swift - 通过多个 View Controller 的多点连接

Question

我想要做的是拥有多个 View Controller ，其中一个将您与多点连接中的另一台设备连接起来。然后我希望用户能够切换 View Controller 并保持该连接。我对此进行了一些研究，发现我需要创建一个自定义类并在那里完成所有的多人工作。我找到了一个示例项目来展示这一点，但只有一个问题，如果代码不在 View Controller 中，我如何制作 MCBrowserViewController。

这是自定义类的代码:

import Foundation
import MultipeerConnectivity

protocol ColorServiceDelegate {

    func connectedDevicesChanged(manager : ColorService, connectedDevices: [String])
    func colorChanged(manager : ColorService, colorString: String)

}

class ColorService : NSObject {

    // Service type must be a unique string, at most 15 characters long
    // and can contain only ASCII lowercase letters, numbers and hyphens.
    private let ColorServiceType = "example-color"

    private let myPeerId = MCPeerID(displayName: UIDevice.current.name)
    private let serviceAdvertiser : MCNearbyServiceAdvertiser
    private let serviceBrowser : MCBrowserViewController

    var delegate : ColorServiceDelegate?

    lazy var session : MCSession = {
        let session = MCSession(peer: self.myPeerId, securityIdentity: nil, encryptionPreference: .required)
        session.delegate = self
        return session
    }()

    override init() {
        self.serviceAdvertiser = MCNearbyServiceAdvertiser(peer: myPeerId, discoveryInfo: nil, serviceType: ColorServiceType)
        self.serviceBrowser = MCBrowserViewController(peer: myPeerId, serviceType: ColorServiceType)

        super.init()

        self.serviceAdvertiser.delegate = self
        self.serviceAdvertiser.startAdvertisingPeer()


    }

    deinit {
        self.serviceAdvertiser.stopAdvertisingPeer()
        self.serviceBrowser.stopBrowsingForPeers()
    }

    func send(colorName : String) {
        NSLog("%@", "sendColor: \(colorName) to \(session.connectedPeers.count) peers")

        if session.connectedPeers.count > 0 {
            do {
                try self.session.send(colorName.data(using: .utf8)!, toPeers: session.connectedPeers, with: .reliable)
            }
            catch let error {
                NSLog("%@", "Error for sending: \(error)")
            }
        }

    }

}

extension ColorService : MCNearbyServiceAdvertiserDelegate {

    func advertiser(_ advertiser: MCNearbyServiceAdvertiser, didNotStartAdvertisingPeer error: Error) {
        NSLog("%@", "didNotStartAdvertisingPeer: \(error)")
    }

    func advertiser(_ advertiser: MCNearbyServiceAdvertiser, didReceiveInvitationFromPeer peerID: MCPeerID, withContext context: Data?, invitationHandler: @escaping (Bool, MCSession?) -> Void) {
        NSLog("%@", "didReceiveInvitationFromPeer \(peerID)")
        invitationHandler(true, self.session)
    }

}

extension ColorService : MCNearbyServiceBrowserDelegate {

    func browser(_ browser: MCNearbyServiceBrowser, didNotStartBrowsingForPeers error: Error) {
        NSLog("%@", "didNotStartBrowsingForPeers: \(error)")


    }
    // This is what pairs:
    func browser(_ browser: MCNearbyServiceBrowser, foundPeer peerID: MCPeerID, withDiscoveryInfo info: [String : String]?) {
        NSLog("%@", "foundPeer: \(peerID)")
        NSLog("%@", "invitePeer: \(peerID)")
        browser.invitePeer(peerID, to: self.session, withContext: nil, timeout: 10)
    }

    func browser(_ browser: MCNearbyServiceBrowser, lostPeer peerID: MCPeerID) {
        NSLog("%@", "lostPeer: \(peerID)")
    }

}

extension ColorService : MCSessionDelegate {

    func session(_ session: MCSession, peer peerID: MCPeerID, didChange state: MCSessionState) {
        switch state{
        case MCSessionState.connected:
            print("connected: \(peerID.displayName)")

        case MCSessionState.connecting:
            print("connecting: \(peerID.displayName)")
        case MCSessionState.notConnected:
            print("NotConnected: \(peerID.displayName)")

        }
    }

    func session(_ session: MCSession, didReceive data: Data, fromPeer peerID: MCPeerID) {
        let str = String(data: data, encoding: .utf8)!
        self.delegate?.colorChanged(manager: self, colorString: str)
    }

    func session(_ session: MCSession, didReceive stream: InputStream, withName streamName: String, fromPeer peerID: MCPeerID) {
        NSLog("%@", "didReceiveStream")
    }

    func session(_ session: MCSession, didStartReceivingResourceWithName resourceName: String, fromPeer peerID: MCPeerID, with progress: Progress) {
        NSLog("%@", "didStartReceivingResourceWithName")
    }

    func session(_ session: MCSession, didFinishReceivingResourceWithName resourceName: String, fromPeer peerID: MCPeerID, at localURL: URL?, withError error: Error?) {
        NSLog("%@", "didFinishReceivingResourceWithName")

    }

}

声明 MCBrowserViewController 时我习惯的是这样的:

let mcBrowser = MCBrowserViewController(serviceType: "doesnt-matter", session: self.mcSession)
mcBrowser.delegate = self
self.present(mcBrowser, animated: true, completion: nil)

但我不知道如何从 View Controller 外部执行此操作

Answer 1

您可以将 service 设置为 View Controller 类的属性。

这个服务类并不是设计为您共享的代码片段中的单例，这里有意义的是为您将呈现的每个 View Controller 实例化一个服务类。

要记住的一件重要的事情是:如果您要关闭 View Controller 并重新呈现它们，那么您将需要维护一个强引用(let)其他类(也许是您正在呈现的类？)，以便 View Controller 不会被初始化并终止您的 session 。

请告诉我这是否有帮助，否则如果您有更多信息，我可以编辑我的答案。