向RestAPI Android请求数据时如何处理Internet连接

Question

I have asynctask for requesting JSON file from RestAPI, the problem is before webservice send JSON data, my connection have been lost, and get error because of that. I already have ConnectivityManager to check if connection establish i can run the asynctask for requesting JSON. How to handle when asynctask is already running?

This is my ConnectivityManager function:

public bool isOnline()
        {
            ConnectivityManager cm = (ConnectivityManager)GetSystemService(ConnectivityService);
            NetworkInfo activeConnection = cm.ActiveNetworkInfo;
            return activeConnection != null && activeConnection.IsConnected;

        }

I'm using Visual Studio 2015 and Xamarin to build Android App.

Thanks in advance

Answer 1

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

/**
 * Net Utils for android
 */
public class NetUtils { 

    /**
     * @param context the context you're checking connectivity for
     * @return true if the application can access the internet
     */
    public static boolean hasConnectivity(Context context, boolean roamingOK) {
        boolean hasConnectivity = true;
        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo info = connectivityManager.getActiveNetworkInfo();
        hasConnectivity = info != null && (info.isConnected() || (roamingOK && info.isRoaming()));
        return hasConnectivity;
    }

}

also add permission on manifest

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