这是我自己发现的。
Xcode: 7.3.1, iOS 9.3.3
在我的项目中使用ashleymills/Reachability.swift作为Reachability.swift，我创建了以下函数:
func hasConnectivity() -> Bool {
do {
let reachability: Reachability = try Reachability.reachabilityForInternetConnection()
let networkStatus: Int = reachability.currentReachabilityStatus.hashValue
return (networkStatus != 0)
}
catch {
// Handle error however you please
return false
}
}
只要在需要检查连接的地方调用hasConnectivity()即可。这适用于Wifi和蜂窝网络。
添加ashleyymills的reacbility .swift，这样人们就不必在不同的网站之间切换了:
Copyright (c) 2014, Ashley Mills
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/
// Reachability.swift version 2.2beta2
import SystemConfiguration
import Foundation
public enum ReachabilityError: ErrorType {
case FailedToCreateWithAddress(sockaddr_in)
case FailedToCreateWithHostname(String)
case UnableToSetCallback
case UnableToSetDispatchQueue
}
public let ReachabilityChangedNotification = "ReachabilityChangedNotification"
func callback(reachability:SCNetworkReachability, flags: SCNetworkReachabilityFlags, info: UnsafeMutablePointer<Void>) {
let reachability = Unmanaged<Reachability>.fromOpaque(COpaquePointer(info)).takeUnretainedValue()
dispatch_async(dispatch_get_main_queue()) {
reachability.reachabilityChanged(flags)
}
}
public class Reachability: NSObject {
public typealias NetworkReachable = (Reachability) -> ()
public typealias NetworkUnreachable = (Reachability) -> ()
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"
}
}
}
// MARK: - *** Public properties ***
public var whenReachable: NetworkReachable?
public var whenUnreachable: NetworkUnreachable?
public var reachableOnWWAN: Bool
public var notificationCenter = NSNotificationCenter.defaultCenter()
public var currentReachabilityStatus: NetworkStatus {
if isReachable() {
if isReachableViaWiFi() {
return .ReachableViaWiFi
}
if isRunningOnDevice {
return .ReachableViaWWAN
}
}
return .NotReachable
}
public var currentReachabilityString: String {
return "\(currentReachabilityStatus)"
}
private var previousFlags: SCNetworkReachabilityFlags?
// MARK: - *** Initialisation methods ***
required public init(reachabilityRef: SCNetworkReachability) {
reachableOnWWAN = true
self.reachabilityRef = reachabilityRef
}
public convenience init(hostname: String) throws {
let nodename = (hostname as NSString).UTF8String
guard let ref = SCNetworkReachabilityCreateWithName(nil, nodename) else { throw ReachabilityError.FailedToCreateWithHostname(hostname) }
self.init(reachabilityRef: ref)
}
public class func reachabilityForInternetConnection() throws -> Reachability {
var zeroAddress = sockaddr_in()
zeroAddress.sin_len = UInt8(sizeofValue(zeroAddress))
zeroAddress.sin_family = sa_family_t(AF_INET)
guard let ref = withUnsafePointer(&zeroAddress, {
SCNetworkReachabilityCreateWithAddress(nil, UnsafePointer($0))
}) else { throw ReachabilityError.FailedToCreateWithAddress(zeroAddress) }
return Reachability(reachabilityRef: ref)
}
public class func reachabilityForLocalWiFi() throws -> Reachability {
var localWifiAddress: sockaddr_in = sockaddr_in(sin_len: __uint8_t(0), sin_family: sa_family_t(0), sin_port: in_port_t(0), sin_addr: in_addr(s_addr: 0), sin_zero: (0, 0, 0, 0, 0, 0, 0, 0))
localWifiAddress.sin_len = UInt8(sizeofValue(localWifiAddress))
localWifiAddress.sin_family = sa_family_t(AF_INET)
// IN_LINKLOCALNETNUM is defined in <netinet/in.h> as 169.254.0.0
let address: UInt32 = 0xA9FE0000
localWifiAddress.sin_addr.s_addr = in_addr_t(address.bigEndian)
guard let ref = withUnsafePointer(&localWifiAddress, {
SCNetworkReachabilityCreateWithAddress(nil, UnsafePointer($0))
}) else { throw ReachabilityError.FailedToCreateWithAddress(localWifiAddress) }
return Reachability(reachabilityRef: ref)
}
// MARK: - *** Notifier methods ***
public func startNotifier() throws {
guard !notifierRunning else { return }
var context = SCNetworkReachabilityContext(version: 0, info: nil, retain: nil, release: nil, copyDescription: nil)
context.info = UnsafeMutablePointer(Unmanaged.passUnretained(self).toOpaque())
if !SCNetworkReachabilitySetCallback(reachabilityRef!, callback, &context) {
stopNotifier()
throw ReachabilityError.UnableToSetCallback
}
if !SCNetworkReachabilitySetDispatchQueue(reachabilityRef!, reachabilitySerialQueue) {
stopNotifier()
throw ReachabilityError.UnableToSetDispatchQueue
}
// Perform an intial check
dispatch_async(reachabilitySerialQueue) { () -> Void in
let flags = self.reachabilityFlags
self.reachabilityChanged(flags)
}
notifierRunning = true
}
public func stopNotifier() {
defer { notifierRunning = false }
guard let reachabilityRef = reachabilityRef else { return }
SCNetworkReachabilitySetCallback(reachabilityRef, nil, nil)
SCNetworkReachabilitySetDispatchQueue(reachabilityRef, nil)
}
// MARK: - *** Connection test methods ***
public func isReachable() -> Bool {
let flags = reachabilityFlags
return isReachableWithFlags(flags)
}
public func isReachableViaWWAN() -> Bool {
let flags = reachabilityFlags
// Check we're not on the simulator, we're REACHABLE and check we're on WWAN
return isRunningOnDevice && isReachable(flags) && isOnWWAN(flags)
}
public func isReachableViaWiFi() -> Bool {
let flags = reachabilityFlags
// Check we're reachable
if !isReachable(flags) {
return false
}
// Must be on WiFi if reachable but not on an iOS device (i.e. simulator)
if !isRunningOnDevice {
return true
}
// Check we're NOT on WWAN
return !isOnWWAN(flags)
}
// MARK: - *** Private methods ***
private var isRunningOnDevice: Bool = {
#if (arch(i386) || arch(x86_64)) && os(iOS)
return false
#else
return true
#endif
}()
private var notifierRunning = false
private var reachabilityRef: SCNetworkReachability?
private let reachabilitySerialQueue = dispatch_queue_create("uk.co.ashleymills.reachability", DISPATCH_QUEUE_SERIAL)
private func reachabilityChanged(flags: SCNetworkReachabilityFlags) {
guard previousFlags != flags else { return }
if isReachableWithFlags(flags) {
if let block = whenReachable {
block(self)
}
} else {
if let block = whenUnreachable {
block(self)
}
}
notificationCenter.postNotificationName(ReachabilityChangedNotification, object:self)
previousFlags = flags
}
private func isReachableWithFlags(flags: SCNetworkReachabilityFlags) -> Bool {
if !isReachable(flags) {
return false
}
if isConnectionRequiredOrTransient(flags) {
return false
}
if isRunningOnDevice {
if isOnWWAN(flags) && !reachableOnWWAN {
// We don't want to connect when on 3G.
return false
}
}
return true
}
// WWAN may be available, but not active until a connection has been established.
// WiFi may require a connection for VPN on Demand.
private func isConnectionRequired() -> Bool {
return connectionRequired()
}
private func connectionRequired() -> Bool {
let flags = reachabilityFlags
return isConnectionRequired(flags)
}
// Dynamic, on demand connection?
private func isConnectionOnDemand() -> Bool {
let flags = reachabilityFlags
return isConnectionRequired(flags) && isConnectionOnTrafficOrDemand(flags)
}
// Is user intervention required?
private func isInterventionRequired() -> Bool {
let flags = reachabilityFlags
return isConnectionRequired(flags) && isInterventionRequired(flags)
}
private func isOnWWAN(flags: SCNetworkReachabilityFlags) -> Bool {
#if os(iOS)
return flags.contains(.IsWWAN)
#else
return false
#endif
}
private func isReachable(flags: SCNetworkReachabilityFlags) -> Bool {
return flags.contains(.Reachable)
}
private func isConnectionRequired(flags: SCNetworkReachabilityFlags) -> Bool {
return flags.contains(.ConnectionRequired)
}
private func isInterventionRequired(flags: SCNetworkReachabilityFlags) -> Bool {
return flags.contains(.InterventionRequired)
}
private func isConnectionOnTraffic(flags: SCNetworkReachabilityFlags) -> Bool {
return flags.contains(.ConnectionOnTraffic)
}
private func isConnectionOnDemand(flags: SCNetworkReachabilityFlags) -> Bool {
return flags.contains(.ConnectionOnDemand)
}
func isConnectionOnTrafficOrDemand(flags: SCNetworkReachabilityFlags) -> Bool {
return !flags.intersect([.ConnectionOnTraffic, .ConnectionOnDemand]).isEmpty
}
private func isTransientConnection(flags: SCNetworkReachabilityFlags) -> Bool {
return flags.contains(.TransientConnection)
}
private func isLocalAddress(flags: SCNetworkReachabilityFlags) -> Bool {
return flags.contains(.IsLocalAddress)
}
private func isDirect(flags: SCNetworkReachabilityFlags) -> Bool {
return flags.contains(.IsDirect)
}
private func isConnectionRequiredOrTransient(flags: SCNetworkReachabilityFlags) -> Bool {
let testcase:SCNetworkReachabilityFlags = [.ConnectionRequired, .TransientConnection]
return flags.intersect(testcase) == testcase
}
private var reachabilityFlags: SCNetworkReachabilityFlags {
guard let reachabilityRef = reachabilityRef else { return SCNetworkReachabilityFlags() }
var flags = SCNetworkReachabilityFlags()
let gotFlags = withUnsafeMutablePointer(&flags) {
SCNetworkReachabilityGetFlags(reachabilityRef, UnsafeMutablePointer($0))
}
if gotFlags {
return flags
} else {
return SCNetworkReachabilityFlags()
}
}
override public var description: String {
var W: String
if isRunningOnDevice {
W = isOnWWAN(reachabilityFlags) ? "W" : "-"
} else {
W = "X"
}
let R = isReachable(reachabilityFlags) ? "R" : "-"
let c = isConnectionRequired(reachabilityFlags) ? "c" : "-"
let t = isTransientConnection(reachabilityFlags) ? "t" : "-"
let i = isInterventionRequired(reachabilityFlags) ? "i" : "-"
let C = isConnectionOnTraffic(reachabilityFlags) ? "C" : "-"
let D = isConnectionOnDemand(reachabilityFlags) ? "D" : "-"
let l = isLocalAddress(reachabilityFlags) ? "l" : "-"
let d = isDirect(reachabilityFlags) ? "d" : "-"
return "\(W)\(R) \(c)\(t)\(i)\(C)\(D)\(l)\(d)"
}
deinit {
stopNotifier()
reachabilityRef = nil
whenReachable = nil
whenUnreachable = nil
}
}