我想检查一下我是否可以在iOS上使用Cocoa Touch库或在macOS上使用Cocoa库连接互联网。
我想出了一个方法来做这个使用NSURL。我的方法似乎有点不可靠(因为即使谷歌也可能有一天宕机，依赖第三方似乎很糟糕)，虽然如果谷歌没有响应，我可以检查其他一些网站的响应，但这似乎是浪费和不必要的应用程序开销。
- (BOOL)connectedToInternet {
NSString *URLString = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.google.com"]];
return ( URLString != NULL ) ? YES : NO;
}
是我做得不好，(更不用说stringWithContentsOfURL已弃用在iOS 3.0和macOS 10.4)，如果是这样，有什么更好的方法来实现这一点?
当前回答
Swift 3 / Swift 4
您必须首先导入
import SystemConfiguration
您可以通过以下方法检查Internet连接。
func isConnectedToNetwork() -> Bool {
var zeroAddress = sockaddr_in()
zeroAddress.sin_len = UInt8(MemoryLayout.size(ofValue: zeroAddress))
zeroAddress.sin_family = sa_family_t(AF_INET)
let defaultRouteReachability = withUnsafePointer(to: &zeroAddress) {
$0.withMemoryRebound(to: sockaddr.self, capacity: 1) {zeroSockAddress in
SCNetworkReachabilityCreateWithAddress(nil, zeroSockAddress)
}
}
var flags = SCNetworkReachabilityFlags()
if !SCNetworkReachabilityGetFlags(defaultRouteReachability!, &flags) {
return false
}
let isReachable = (flags.rawValue & UInt32(kSCNetworkFlagsReachable)) != 0
let needsConnection = (flags.rawValue & UInt32(kSCNetworkFlagsConnectionRequired)) != 0
return (isReachable && !needsConnection)
}
其他回答
Swift 5及以后:
public class Reachability {
class func isConnectedToNetwork() -> Bool {
var zeroAddress = sockaddr_in()
zeroAddress.sin_len = UInt8(MemoryLayout<sockaddr_in>.size)
zeroAddress.sin_family = sa_family_t(AF_INET)
guard let defaultRouteReachability = withUnsafePointer(to: &zeroAddress, {
$0.withMemoryRebound(to: sockaddr.self, capacity: 1) {
SCNetworkReachabilityCreateWithAddress(nil, $0)
}
}) else {
return false
}
var flags: SCNetworkReachabilityFlags = []
if !SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags) {
return false
}
let isReachable = flags.contains(.reachable)
let needsConnection = flags.contains(.connectionRequired)
return (isReachable && !needsConnection)
}
像这样调用这个类:
if Reachability.isConnectedToNetwork() == true {
// Do something
} else {
// Do something
}
- (void)viewWillAppear:(BOOL)animated
{
NSString *URL = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.google.com"]];
return (URL != NULL ) ? YES : NO;
}
或者使用Reachability类。
使用iPhone SDK有两种方法来检查网络可用性:
1. 检查“谷歌”页面是否打开。
2. 可达性类
有关更多信息，请参考Reachability (Apple Developer)。
//
// Connectivity.swift
//
//
// Created by Kausik Jati on 17/07/20.
//
//
import Foundation
import Network
enum ConnectionState: String {
case notConnected = "Internet connection not avalable"
case connected = "Internet connection avalable"
case slowConnection = "Internet connection poor"
}
protocol ConnectivityDelegate: class {
func checkInternetConnection(_ state: ConnectionState, isLowDataMode: Bool)
}
class Connectivity: NSObject {
private let monitor = NWPathMonitor()
weak var delegate: ConnectivityDelegate? = nil
private let queue = DispatchQueue.global(qos: .background)
private var isLowDataMode = false
static let instance = Connectivity()
private override init() {
super.init()
monitor.start(queue: queue)
startMonitorNetwork()
}
private func startMonitorNetwork() {
monitor.pathUpdateHandler = { path in
if #available(iOS 13.0, *) {
self.isLowDataMode = path.isConstrained
} else {
// Fallback on earlier versions
self.isLowDataMode = false
}
if path.status == .requiresConnection {
print("requiresConnection")
self.delegate?.checkInternetConnection(.slowConnection, isLowDataMode: self.isLowDataMode)
} else if path.status == .satisfied {
print("satisfied")
self.delegate?.checkInternetConnection(.connected, isLowDataMode: self.isLowDataMode)
} else if path.status == .unsatisfied {
print("unsatisfied")
self.delegate?.checkInternetConnection(.notConnected, isLowDataMode: self.isLowDataMode)
}
}
}
func stopMonitorNetwork() {
monitor.cancel()
}
}
当使用iOS 12或macOS v10.14 (Mojave)或更新版本时，您可以使用NWPathMonitor而不是史前可达性类。作为奖励，你可以很容易地检测到当前的网络连接类型:
import Network // Put this on top of your class
let monitor = NWPathMonitor()
monitor.pathUpdateHandler = { path in
if path.status != .satisfied {
// Not connected
}
else if path.usesInterfaceType(.cellular) {
// Cellular 3/4/5g connection
}
else if path.usesInterfaceType(.wifi) {
// Wi-Fi connection
}
else if path.usesInterfaceType(.wiredEthernet) {
// Ethernet connection
}
}
monitor.start(queue: DispatchQueue.global(qos: .background))
更多信息请访问:https://developer.apple.com/documentation/network/nwpathmonitor
这里有一个漂亮的，使用ARC和gcd的现代化可达性:
可达性
