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

下载Reachability文件,https://gist.github.com/darkseed/1182373 在framework中添加CFNetwork.framework和'SystemConfiguration.framework' 导入“Reachability.h”

首先:在framework中添加CFNetwork.framework

代码:ViewController.m

- (void)viewWillAppear:(BOOL)animated
{
    Reachability *r = [Reachability reachabilityWithHostName:@"www.google.com"];
    NetworkStatus internetStatus = [r currentReachabilityStatus];

    if ((internetStatus != ReachableViaWiFi) && (internetStatus != ReachableViaWWAN))
    {
        /// Create an alert if connection doesn't work
        UIAlertView *myAlert = [[UIAlertView alloc]initWithTitle:@"No Internet Connection"   message:NSLocalizedString(@"InternetMessage", nil)delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];
        [myAlert show];
        [myAlert release];
    }
    else
    {
         NSLog(@"INTERNET IS CONNECT");
    }
}

其他回答

试试这个:

- (void) connection:(NSURLConnection *)connection didFailWithError:(NSError *)error


if ([self.delegate respondsToSelector:@selector(getErrorResponse:)]) {
    [self.delegate performSelector:@selector(getErrorResponse:) withObject:@"No Network Connection"];
}

UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"BMC" message:@"No Network Connection" delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK",nil];
[alertView show];

}

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)
}

使用Xcode 9和Swift 4.0检查Internet连接的可用性(iOS)

遵循以下步骤

步骤1:

创建一个扩展文件,并将其命名为ReachabilityManager.swift。然后添加下面的代码行。

import Foundation
import SystemConfiguration
public class ConnectionCheck
{
    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)
    }
}

步骤2:使用下面的代码调用上面的扩展。

if ConnectionCheck.isConnectedToNetwork()
{
     print("Connected")
     // Online related Business logic
}
else{
     print("disConnected")
     // Offline related business logic
}

这曾经是正确的答案,但现在已经过时了,因为你应该订阅通知以获得可访问性。这个方法同步检查:


你可以使用苹果的Reachability类。它还可以让你检查是否启用了Wi-Fi:

Reachability* reachability = [Reachability sharedReachability];
[reachability setHostName:@"www.example.com"];    // Set your host name here
NetworkStatus remoteHostStatus = [reachability remoteHostStatus];

if (remoteHostStatus == NotReachable) { }
else if (remoteHostStatus == ReachableViaWiFiNetwork) { }
else if (remoteHostStatus == ReachableViaCarrierDataNetwork) { }

Reachability类并没有随SDK一起发布,而是作为这个Apple示例应用程序的一部分。只需下载它,并复制Reachability.h/m到您的项目。另外,您必须将SystemConfiguration框架添加到您的项目中。

苹果提供了一个示例应用程序,它正是这样做的:

可达性