How to handle java.net.UnknownHostException while using retrofit

android, android-internet

Solution

I think you need to have a retrofit exception in the catch.

catch (RetrofitError error) {
    methodToDeterminErrorType(error);
}

The `RetroFitError` is a generic runtime exception. Once it hits the catch block you can actually verify what kind of a error was actually thrown by retrofit. Retrofit has a method `isNetworkError()` which is what you are probably looking for. So you can basically do something like this:

methodToDetermineErrorType(RetroFitError error) {
if (error.isNetworkType()) {
    // show a toast
   }
}

Hope this helps.

Problem

I'm using retrofit to get and post data from the server. However, if my phone loses internet connection in middle of the app then I see error like this: ``` 05-10 08:12:05.559 29369-29400/? D/Retrofit﹕ java.net.UnknownHostException: Unable to resolve host "my.server.com": No address associated with hostname at java.net.InetAddress.lookupHostByName(InetAddress.java:394) at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236) at java.net.InetAddress.getAllByName(InetAddress.java:214) ``` I would like to handle this error gracefully. I would like to catch the exception and show a toast message like "No internet connection". I'm trying code like this but I get an error that: `java.net.UnknownHostException is never thrown in the try block` ``` try { isTokenValid = MyManager.INSTANCE.getService().validate(); } catch (RetrofitError cause) { Response r = cause.getResponse(); if (r != null && r.getStatus() == 403) { isTokenValid = false; } } catch (UnknownHostException exception) { Toast.makeText(getBaseContext(), "No internet connection", Toast.LENGTH_SHORT).show(); } ```

Original source