• The problem

    Continue with the above [iOS to achieve WIFI book transfer], what if the LAN is removed? Whether files can be transferred between devices

    Common data transfer modes between iOS devices:

    Bluetooth 2. Airdrop 3.MultipeerConnectivityCopy the code

    This article is about MultipeerConnectivity

  • serving

    The device serves as the server

    • Have a PeerID that identifies you
    lazy var me: MCPeerID = {
    let peer = MCPeerID(displayName: UIDevice.current.name)
    return peer
}()
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    • A session
    lazy var session: MCSession = {
    let ss = MCSession(peer: me, securityIdentity: nil, encryptionPreference: .none)
    ss.delegate = self
    return ss
}()
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    • Broadcast it so other devices can find it
    lazy var advertiser: MCNearbyServiceAdvertiser = {
    let advertiser = MCNearbyServiceAdvertiser(peer: me, discoveryInfo: ["demo": "data"], serviceType: "shanzhai")
    advertiser.delegate = self
    return advertiser
}()
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    • Began to broadcast
    advertiser.startAdvertisingPeer()
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    • Broadcast proxy method execution
    extension MultipeerConnectVC: MCNearbyServiceAdvertiserDelegate { func advertiser(_ advertiser: MCNearbyServiceAdvertiser, didReceiveInvitationFromPeer peerID: MCPeerID, withContext context: Data? , invitationHandler: @escaping (Bool, MCSession?) -> Void) {// Confirm connection, assign session invitationHandler(true, session)} func advertiser(_ advertiser: MCNearbyServiceAdvertiser, didNotStartAdvertisingPeer error: Error) { advertiser.stopAdvertisingPeer() print("Woops! Advertising failed with error \(String(describing: error))") } }Copy the code

    The device serves as the client

    • Have a PeerID that identifies you
    lazy var me: MCPeerID = {
    let peer = MCPeerID(displayName: UIDevice.current.name)
    return peer
}()
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    • A session
    lazy var session: MCSession = {
    let ss = MCSession(peer: me, securityIdentity: nil, encryptionPreference: .none)
    ss.delegate = self
    return ss
}()
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    • A search is required for PeerID
    lazy var browser: MCNearbyServiceBrowser = {
    let bs = MCNearbyServiceBrowser(peer: me, serviceType: "shanzhai")
    bs.delegate = self
    return bs
}()
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    • Begin your search
    browser.startBrowsingForPeers()
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    • The nearby PeerID was retrieved from the proxy, which can be saved by itself or directly linked according to business requirements
    extension MultipeerConnectVC: MCNearbyServiceBrowserDelegate { func browser(_ browser: MCNearbyServiceBrowser, foundPeer peerID: MCPeerID, withDiscoveryInfo info: [String : String]?) {print("search peerId = \(peerId)") {print("search peerId = \(peerId)") {print("search peerId = \(peerId)"); session, withContext: nil, timeout: 10) } func browser(_ browser: MCNearbyServiceBrowser, lostPeer peerID: MCPeerID) { print("lost peerID = \(peerID)") } func browser(_ browser: MCNearbyServiceBrowser, didNotStartBrowsingForPeers error: Error) { print("error = \(error)") } }Copy the code

    The connection process looks at the Session, and the Session agent looks at each process

    extension MultipeerConnectVC: MCSessionDelegate { func session(_ session: MCSession, peer peerID: MCPeerID, didChange state: MCSessionState) { } func session(_ session: MCSession, didReceive data: Data, fromPeer peerID: MCPeerID) { } func session(_ session: MCSession, didReceive stream: InputStream, withName streamName: String, fromPeer peerID: MCPeerID) { } func session(_ session: MCSession, didStartReceivingResourceWithName resourceName: String, fromPeer peerID: MCPeerID, with progress: Progress) { } func session(_ session: MCSession, didFinishReceivingResourceWithName resourceName: String, fromPeer peerID: MCPeerID, at localURL: URL? , withError error: Error?) {}}Copy the code

    • Agent method didChange. MCSessionState ==. Connected in didChange

    • DidFinishReceivingResourceWithName agent method, you can view the received data

    • You can also use MCBrowserViewController, the PeerID that you find, you don’t have to write your own interface

  • conclusion

    This mode does not connect iOS and Android, and is applicable to non-network data transfer between Apple devices. The way FileChat is implemented across Apple devices should be based on this