Need some help with Reachability (2.0.3ddg)

问题

When my app launches, I check for reachability because I need an immediate internet connection. My problem, though, is that it appears there's no immediate confirmation for the NetworkStatus, which means right after the Reachability is setup, I check whether there's a connection, and it returns that there isn't, regardless of whether I am in fact on WiFi/3G, or have turned the radio off.

I can confirm that I am in fact getting an Internet connection, because instantly after applicationDidFinishLaunching, there's a notification which then logs "ReachableViaWiFi"..

What am I doing wrong? Why is it not confirming a valid Internet connection right away?

- (void)applicationDidFinishLaunching:(UIApplication *)application {    
    NetworkStatus netStatus = [hostReach currentReachabilityStatus];
    if (netStatus == NotReachable) {
        ErrorViewController *errorViewController = [[ErrorViewController alloc] initWithNibName:@"ErrorView" bundle:[NSBundle mainBundle]];
        [tabBarController.view removeFromSuperview];
        [window addSubview:[errorViewController view]];
        return;
    }
}

-(void)setupReachability {
    [[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(reachabilityChanged:) name:kReachabilityChangedNotification object: nil];
    hostReach = [[Reachability reachabilityWithHostName:@"www.google.com"] retain];
    [hostReach startNotifier];
}

-(void)reachabilityChanged:(NSNotification *)notification {
    Reachability* curReach = [notification object];
    NSParameterAssert([curReach isKindOfClass: [Reachability class]]);
    NetworkStatus netStatus = [curReach currentReachabilityStatus];
    BOOL connectionRequired = [curReach connectionRequired];
    switch (netStatus)
    {
        case NotReachable:
        {
            [[NSUserDefaults standardUserDefaults] setInteger:kNOTREACHABLE forKey:kREACHABILITYSTATUS];
            NSLog(@"NotReachable");
            connectionRequired = NO;  
            break;
        }

        case ReachableViaWWAN:
        {
            [[NSUserDefaults standardUserDefaults] setInteger:kREACHABLEVIAWWAN forKey:kREACHABILITYSTATUS];
            NSLog(@"ReachableViaWWAN");
            break;
        }
        case ReachableViaWiFi:
        {
            [[NSUserDefaults standardUserDefaults] setInteger:kNOTREACHABLE forKey:kREACHABILITYSTATUS];
            NSLog(@"ReachableViaWiFi");
            break;
        }
    }
}

回答1:

OK, so after trying a few things out myself, I actually got it to work, by adding one extra line of code:

-(void)setupReachability {
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged:) name:kReachabilityChangedNotificationV2 object:nil];
    hostReach = [[ReachabilityV2 reachabilityWithHostName:@"www.google.com"] retain];
    [hostReach connectionRequired]; // this line was added, and apparently forces a connection requirement..
    [hostReach startNotifier];
}

回答2:

The Reachability sample code provides you with asynchronous callbacks/notifications to inform you of how/when the reachability has changed. In order for your code to work, you should modify your code as follows:

- (void) applicationDidFinishLaunching:(UIApplication *)application {

 // setup reachability
    [self setupReachability];
 }

Then in your callback, when you get the notification you react as needed by your application.

In other words, you can not check immediately for the network status in applicationDidFinishLaunching(). If you want to do so, then you must use a synchronous/blocking method, for instance you can use the code provided in my answer to this question.

回答3:

You have to make hostReach as class level variable.

来源：https://stackoverflow.com/questions/2156375/need-some-help-with-reachability-2-0-3ddg

标签

iphone

objective-c

reachability