为了解决评论中提到的4G问题，我使用@AshleyMills的可达性实现作为参考，重写了Swift 3.1的可达性:
更新:Xcode 10.1•Swift 4或更高版本
Reachability.swift文件
import Foundation
import SystemConfiguration
class Reachability {
var hostname: String?
var isRunning = false
var isReachableOnWWAN: Bool
var reachability: SCNetworkReachability?
var reachabilityFlags = SCNetworkReachabilityFlags()
let reachabilitySerialQueue = DispatchQueue(label: "ReachabilityQueue")
init(hostname: String) throws {
guard let reachability = SCNetworkReachabilityCreateWithName(nil, hostname) else {
throw Network.Error.failedToCreateWith(hostname)
}
self.reachability = reachability
self.hostname = hostname
isReachableOnWWAN = true
try start()
}
init() throws {
var zeroAddress = sockaddr_in()
zeroAddress.sin_len = UInt8(MemoryLayout<sockaddr_in>.size)
zeroAddress.sin_family = sa_family_t(AF_INET)
guard let reachability = withUnsafePointer(to: &zeroAddress, {
$0.withMemoryRebound(to: sockaddr.self, capacity: 1) {
SCNetworkReachabilityCreateWithAddress(nil, $0)
}
}) else {
throw Network.Error.failedToInitializeWith(zeroAddress)
}
self.reachability = reachability
isReachableOnWWAN = true
try start()
}
var status: Network.Status {
return !isConnectedToNetwork ? .unreachable :
isReachableViaWiFi ? .wifi :
isRunningOnDevice ? .wwan : .unreachable
}
var isRunningOnDevice: Bool = {
#if targetEnvironment(simulator)
return false
#else
return true
#endif
}()
deinit { stop() }
}
extension Reachability {
func start() throws {
guard let reachability = reachability, !isRunning else { return }
var context = SCNetworkReachabilityContext(version: 0, info: nil, retain: nil, release: nil, copyDescription: nil)
context.info = Unmanaged<Reachability>.passUnretained(self).toOpaque()
guard SCNetworkReachabilitySetCallback(reachability, callout, &context) else { stop()
throw Network.Error.failedToSetCallout
}
guard SCNetworkReachabilitySetDispatchQueue(reachability, reachabilitySerialQueue) else { stop()
throw Network.Error.failedToSetDispatchQueue
}
reachabilitySerialQueue.async { self.flagsChanged() }
isRunning = true
}
func stop() {
defer { isRunning = false }
guard let reachability = reachability else { return }
SCNetworkReachabilitySetCallback(reachability, nil, nil)
SCNetworkReachabilitySetDispatchQueue(reachability, nil)
self.reachability = nil
}
var isConnectedToNetwork: Bool {
return isReachable &&
!isConnectionRequiredAndTransientConnection &&
!(isRunningOnDevice && isWWAN && !isReachableOnWWAN)
}
var isReachableViaWiFi: Bool {
return isReachable && isRunningOnDevice && !isWWAN
}
/// Flags that indicate the reachability of a network node name or address, including whether a connection is required, and whether some user intervention might be required when establishing a connection.
var flags: SCNetworkReachabilityFlags? {
guard let reachability = reachability else { return nil }
var flags = SCNetworkReachabilityFlags()
return withUnsafeMutablePointer(to: &flags) {
SCNetworkReachabilityGetFlags(reachability, UnsafeMutablePointer($0))
} ? flags : nil
}
/// compares the current flags with the previous flags and if changed posts a flagsChanged notification
func flagsChanged() {
guard let flags = flags, flags != reachabilityFlags else { return }
reachabilityFlags = flags
NotificationCenter.default.post(name: .flagsChanged, object: self)
}
/// The specified node name or address can be reached via a transient connection, such as PPP.
var transientConnection: Bool { return flags?.contains(.transientConnection) == true }
/// The specified node name or address can be reached using the current network configuration.
var isReachable: Bool { return flags?.contains(.reachable) == true }
/// The specified node name or address can be reached using the current network configuration, but a connection must first be established. If this flag is set, the kSCNetworkReachabilityFlagsConnectionOnTraffic flag, kSCNetworkReachabilityFlagsConnectionOnDemand flag, or kSCNetworkReachabilityFlagsIsWWAN flag is also typically set to indicate the type of connection required. If the user must manually make the connection, the kSCNetworkReachabilityFlagsInterventionRequired flag is also set.
var connectionRequired: Bool { return flags?.contains(.connectionRequired) == true }
/// The specified node name or address can be reached using the current network configuration, but a connection must first be established. Any traffic directed to the specified name or address will initiate the connection.
var connectionOnTraffic: Bool { return flags?.contains(.connectionOnTraffic) == true }
/// The specified node name or address can be reached using the current network configuration, but a connection must first be established.
var interventionRequired: Bool { return flags?.contains(.interventionRequired) == true }
/// The specified node name or address can be reached using the current network configuration, but a connection must first be established. The connection will be established "On Demand" by the CFSocketStream programming interface (see CFStream Socket Additions for information on this). Other functions will not establish the connection.
var connectionOnDemand: Bool { return flags?.contains(.connectionOnDemand) == true }
/// The specified node name or address is one that is associated with a network interface on the current system.
var isLocalAddress: Bool { return flags?.contains(.isLocalAddress) == true }
/// Network traffic to the specified node name or address will not go through a gateway, but is routed directly to one of the interfaces in the system.
var isDirect: Bool { return flags?.contains(.isDirect) == true }
/// The specified node name or address can be reached via a cellular connection, such as EDGE or GPRS.
var isWWAN: Bool { return flags?.contains(.isWWAN) == true }
/// The specified node name or address can be reached using the current network configuration, but a connection must first be established. If this flag is set
/// The specified node name or address can be reached via a transient connection, such as PPP.
var isConnectionRequiredAndTransientConnection: Bool {
return (flags?.intersection([.connectionRequired, .transientConnection]) == [.connectionRequired, .transientConnection]) == true
}
}
func callout(reachability: SCNetworkReachability, flags: SCNetworkReachabilityFlags, info: UnsafeMutableRawPointer?) {
guard let info = info else { return }
DispatchQueue.main.async {
Unmanaged<Reachability>
.fromOpaque(info)
.takeUnretainedValue()
.flagsChanged()
}
}
extension Notification.Name {
static let flagsChanged = Notification.Name("FlagsChanged")
}
struct Network {
static var reachability: Reachability!
enum Status: String {
case unreachable, wifi, wwan
}
enum Error: Swift.Error {
case failedToSetCallout
case failedToSetDispatchQueue
case failedToCreateWith(String)
case failedToInitializeWith(sockaddr_in)
}
}
使用
在你的AppDelegate.swift didFinishLaunchingWithOptions方法中初始化它，并处理任何可能发生的错误:
import UIKit
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
do {
try Network.reachability = Reachability(hostname: "www.google.com")
}
catch {
switch error as? Network.Error {
case let .failedToCreateWith(hostname)?:
print("Network error:\nFailed to create reachability object With host named:", hostname)
case let .failedToInitializeWith(address)?:
print("Network error:\nFailed to initialize reachability object With address:", address)
case .failedToSetCallout?:
print("Network error:\nFailed to set callout")
case .failedToSetDispatchQueue?:
print("Network error:\nFailed to set DispatchQueue")
case .none:
print(error)
}
}
return true
}
}
和一个视图控制器示例:
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default
.addObserver(self,
selector: #selector(statusManager),
name: .flagsChanged,
object: nil)
updateUserInterface()
}
func updateUserInterface() {
switch Network.reachability.status {
case .unreachable:
view.backgroundColor = .red
case .wwan:
view.backgroundColor = .yellow
case .wifi:
view.backgroundColor = .green
}
print("Reachability Summary")
print("Status:", Network.reachability.status)
print("HostName:", Network.reachability.hostname ?? "nil")
print("Reachable:", Network.reachability.isReachable)
print("Wifi:", Network.reachability.isReachableViaWiFi)
}
@objc func statusManager(_ notification: Notification) {
updateUserInterface()
}
}
示例项目