How to handle “no internet connection” scenario when sending requests?

问题

I'm currently developing an instant message application based on FCM (Firebase Cloud Message). My problem lies in the follow scenario:

User is connected to an intermitent network - i.e. a wi-fi that, although holds the connection with the device, might lose internet connection from time to time with the internet provider;
User attempts to send a message (a POST request using volley) when the device is connected to the wi-fi but with no internet connection;

What is the best way to tackle this issue? So far, I've implemented a listener for network change using BroadcastReceiver, however, it is not enough to deal with the scenario described above once the wi-fi connection is not lost.

回答1:

I created my own utility class for that. Whenever I want to make a network call I use the callbacks whenever its a success or a failure. The Library in use is MaterialDialog

public class NetworkUtil {

public static boolean isOnline() {
    InetAddress inetAddress = null;
    try {
        Future<InetAddress> future = Executors.newSingleThreadExecutor().submit(new Callable<InetAddress>() {
            @Override
            public InetAddress call() {
                try {
                    return InetAddress.getByName("google.com");
                } catch (UnknownHostException e) {
                    return null;
                }
            }
        });
        inetAddress = future.get(2000, TimeUnit.MILLISECONDS);
        future.cancel(true);
    } catch (InterruptedException | ExecutionException e) {
        e.printStackTrace();
    } catch (TimeoutException e) {
        e.printStackTrace();
    }
    return inetAddress != null && !inetAddress.equals("");
}


public static MaterialDialog checkConnectivity(final Activity activity, final NetworkUtilCallback callback) {
    MaterialDialog dialog = MaterialDialogUtil.builDialogPositiveNegative(activity,
            activity.getString(R.string.no_internet),
            activity.getString(R.string.instruction_no_internet),
            "RETRY",
            "CANCEL",
            new MaterialDialog.SingleButtonCallback() {
                @Override
                public void onClick(MaterialDialog dialog, DialogAction which) {
                    dialog.dismiss();
                    if (!isOnline()) {
                        checkConnectivity(activity, callback);
                    } else {
                        callback.onSuccess();
                    }
                }
            },
            new MaterialDialog.SingleButtonCallback() {
                @Override
                public void onClick(MaterialDialog dialog, DialogAction which) {
                    dialog.dismiss();
                    callback.onCancel();
                }
            });
    if (!isOnline()) {
        dialog.show();
    } else {
        callback.onSuccess();
    }

    return dialog;
}

public interface NetworkUtilCallback {
    void onSuccess();

    void onCancel();
}

回答2:

In your manifest

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />

And the condition to check before performing server requests!

public static boolean hasInternetConnection()
{
ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo wifiNetwork = cm.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if (wifiNetwork != null && wifiNetwork.isConnected())
{
    return true;
}
NetworkInfo mobileNetwork = cm.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
if (mobileNetwork != null && mobileNetwork.isConnected())
{
    return true;
}
NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
if (activeNetwork != null && activeNetwork.isConnected())
{
    return true;
}
return false;
}

来源：https://stackoverflow.com/questions/38506108/how-to-handle-no-internet-connection-scenario-when-sending-requests

标签

android

android-volley