How should I handle “No internet connection” with Retrofit on Android

Question

I\'d like to handle situations when there is no internet connection. Usually I\'d run:

ConnectivityManager cm =
    (ConnectivityManager)context.getSystemSer         


        

Answer 1

With Retrofit 2, we use an OkHttp Interceptor implementation to check for network connectivity ahead of sending the request. If no network, throw an exception as appropriate.

This allows one to specifically handle network connectivity issues before hitting Retrofit.

import java.io.IOException;

import okhttp3.Interceptor;
import okhttp3.Response;
import io.reactivex.Observable

public class ConnectivityInterceptor implements Interceptor {

    private boolean isNetworkActive;

    public ConnectivityInterceptor(Observable isNetworkActive) {
       isNetworkActive.subscribe(
               _isNetworkActive -> this.isNetworkActive = _isNetworkActive,
               _error -> Log.e("NetworkActive error " + _error.getMessage()));
    }

    @Override
    public Response intercept(Interceptor.Chain chain) throws IOException {
        if (!isNetworkActive) {
            throw new NoConnectivityException();
        }
        else {
            Response response = chain.proceed(chain.request());
            return response;
        }
    }
}

public class NoConnectivityException extends IOException {

    @Override
    public String getMessage() {
        return "No network available, please check your WiFi or Data connection";
    }
}