iOS应用程序没有互联网连接时如何禁用segue？

Question

为了检查Internet连接，我正在考虑通过AppDelegate更新：

1. SystemConfiguration.framework
2. 可达性

为了停止搜寻，我正在考虑使用：

- (BOOL)shouldPerformSegueWithIdentifier:(NSString *)identifier sender:(id)sender

我只想在用户点击UIButton时显示没有互联网连接的警报。

我到底应该做什么

- (void)prepareForSegue:(NSStoryboardSegue *)segue sender:(id)sender

我已经在每个要执行互联网连接检查的ViewController的viewDidLoad方法下注册了通知

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

可达性已更改

- (void) reachabilityChanged: (NSNotification* )note
{
    Reachability* curReach = [note object];
    NSParameterAssert([curReach isKindOfClass: [Reachability class]]);

    NetworkStatus netStatus = [curReach currentReachabilityStatus];
    switch (netStatus)
    {
        case ReachableViaWWAN:
        {
            break;
        }
        case ReachableViaWiFi:
        {
            break;
        }
        case NotReachable:
        {
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Alert" message:@"We are unable to make a internet connection at this time. Some functionality will be limited until a connection is made." delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil];
            [alert show];   
            [alert release];
            break;
        }
    }
}

Answer 1

在类接口中，声明：

@property (nonatomic) BOOL isReachable;

在您的reachabilityChanged方法中：

- (void)reachabilityChanged: (NSNotification* )note
{
    Reachability* curReach = [note object];
    NSParameterAssert([curReach isKindOfClass: [Reachability class]]);

    NetworkStatus netStatus = [curReach currentReachabilityStatus];
    switch (netStatus)
    {
        case ReachableViaWWAN:
        { 
            self.isReachable = YES;
            break;
        }
        case ReachableViaWiFi:
        {
            self.isReachable = YES;
            break;
        }
        case NotReachable:
        {
            self.isReachable = NO;
            break;
        }
    }
}

然后，使用shouldPerformSegueWithIdentifier方法检查是否已连接到Internet。

- (BOOL)shouldPerformSegueWithIdentifier:(NSString *)identifier sender:(id)sender
{
  if ([identifier isEqualToString:YOUR_IDENTIFIER]) {
    if (!self.isReachable) {
       return NO;
    }
  }
return YES;
}