NSError!) {
    NSLog("Received notification that device disconnected")

    if error != nil {
        self.showError(error)
    }

    self.deviceDisconnected()
    self.updateButtonStates()
}

func showError(error: NSError) {
    var alert = UIAlertController(title: "Something went wrong", message: error.description, preferredStyle: UIAlertControllerStyle.Alert)
    alert.addAction(UIAlertAction(title: "Click", style: UIAlertActionStyle.Default, handler: nil))
    self.presentViewController(alert, animated: true, completion: nil)
}

override func viewDidLoad() {
    super.viewDidLoad()

    kReceiverAppID = kGCKMediaDefaultReceiverApplicationID

    btnImage = UIImage(named: "icon-cast-identified.png")
    btnImageSelected = UIImage(named: "icon-cast-connected")

    self.chromecastButton = UIButton.buttonWithType(UIButtonType.Custom) as UIButton
    self.chromecastButton.addTarget(self, action: "chooseDevice", forControlEvents: .TouchDown)
    self.chromecastButton.frame = CGRectMake(0, 0, 39, 34)
    self.chromecastButton.setImage(nil, forState: .Normal)
    self.chromecastButton.hidden = true


    self.deviceScanner = GCKDeviceScanner()
    self.deviceScanner.addListener(self)
    self.deviceScanner.startScan()

    self.view.addSubview(self.chromecastButton)
}

我的主要目标是在大屏幕上显示网页，我们通常在 webview 中看到的内容。 对不起，长代码。如果您需要更多信息来帮助我，请随时询问。 谢谢！

Answer 1

我没有使用过这个库，但是在您提供的链接中，他们正在像这样初始化 GCKDeviceManager：

self.deviceManager =
  [[GCKDeviceManager alloc] initWithDevice:self.selectedDevice
                         clientPackageName:[info objectForKey:@"CFBundleIdentifier"]];

这应该翻译成这个 swift 代码：

self.deviceManager = GCKDeviceManager(self.selectedDevice, clientPackageName:info["CFBundleIdentifier"])

这意味着您的代码看起来像这样是无效的（或者至少是 GCKDeviceManager 初始化）：

var deviceScanner = GCKDeviceScanner()
var deviceManager = GCKDeviceManager()
var mediaInformation = GCKMediaInformation()
var selectedDevice = GCKDevice()

您应该改为如下所示：

var deviceScanner : GCKDeviceScanner!
var deviceManager : GCKDeviceManager!
var mediaInformation : GCKMediaInformation!
var selectedDevice : GCKDevice!

在访问这些值之前，您需要确保已分配这些值，否则会崩溃。否则，您可以将类型切换为可选项。