AndroidManifest.xml

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<application
.
.
>
<receiver android:name=".Receivers.NetworkConnectivityChangeReceiver">
            <intent-filter>
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
            </intent-filter>
</receiver>            
.
.
/>

Log

Process: org.fossasia.openevent, PID: 4413
                                                 java.lang.RuntimeException: Error receiving broadcast Intent { act=android.net.conn.CONNECTIVITY_CHANGE flg=0x4000010 (has extras) } in org.fossasia.openevent.Receivers.NetworkConnectivityChangeReceiver@8a12e8b
                                                     at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:891)
                                                     at android.os.Handler.handleCallback(Handler.java:739)
                                                     at android.os.Handler.dispatchMessage(Handler.java:95)
                                                     at android.os.Looper.loop(Looper.java:148)
                                                     at android.app.ActivityThread.main(ActivityThread.java:5417)
                                                     at java.lang.reflect.Method.invoke(Native Method)
                                                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
                                                  Caused by: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
                                                     at android.support.v7.app.AppCompatDelegateImplV7.createSubDecor(AppCompatDelegateImplV7.java:310)
                                                     at android.support.v7.app.AppCompatDelegateImplV7.ensureSubDecor(AppCompatDelegateImplV7.java:279)
                                                     at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:253)
                                                     at android.support.v7.app.AppCompatDialog.setContentView(AppCompatDialog.java:76)
                                                     at android.support.v7.app.AlertController.installContent(AlertController.java:213)
                                                     at android.support.v7.app.AlertDialog.onCreate(AlertDialog.java:240)
                                                     at android.app.Dialog.dispatchOnCreate(Dialog.java:394)
                                                     at android.app.Dialog.show(Dialog.java:295)
                                                     at org.fossasia.openevent.Receivers.NetworkConnectivityChangeReceiver.onReceive(NetworkConnectivityChangeReceiver.java:50)
                                                     at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:881)
                                                     at android.os.Handler.handleCallback(Handler.java:739) 
                                                     at android.os.Handler.dispatchMessage(Handler.java:95) 
                                                     at android.os.Looper.loop(Looper.java:148) 
                                                     at android.app.ActivityThread.main(ActivityThread.java:5417) 
                                                     at java.lang.reflect.Method.invoke(Native Method) 
                                                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
                                                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

NetworkConnectivityChangeReceiver.java

package org.fossasia.openevent.Receivers;

import android.app.Dialog;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.provider.Settings;

import org.fossasia.openevent.OpenEventApp;
import org.fossasia.openevent.R;
import org.fossasia.openevent.events.ConnectionCheckEvent;
import org.fossasia.openevent.widget.DialogFactory;

import timber.log.Timber;

/**
 * User: Harshit Dwivedi
 * Date: 02/03/16
 * <p/>
 * Network connectivity change receiver to detect changes in network
 */
public class NetworkConnectivityChangeReceiver extends BroadcastReceiver {

    public boolean isConnected = false;

    @Override
    public void onReceive(final Context context, final Intent intent) {
        Timber.i("Network information received %s", intent);
        ConnectionCheckEvent event = new ConnectionCheckEvent(isConnected);
        Dialog d = DialogFactory.createSimpleActionDialog(context,
                R.string.net_unavailable,
                R.string.turn_on,
                new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Intent setNetworkIntent = new Intent(Settings.ACTION_SETTINGS);
                        context.startActivity(setNetworkIntent);
                    }
                });
        if (isNetworkAvailable(context)) {
            if (!event.connState()) {
                event.isConnected = true;
                d.hide();
            }
        } else {
            event.isConnected = false;
            d.show();
        }
        Timber.i("Network connected %s", event.isConnected);
        OpenEventApp.postEventOnUIThread(event);
    }

    private boolean isNetworkAvailable(Context context) {
        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
        return (networkInfo != null && networkInfo.isConnected());
    }
}