如何使用可达性类来检测有效的互联网连接?

问题描述

我是 iOS 开发的新手，正在努力让reachability.h 类正常工作.这是我的视图控制器代码:

I'm new to iOS development and am struggling to get the reachability.h class to work. Here is my code for view controller:

- (void)viewWillAppear:(BOOL)animated
{
    [[NSNotificationCenter defaultCenter]
     addObserver:self 
     selector:@selector(checkNetworkStatus:) 
     name:kReachabilityChangedNotification 
     object:nil];

    internetReachable = [Reachability reachabilityForInternetConnection];
    [internetReachable startNotifier];
}

- (void)checkNetworkStatus:(NSNotification *)notice {
    NetworkStatus internetStatus = [internetReachable currentReachabilityStatus];
    NSLog(@"Network status: %i", internetStatus);
}

看起来不错，但在运行应用程序并切换到该视图时，xcode 控制台中没有出现任何内容.

It looks ok but nothing is appearing in the xcode console when running the app and switching to that view.

我正在使用可达性 2.2 和 iOS 4.2.

I'm using Reachability 2.2 and iOS 4.2.

有什么明显的我做错了吗?

Is there something obvious that I am doing wrong?

推荐答案

已如果你想在一些代码执行之前检查可达性，你应该使用

EDITED: If you want to check reachability before some code execution you should just use

Reachability *reachability = [Reachability reachabilityForInternetConnection];    
NetworkStatus internetStatus = [reachability currentReachabilityStatus];
if (internetStatus != NotReachable) {
    //my web-dependent code
}
else {
    //there-is-no-connection warning
}

您还可以在某处添加可达性观察者(即在 viewDidLoad 中):

You can also add a reachability observer somewhere (i.e. in viewDidLoad):

Reachability *reachabilityInfo;
[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(myReachabilityDidChangedMethod)
                                             name:kReachabilityChangedNotification
                                           object:reachabilityInfo];

当您不再需要可达性检测时(即在 dealloc 方法中)，不要忘记调用 [[NSNotificationCenter defaultCenter] removeObserver:self];.

Don't forget to call [[NSNotificationCenter defaultCenter] removeObserver:self]; when you no longer need reachability detection (i.e. in dealloc method).

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