Reachability在iOS中的真正含义是什么？

Question

我在我的应用程序的代码：

-(void)reachAlert:(Reachability*)currentReach { 

    if(currentReach == hostReach) { 
     //Make sure we have internet connectivity 
     //UIAlertView *internetAlert = [[UIAlertView alloc] initWithTitle:@"Excellent" message:@"Host Reached" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"Ok", nil]; 
     //[internetAlert show]; 
     [[SDSyncEngine sharedEngine] startSync]; 


    } 
    /** 
    if(currentReach == internetReach) { 
    //Make sure we have internet connectivity 
    UIAlertView *internetAlert = [[UIAlertView alloc] initWithTitle:@"Good" 
    message:@"Internet" 
    delegate:self 
    cancelButtonTitle:@"Cancel" 
    otherButtonTitles:@"Ok", nil]; 
    [internetAlert show]; 
    } 
    **/ 
    if(currentReach == wifiReach) { 
     //Make sure we have internet connectivity 
     UIAlertView *internetAlert = [[UIAlertView alloc] initWithTitle:@"Bad News" 
                   message:@"Only wifi" 
                   delegate:self 
                 cancelButtonTitle:@"Cancel" 
                 otherButtonTitles:@"Ok", nil]; 
     [internetAlert show]; 
    } 
    [TestFlight passCheckpoint:@"reachAlert"]; 


} 

正如你可以看到我注释掉internetReach因为我算了一下，什么更重要的是，我们有hostReach。因此，默认情况下我们必须有互联网覆盖。我还评论了hostReach警报仅仅是因为我只想在没有互联网连接的情况下提醒用户。

但是在WiFi测试应用程序时，我得到的坏消息只有WiFi消息。为什么不提供hostReach警报？

Answer 1

可达性是真的不理想用于显示错误消息。理想情况下，当您尝试使用的连接失败时，您应该显示错误消息，例如NSURLConnection返回-1009错误。

Answer 2

不知道是否有帮助，但我发现这个地方，并决定它是一个更好的解决问题的办法 - 尽管有人可能会争辩一下：

- (void) verifyInternetConnection 
{ 
    NSURL *scriptUrl = [NSURL URLWithString:@"http://youtube.com"]; 
    NSData *data = [NSData dataWithContentsOfURL:scriptUrl]; 
    if (!data) 
    { 
     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Internet Required" message:@"This device is not currently connected to the Internet" delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil]; 
     alert.tag = 1; 
     [alert show]; 
    } 
}