Android app error while connecting to the internet via the HttpURLConnection function

Question

I have who's function is detecting if the phone's internet connection is available and if it is, whether it can actually connect to the internet or not.

The first part of the code is working well i.e detecting if the phone's mobile data or wi-fi is turned on. If the internet is turned on, the function then tries to connect to a web page using HttpURLConnection to detect if the internet connection can actually access the internet.

Unfortunately, the app keeps on crashing and according to the logcat the error the error is at the line with this code urlc.connect().

as per the logcat, line 21 on MainActivity.java contains this piece of code: utils.network(). Line 93 on Utils.java contains this piece of code: urlc.connect()

public void network() {
    ConnectivityManager cm = (ConnectivityManager)_con.getSystemService(Context.CONNECTIVITY_SERVICE);

    NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
    boolean isConnected = activeNetwork != null && activeNetwork.isConnectedOrConnecting();
    if (isConnected) {
        msg = "Internet Available";
        try {
            HttpURLConnection urlc = (HttpURLConnection)
                    (new URL("http://clients3.google.com/generate_204")
                            .openConnection());
            urlc.setRequestProperty("User-Agent", "Android");
            urlc.setRequestProperty("Connection", "close");
            urlc.setConnectTimeout(1500);
            urlc.connect();
            if (urlc.getResponseCode() == HttpURLConnection.HTTP_OK) {
                msg += " and is connecting.";
            } else {
                msg += " but not connecting";
            }
            Log.e(TAG, "NO Error checking internet connection");
        } catch (IOException e) {
            Log.e(TAG, "Error checking internet connection", e);
        }
    } else {
        msg = "Internet Unavailable";
    }
    Toast toast = Toast.makeText(_con, msg, Toast.LENGTH_LONG);
    toast.show();
}

LOGCAT

09-08 06:02:00.534 4476-4476/com.appsite.appname E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.appsite.appname, PID: 4476
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.appsite.appname/com.appsite.appname.MainActivity}: android.os.NetworkOnMainThreadException
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2572)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2654)
    at android.app.ActivityThread.-wrap11(ActivityThread.java)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1488)
    at android.os.Handler.dispatchMessage(Handler.java:111)
    at android.os.Looper.loop(Looper.java:207)
    at android.app.ActivityThread.main(ActivityThread.java:5728)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)
 Caused by: android.os.NetworkOnMainThreadException
    at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1288)
    at java.net.InetAddress.lookupHostByName(InetAddress.java:432)
    at java.net.InetAddress.getAllByNameImpl(InetAddress.java:253)
    at java.net.InetAddress.getAllByName(InetAddress.java:215)
    at com.android.okhttp.internal.Network$1.resolveInetAddresses(Network.java:29)
    at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:188)
    at com.android.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:157)
    at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:100)
    at com.android.okhttp.internal.http.HttpEngine.createNextConnection(HttpEngine.java:368)
    at com.android.okhttp.internal.http.HttpEngine.nextConnection(HttpEngine.java:351)
    at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:341)
    at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:259)
    at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:454)
    at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:114)
    at com.appsite.appname.utils.Utils.network(Utils.java:93)
    at com.appsite.appname.MainActivity.onCreate(MainActivity.java:21)
    at android.app.Activity.performCreate(Activity.java:6301)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1113)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2519)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2654) 
    at android.app.ActivityThread.-wrap11(ActivityThread.java) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1488) 
    at android.os.Handler.dispatchMessage(Handler.java:111) 
    at android.os.Looper.loop(Looper.java:207) 
    at android.app.ActivityThread.main(ActivityThread.java:5728) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679) 

Answer 1

Try this below line oncreate

StrictMode.ThreadPolicy policy = new
StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);