iOS：可达性 - startNotifier在返回应用程序后失败 [英] iOS: Reachability - startNotifier fails after returning to app

问题描述

我的Reachability完全按照主题中的建议工作。

I have Reachability working exactly as suggested as in this thread.

我正在使用开源可达性 。但是我没有使用块而是通知，因此该过程非常类似于Apple的Reachability代码。

I am using the open source Reachability. However I am not using blocks but notifications, hence the process is pretty similar to the Apple's Reachability code.

我第一次启动应用程序时，我运行它并且它可以工作大。

The first time I start the app, I run this and it works great.

Reachability *reachability = [reach hostReachability];
[reachability startNotifier];

reachabilityChanged：事件正在解雇：

The reachabilityChanged: event is firing:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachability_Changed:) name:kReachabilityChangedNotification object:nil];

然而，一旦我按下主页按钮并返回应用程序， startNotifier 在内部返回NO而不是YES。

However once I press the home button and come back to the app, the startNotifier returns internally a NO instead of a YES.

    // Set it as our reachability queue, which will retain the queue
    if(!SCNetworkReachabilitySetDispatchQueue(self.reachabilityRef, self.reachabilitySerialQueue))
    {
#ifdef DEBUG
        NSLog(@"SCNetworkReachabilitySetDispatchQueue() failed: %s", SCErrorString(SCError()));
#endif
      ...
      return NO;

因此上述事件再也不会被解雇。

and hence the event above is never fired again.

除非我错误地使用了这个并且 startNotifier 只能在实例化可达性时在 init 中调用一次再也不会？

Unless I am using this wrongly and startNotifier should only be called once in init when reachability is instantiated and never again?

self.hostReachability = [Reachability reachabilityWithHostname:_HOST];

推荐答案

您只需要拨打 [self.hostReachability startNotifier] 一次在init / load上。以下是基本需求的概要，使用通知而不是链接线程上的块方法：

You should only need to call [self.hostReachability startNotifier] once on init/load. Here's a rundown of your basic needs, using notifications rather than the block method on the linked thread:

1. 添加 tonymillion / Reachability 库到您的项目。

为你的Reachability对象创建属性以确保它被保留，例如。

Create property for your Reachability object to make sure it's retained, eg.

@interface ViewController () {
  NSString *_HOST;
}
@property Reachability *hostReachability;
@end

注册变更通知，并启动通知程序，例如。

Register for change notifications, and start the notifier, eg.

- (void)viewDidLoad
{
  [super viewDidLoad];

  [[NSNotificationCenter defaultCenter] addObserver:self
                                           selector:@selector(reachabilityChanged:)
                                               name:kReachabilityChangedNotification
                                             object:nil];

  _HOST = @"www.google.com";
  self.hostReachability = [Reachability reachabilityWithHostname:_HOST];
  [self.hostReachability startNotifier];
}

- (void)viewDidUnload
{
  [super viewDidUnload];

  [[NSNotificationCenter defaultCenter] removeObserver:self];
}

最后，创建一个 reachabilityChanged：处理对可达性更改的响应的方法，例如。

Finally, create a reachabilityChanged: method to handle your response to Reachability changes, eg.

- (void)reachabilityChanged:(NSNotification*)notification
{
  Reachability *notifier = [notification object];
  NSLog(@"%@", [notifier currentReachabilityString]);
}

注意：如果你按Home键并卸载应用程序，Reachability中的更改应在返回应用程序后立即触发通知。

Note: If you press the Home button and unload the app, changes in Reachability should fire a notification immediately upon returning to the app.

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