Question

I’m in the middle of debugging an issue where ANR message gets displayed when wi-fi connectivity is lost. So when the application starts it has WI-Fi connectivity. The connectivity drops and during the switching from wi-fi to 3G.. no data can be fetched from the sever. In my code i catch the exception and then after a brief sleep period i try again. But the application displays ANR message and crashes. My question is where should i even begin with. what’s the lead . I looked in the LOGCAT.. but it has no indication which states the application is hanging at a particular place. Any inputs from expert on this.
BTW my devise is Moto Droid Adroid 2.2

Answer 1

Off the top of my head two things could be the problem:

1) You could be getting an ANR because you are doing blocking IO in the UI thread. This is a bad thing as you have discovered. Your solution is to do all blocking IO in separate background threads. Even if this is not directly the case it is still best practice to do IO on a thread separate from the UI thread.

2) The socket is bound to the wifi interface. When that interface is disabled (i.e., connection is lost) that socket is useless. If you are catching exceptions and then just naively attempting to preform another operation on that socket it’s going to throw another exception. This will send your application into an infinite loop of exception catching. You should check the exceptions and throw away the socket appropriately when the network interface is lost.