MCSessionState從連接狀態更改為未連接狀態

Question

每當我嘗試使用Multipeer Connectivity Framework連接對等方時，對等方的狀態將從MCSessionState.Connecting更改為MCSessionState.NotConnected 。

這是我運行的事件的順序：

1. 模擬器通過MCNearbyServiceAdvertiser通告服務。
2. iPhone通過MCNearbyServiceBrowser瀏覽服務。
3. iPhone找到了模擬器，並立即通過InvitationPeer（_：toSession：withContext：timeout :)邀請它加入會話。
4. 最后，模擬器使用Advertiser（_：didReceiveInvitationFromPeer：withContext：invitationHandler :)接受邀請 。

筆記：

• 即使我不需要安全性，我也接受客戶端發送的任何證書，以防出現bug 。

這是我正在使用的代碼：

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"
        }
    }
}

這里有一個類似的問題 ，但是，鏈接的代碼很舊，無法再訪問。 此外，問題在於正在使用同一會話對象。

Answer 1

我為MCSession，MCNearbyServiceAdvertiser和MCNearbyServiceBrowser使用了不同的MCPeerID實例。

為了解決這個問題，我創建了一個MCPeerID實例變量：

var localPeerID: MCPeerID?

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

...，而不是將其創建為局部變量（ let localPeerID = ... ）。

現在從連接到連接狀態正確地去。

Answer 2

始終可以將其創建為類的常量！

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

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