当 wifi 重新打开时，Ashley Mills 可达性不发送通知？

Posted 2023-02-24

【中文标题】当 wifi 重新打开时，Ashley Mills 可达性不发送通知？

【英文标题】：Ashley Mills reachability not sending notification when wifi turns back on?

【发布时间】：2017-11-02 03:54:56

【问题描述】：

我有一个设置，使用Ashley Mills Reachability，它应该在应用程序的连接发生变化时使用NotificationCenter 向应用程序发送通知。设置如下：

func reachabilityChanged(note: Notification) 

        let reachability = note.object as! Reachability

        switch reachability.connection 
        case .wifi:
            print("Reachable via WiFi")
        case .cellular:
            print("Reachable via Cellular")
        case .none:
            print("Network not reachable")
        
    

override func viewDidLoad() 
        super.viewDidLoad()


        NotificationCenter.default.addObserver(self, selector: #selector(self.reachabilityChanged), name: .reachabilityChanged, object: reachability)
        do
            try reachability.startNotifier()
        catch
            print("could not start reachability notifier")
        
    

将我的计算机（我正在运行模拟器的计算机）连接到 wifi 后，控制台会准确打印“可通过 Wifi 访问”。关闭 wifi 会导致控制台再次准确打印“无法访问网络”。但是，当我重新打开 wifi 时，我遇到了问题。 “可通过 Wifi 访问”不会打印到日志中……事实上，日志中没有任何内容。我不知道为什么会发生这种情况，也不知道如何解决。有人有什么想法吗？ 这是可达性代码：

import SystemConfiguration
import Foundation

public enum ReachabilityError: Error 
    case FailedToCreateWithAddress(sockaddr_in)
    case FailedToCreateWithHostname(String)
    case UnableToSetCallback
    case UnableToSetDispatchQueue


@available(*, unavailable, renamed: "Notification.Name.reachabilityChanged")
public let ReachabilityChangedNotification = NSNotification.Name("ReachabilityChangedNotification")

extension Notification.Name 
    public static let reachabilityChanged = Notification.Name("reachabilityChanged")


func callback(reachability:SCNetworkReachability, flags: SCNetworkReachabilityFlags, info: UnsafeMutableRawPointer?) 

    guard let info = info else  return 

    let reachability = Unmanaged<Reachability>.fromOpaque(info).takeUnretainedValue()
    reachability.reachabilityChanged()


public class Reachability 

    public typealias NetworkReachable = (Reachability) -> ()
    public typealias NetworkUnreachable = (Reachability) -> ()

    @available(*, unavailable, renamed: "Conection")
    public enum NetworkStatus: CustomStringConvertible 
        case notReachable, reachableViaWiFi, reachableViaWWAN
        public var description: String 
            switch self 
            case .reachableViaWWAN: return "Cellular"
            case .reachableViaWiFi: return "WiFi"
            case .notReachable: return "No Connection"
            
        
    

    public enum Connection: CustomStringConvertible 
        case none, wifi, cellular
        public var description: String 
            switch self 
            case .cellular: return "Cellular"
            case .wifi: return "WiFi"
            case .none: return "No Connection"
            
        
    

    public var whenReachable: NetworkReachable?
    public var whenUnreachable: NetworkUnreachable?

    @available(*, deprecated: 4.0, renamed: "allowsCellularConnection")
    public let reachableOnWWAN: Bool = true

    /// Set to `false` to force Reachability.connection to .none when on cellular connection (default value `true`)
    public var allowsCellularConnection: Bool

    // The notification center on which "reachability changed" events are being posted
    public var notificationCenter: NotificationCenter = NotificationCenter.default

    @available(*, deprecated: 4.0, renamed: "connection.description")
    public var currentReachabilityString: String 
        return "\(connection)"
    

    @available(*, unavailable, renamed: "connection")
    public var currentReachabilityStatus: Connection 
        return connection
    

    public var connection: Connection 

        guard isReachableFlagSet else  return .none 

        // If we're reachable, but not on an ios device (i.e. simulator), we must be on WiFi
        guard isRunningOnDevice else  return .wifi 

        var connection = Connection.none

        if !isConnectionRequiredFlagSet 
            connection = .wifi
        

        if isConnectionOnTrafficOrDemandFlagSet 
            if !isInterventionRequiredFlagSet 
                connection = .wifi
            
        

        if isOnWWANFlagSet 
            if !allowsCellularConnection 
                connection = .none
             else 
                connection = .cellular
            
        

        return connection
    

    fileprivate var previousFlags: SCNetworkReachabilityFlags?

    fileprivate var isRunningOnDevice: Bool = 
        #if (arch(i386) || arch(x86_64)) && os(iOS)
            return false
        #else
            return true
        #endif
    ()

    fileprivate var notifierRunning = false
    fileprivate let reachabilityRef: SCNetworkReachability

    fileprivate let reachabilitySerialQueue = DispatchQueue(label: "uk.co.ashleymills.reachability")

    required public init(reachabilityRef: SCNetworkReachability) 
        allowsCellularConnection = true
        self.reachabilityRef = reachabilityRef
    

    public convenience init?(hostname: String) 

        guard let ref = SCNetworkReachabilityCreateWithName(nil, hostname) else  return nil 

        self.init(reachabilityRef: ref)
    

    public convenience init?() 

        var zeroAddress = sockaddr()
        zeroAddress.sa_len = UInt8(MemoryLayout<sockaddr>.size)
        zeroAddress.sa_family = sa_family_t(AF_INET)

        guard let ref = SCNetworkReachabilityCreateWithAddress(nil, &zeroAddress) else  return nil 

        self.init(reachabilityRef: ref)
    

    deinit 
        stopNotifier()
    


public extension Reachability 

    // MARK: - *** Notifier methods ***
    func startNotifier() throws 

        guard !notifierRunning else  return 

        var context = SCNetworkReachabilityContext(version: 0, info: nil, retain: nil, release: nil, copyDescription: nil)
        context.info = UnsafeMutableRawPointer(Unmanaged<Reachability>.passUnretained(self).toOpaque())        
        if !SCNetworkReachabilitySetCallback(reachabilityRef, callback, &context) 
            stopNotifier()
            throw ReachabilityError.UnableToSetCallback
        

        if !SCNetworkReachabilitySetDispatchQueue(reachabilityRef, reachabilitySerialQueue) 
            stopNotifier()
            throw ReachabilityError.UnableToSetDispatchQueue
        

        // Perform an initial check
        reachabilitySerialQueue.async 
            self.reachabilityChanged()
        

        notifierRunning = true
    

    func stopNotifier() 
        defer  notifierRunning = false 

        SCNetworkReachabilitySetCallback(reachabilityRef, nil, nil)
        SCNetworkReachabilitySetDispatchQueue(reachabilityRef, nil)
    

    // MARK: - *** Connection test methods ***
    @available(*, deprecated: 4.0, message: "Please use `connection != .none`")
    var isReachable: Bool 

        guard isReachableFlagSet else  return false 

        if isConnectionRequiredAndTransientFlagSet 
            return false
        

        if isRunningOnDevice 
            if isOnWWANFlagSet && !reachableOnWWAN 
                // We don't want to connect when on cellular connection
                return false
            
        

        return true
    

    @available(*, deprecated: 4.0, message: "Please use `connection == .cellular`")
    var isReachableViaWWAN: Bool 
        // Check we're not on the simulator, we're REACHABLE and check we're on WWAN
        return isRunningOnDevice && isReachableFlagSet && isOnWWANFlagSet
    

    @available(*, deprecated: 4.0, message: "Please use `connection == .wifi`")
    var isReachableViaWiFi: Bool 

        // Check we're reachable
        guard isReachableFlagSet else  return false 

        // If reachable we're reachable, but not on an iOS device (i.e. simulator), we must be on WiFi
        guard isRunningOnDevice else  return true 

        // Check we're NOT on WWAN
        return !isOnWWANFlagSet
    

    var description: String 

        let W = isRunningOnDevice ? (isOnWWANFlagSet ? "W" : "-") : "X"
        let R = isReachableFlagSet ? "R" : "-"
        let c = isConnectionRequiredFlagSet ? "c" : "-"
        let t = isTransientConnectionFlagSet ? "t" : "-"
        let i = isInterventionRequiredFlagSet ? "i" : "-"
        let C = isConnectionOnTrafficFlagSet ? "C" : "-"
        let D = isConnectionOnDemandFlagSet ? "D" : "-"
        let l = isLocalAddressFlagSet ? "l" : "-"
        let d = isDirectFlagSet ? "d" : "-"

        return "\(W)\(R) \(c)\(t)\(i)\(C)\(D)\(l)\(d)"
    


fileprivate extension Reachability 

    func reachabilityChanged() 
        guard previousFlags != flags else  return 

        let block = connection != .none ? whenReachable : whenUnreachable

        DispatchQueue.main.async 
            block?(self)
            self.notificationCenter.post(name: .reachabilityChanged, object:self)
        

        previousFlags = flags
    

    var isOnWWANFlagSet: Bool 
        #if os(iOS)
            return flags.contains(.isWWAN)
        #else
            return false
        #endif
    
    var isReachableFlagSet: Bool 
        return flags.contains(.reachable)
    
    var isConnectionRequiredFlagSet: Bool 
        return flags.contains(.connectionRequired)
    
    var isInterventionRequiredFlagSet: Bool 
        return flags.contains(.interventionRequired)
    
    var isConnectionOnTrafficFlagSet: Bool 
        return flags.contains(.connectionOnTraffic)
    
    var isConnectionOnDemandFlagSet: Bool 
        return flags.contains(.connectionOnDemand)
    
    var isConnectionOnTrafficOrDemandFlagSet: Bool 
        return !flags.intersection([.connectionOnTraffic, .connectionOnDemand]).isEmpty
    
    var isTransientConnectionFlagSet: Bool 
        return flags.contains(.transientConnection)
    
    var isLocalAddressFlagSet: Bool 
        return flags.contains(.isLocalAddress)
    
    var isDirectFlagSet: Bool 
        return flags.contains(.isDirect)
    
    var isConnectionRequiredAndTransientFlagSet: Bool 
        return flags.intersection([.connectionRequired, .transientConnection]) == [.connectionRequired, .transientConnection]
    

    var flags: SCNetworkReachabilityFlags 
        var flags = SCNetworkReachabilityFlags()
        if SCNetworkReachabilityGetFlags(reachabilityRef, &flags) 
            return flags
         else 
            return SCNetworkReachabilityFlags()
        
    

【参考方案1】：

在模拟器中每次运行只会触发一次，但在真实的iOS设备上，它可以正常工作。