MCSessionState 从连接状态变为未连接状态

Posted 2023-03-11

【中文标题】MCSessionState 从连接状态变为未连接状态

【英文标题】：MCSessionState changes from connecting to not connected state

【发布时间】：2015-11-30 21:10:10

【问题描述】：

每当我尝试使用Multipeer Connectivity Framework 连接对等点时，对等点的状态都会从MCSessionState.Connecting 更改为MCSessionState.NotConnected。

这是我运行的事件的顺序：

模拟器通过MCNearbyServiceAdvertiser 宣传该服务。 iPhone 通过MCNearbyServiceBrowser 浏览服务。 iPhone 找到模拟器并立即将其邀请到 会议通过invitePeer(_:toSession:withContext:timeout:)。 最后，模拟器接受邀请使用 advertiser(_:didReceiveInvitationFromPeer:withContext:invitationHandler:)。

注意事项：

即使我不需要安全性，我也接受客户 in case that is the bug 发送的任何证书。

这是我正在使用的代码：

import UIKit
import MultipeerConnectivity

class ViewController: UIViewController 
    var advertiser: MCNearbyServiceAdvertiser!
    var browser: MCNearbyServiceBrowser!
    var session: MCSession!

    override func viewDidLoad() 
        super.viewDidLoad()
        let localPeerID = MCPeerID(displayName: UIDevice.currentDevice().name)
        session = MCSession(peer: localPeerID, securityIdentity: nil, encryptionPreference: MCEncryptionPreference.None)
        session.delegate = self
    

    @IBAction func hostTapped(sender: AnyObject) 
        let localPeerID = MCPeerID(displayName: UIDevice.currentDevice().name)
        advertiser = MCNearbyServiceAdvertiser(peer: localPeerID, discoveryInfo: nil, serviceType: "abc")
        advertiser.delegate = self
        print("started advertising")
        advertiser.startAdvertisingPeer()
    

    @IBAction func connectTapped(sender: AnyObject) 
        let localPeerID = MCPeerID(displayName: UIDevice.currentDevice().name)
        browser = MCNearbyServiceBrowser(peer: localPeerID, serviceType: "abc")
        browser.delegate = self
        print("started searching")
        browser.startBrowsingForPeers()
    


extension ViewController: MCNearbyServiceAdvertiserDelegate 
    func advertiser(advertiser: MCNearbyServiceAdvertiser, didReceiveInvitationFromPeer peerID: MCPeerID, withContext context: NSData?, invitationHandler: (Bool, MCSession) -> Void) 
        print("accepting invitation from \(peerID.displayName)")
        invitationHandler(true, session)
    

    func advertiser(advertiser: MCNearbyServiceAdvertiser, didNotStartAdvertisingPeer error: NSError) 
        print("did not start advertising \(error)")
    


extension ViewController: MCSessionDelegate 
    func session(session: MCSession, peer peerID: MCPeerID, didChangeState state: MCSessionState) 
        print("\(peerID.displayName) changed state: \(state.toString())")
    

    func session(session: MCSession, didReceiveData data: NSData, fromPeer peerID: MCPeerID) 

    

    func session(session: MCSession, didReceiveStream stream: NSInputStream, withName streamName: String, fromPeer peerID: MCPeerID) 

    

    func session(session: MCSession, didStartReceivingResourceWithName resourceName: String, fromPeer peerID: MCPeerID, withProgress progress: NSProgress) 

    

    func session(session: MCSession, didFinishReceivingResourceWithName resourceName: String, fromPeer peerID: MCPeerID, atURL localURL: NSURL, withError error: NSError?) 

    

    func session(session: MCSession, didReceiveCertificate certificate: [AnyObject]?, fromPeer peerID: MCPeerID, certificateHandler: (Bool) -> Void) 
        certificateHandler(true)
    


extension ViewController: MCNearbyServiceBrowserDelegate 
    func browser(browser: MCNearbyServiceBrowser, foundPeer peerID: MCPeerID, withDiscoveryInfo info: [String : String]?) 
        print("found \(peerID.displayName), inviting to session")
        browser.invitePeer(peerID, toSession: session, withContext: nil, timeout: 30)
    

    func browser(browser: MCNearbyServiceBrowser, lostPeer peerID: MCPeerID) 
        print("lost \(peerID.displayName)")
    


extension MCSessionState 
    func toString() -> String 
        switch self 
        case .Connected:    return "Connected"
        case .Connecting:   return "Connecting"
        case .NotConnected: return "Not Connected"
        
    

有一个类似的question here，但是，链接的代码是旧的，无法再访问。此外，问题在于使用了相同的会话对象。

【参考方案1】：

总是可以将它创建为类的常量！

class ViewController: UIViewController 
    var advertiser: MCNearbyServiceAdvertiser!
    var browser: MCNearbyServiceBrowser!
    var session: MCSession!

    let localPeerID = MCPeerID(displayName: UIDevice.currentDevice().name)
    ...

【参考方案2】：

我为 MCSession、MCNearbyServiceAdvertiser 和 MCNearbyServiceBrowser 使用了不同的 MCPeerID 实例。

为了解决这个问题，我创建了一个 MCPeerID 实例变量：

var localPeerID: MCPeerID?

override func viewDidLoad() 
    // ...
    localPeerID = MCPeerID(displayName: UIDevice.currentDevice().name)
    // ...

... 并使用它而不是将它们创建为局部变量 (let localPeerID = ...)。

它现在从 connecting 到 connected 状态正确。

【讨论】：

我遇到了同样的问题。感谢分享。

个人不喜欢在生产代码中强制展开，除非它真的无能为力。通过将其设置为常量并在声明点或延迟加载时进行初始化，这可以大大提高安全性:)