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Poll network continuously for connectivity iphone

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+1 A:

You shouldn't need to poll if you're using the Reachability class. You should be able to set a callback / delegate method on the reachability monitor and get notified when reachability changes.

Something like this:

SCNetworkReachabilitySetCallback(reachability, networkChangedListener, &context);

where 'networkChangedListener` is your callback function. This will be called whenever reachability changes, and from there you can post a notification to let interested parties know.

Jasarien 2010-08-31 13:58:15

Thanx Jasarien.. it helped..

neha 2010-08-31 14:13:45

I have a doubt: Reachability seems to be unreliable as sometimes it displays the network message or just show up a black screen. So do we have a better way? NSUrlConnection seems to be a better option but then what about polling network in that case? Will I need to run a background thread? This seems to be an expensive option. What would be the good practice in this case?

neha 2010-08-31 14:32:53

I haven't had any experiences where Reachability has been unreliable. Do you see it being unreliable in terms of incorrect notifications about network changes or incorrect information on the initial reachability check?

Jasarien 2010-08-31 14:58:18

Reachability callbacks will only tell you if the first hop has been broken. If someone pulls the cable on the other side of your wifi access point, reachability may happily tell you that the network is still reachable. This level of connectivity reporting isn't useful for some application types.

hotpaw2 2010-08-31 16:31:10

I don't believe that's strictly true. Reachability allows you to set a remote host and check the reachability of that host in addition to checking whether the local wifi/network is available.

Jasarien 2010-08-31 18:15:14

@Jasarien I tried using this method but getting an error at "networkChangedListener". Can you please guide, I have done it as follows: struct sockaddr_in zeroAddr;bzero(zeroAddr.sin_len = sizeof(zeroAddr);zeroAddr.sin_family = AF_INET;SCNetworkReachabilityRef target = SCNetworkReachabilityCreateWithAddress(NULL, (struct sockaddr *) SCNetworkReachabilityFlags flags;SCNetworkReachabilityGetFlags(target, SCNetworkReachabilityCallBack(target, flags, networkChangedListener); I'm getting an error "expected ")" before ',' token" at last line.

neha 2010-09-03 09:33:49

`networkChangedLister` is the name of a function that will be called when the network connection changes. You either need to define that function, or create your own and pass it into `SCNetworkReachabilityCallBack()`

Jasarien 2010-09-03 11:15:24

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Poll network continuously for connectivity iphone

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