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

您可以使用Reachability by(可在此处查看)。

#import "Reachability.h"

- (BOOL)networkConnection {
    return [[Reachability reachabilityWithHostName:@"www.google.com"] currentReachabilityStatus];
}

if ([self networkConnection] == NotReachable) { /* No Network */ } else { /* Network */ } //Use ReachableViaWiFi / ReachableViaWWAN to get the type of connection.

其他回答

对于我的iOS项目,我建议使用

可达性类

Swift声明。对我来说,它工作得很好

Wi-Fi和蜂窝数据

import SystemConfiguration

public class Reachability {

    class func isConnectedToNetwork() -> Bool {

        var zeroAddress = sockaddr_in(sin_len: 0, sin_family: 0, sin_port: 0, sin_addr: in_addr(s_addr: 0), sin_zero: (0, 0, 0, 0, 0, 0, 0, 0))
        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 = SCNetworkReachabilityFlags(rawValue: 0)
        if SCNetworkReachabilityGetFlags(defaultRouteReachability!, &flags) == false {
            return false
        }

        let isReachable = (flags.rawValue & UInt32(kSCNetworkFlagsReachable)) != 0
        let needsConnection = (flags.rawValue & UInt32(kSCNetworkFlagsConnectionRequired)) != 0
        let ret = (isReachable && !needsConnection)
        return ret
    }
}

使用条件语句,

if Reachability.isConnectedToNetwork() {
    // Enter your code here
}
}
else {
    print("NO Internet connection")
}

这个类在几乎所有应用程序使用Internet连接的情况下都很有用。 例如,如果条件为真,就可以调用API或执行任务。

首先下载reachability类并放入reachability.h和reachability.h。m文件在你的Xcode。

最好的方法是创建一个通用的Functions类(NSObject),这样你就可以在任何类中使用它。这是检查网络连接可达性的两种方法:

+(BOOL) reachabiltyCheck
{
    NSLog(@"reachabiltyCheck");
    BOOL status =YES;
    [[NSNotificationCenter defaultCenter] addObserver:self
                                          selector:@selector(reachabilityChanged:)
                                          name:kReachabilityChangedNotification
                                          object:nil];
    Reachability * reach = [Reachability reachabilityForInternetConnection];
    NSLog(@"status : %d",[reach currentReachabilityStatus]);
    if([reach currentReachabilityStatus]==0)
    {
        status = NO;
        NSLog(@"network not connected");
    }
    reach.reachableBlock = ^(Reachability * reachability)
    {
        dispatch_async(dispatch_get_main_queue(), ^{
        });
    };
    reach.unreachableBlock = ^(Reachability * reachability)
    {
        dispatch_async(dispatch_get_main_queue(), ^{
        });
    };
    [reach startNotifier];
    return status;
}

+(BOOL)reachabilityChanged:(NSNotification*)note
{
    BOOL status =YES;
    NSLog(@"reachabilityChanged");
    Reachability * reach = [note object];
    NetworkStatus netStatus = [reach currentReachabilityStatus];
    switch (netStatus)
    {
        case NotReachable:
            {
                status = NO;
                NSLog(@"Not Reachable");
            }
            break;

        default:
            {
                if (!isSyncingReportPulseFlag)
                {
                    status = YES;
                    isSyncingReportPulseFlag = TRUE;
                    [DatabaseHandler checkForFailedReportStatusAndReSync];
                }
            }
            break;
    }
    return status;
}

+ (BOOL) connectedToNetwork
{
    // Create zero addy
    struct sockaddr_in zeroAddress;
    bzero(&zeroAddress, sizeof(zeroAddress));
    zeroAddress.sin_len = sizeof(zeroAddress);
    zeroAddress.sin_family = AF_INET;

    // Recover reachability flags
    SCNetworkReachabilityRef defaultRouteReachability = SCNetworkReachabilityCreateWithAddress(NULL, (struct sockaddr *)&zeroAddress);
    SCNetworkReachabilityFlags flags;
    BOOL didRetrieveFlags = SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags);
    CFRelease(defaultRouteReachability);
    if (!didRetrieveFlags)
    {
        NSLog(@"Error. Could not recover network reachability flags");
        return NO;
    }
    BOOL isReachable = flags & kSCNetworkFlagsReachable;
    BOOL needsConnection = flags & kSCNetworkFlagsConnectionRequired;
    BOOL nonWiFi = flags & kSCNetworkReachabilityFlagsTransientConnection;
    NSURL *testURL = [NSURL URLWithString:@"http://www.apple.com/"];
    NSURLRequest *testRequest = [NSURLRequest requestWithURL:testURL  cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:20.0];
    NSURLConnection *testConnection = [[NSURLConnection alloc] initWithRequest:testRequest delegate:self];
    return ((isReachable && !needsConnection) || nonWiFi) ? (testConnection ? YES : NO) : NO;
}

现在您可以通过调用这个类方法来检查任何类中的网络连接。

Pod `Alamofire` has `NetworkReachabilityManager`, you just have to create one function 

func isConnectedToInternet() ->Bool {
        return NetworkReachabilityManager()!.isReachable
}

您可以使用Reachability by(可在此处查看)。

#import "Reachability.h"

- (BOOL)networkConnection {
    return [[Reachability reachabilityWithHostName:@"www.google.com"] currentReachabilityStatus];
}

if ([self networkConnection] == NotReachable) { /* No Network */ } else { /* Network */ } //Use ReachableViaWiFi / ReachableViaWWAN to get the type of connection.

如果你正在使用AFNetworking,你可以使用它自己的实现internet可达状态。

使用AFNetworking的最好方法是子类化AFHTTPClient类,并使用这个类来进行网络连接。

使用这种方法的优点之一是,当可达性状态发生变化时,您可以使用块来设置所需的行为。假设我已经创建了一个名为BKHTTPClient的AFHTTPClient的单例子类(如AFNetworking文档上的“子类注释”所述),我会做如下的事情:

BKHTTPClient *httpClient = [BKHTTPClient sharedClient];
[httpClient setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status)
{
    if (status == AFNetworkReachabilityStatusNotReachable) 
    {
    // Not reachable
    }
    else
    {
        // Reachable
    }
}];

您还可以使用AFNetworkReachabilityStatusReachableViaWWAN和AFNetworkReachabilityStatusReachableViaWiFi枚举来检查Wi-Fi或WLAN连接。