Mercury-IM/app/src/main/java/org/mercury_im/messenger/MercuryImApplication.java

package org.mercury_im.messenger;

import android.app.Application;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.content.Context;
import android.content.Intent;
import android.os.Build;

import org.mercury_im.messenger.core.centers.ConnectionCenter;
import org.mercury_im.messenger.core.connection.MercuryConfiguration;
import org.mercury_im.messenger.di.component.AppComponent;
import org.mercury_im.messenger.di.component.DaggerAppComponent;
import org.mercury_im.messenger.di.module.AppModule;
import org.mercury_im.messenger.persistence.room.RoomModule;
import org.mercury_im.messenger.persistence.room.RoomRepositoryModule;
import org.mercury_im.messenger.service.XmppConnectionService;

import javax.inject.Inject;

public class MercuryImApplication extends Application {

    public static final String TAG = "Mercury-IM";

    static {
        // Initialize Smack etc.
        new MercuryConfiguration();
    }

    private static MercuryImApplication INSTANCE;
    AppComponent appComponent;

    public static MercuryImApplication getApplication() {
        return INSTANCE;
    }

    @Inject
    ConnectionCenter connectionCenter;

    @Override
    public void onCreate() {

        super.onCreate();

        INSTANCE = this;

        appComponent = createAppComponent();

        initializeNotificationChannels(this);

        Intent serviceIntent = new Intent(getApplicationContext(), XmppConnectionService.class);

        serviceIntent.setAction(XmppConnectionService.ACTION_START);
        if (Build.VERSION.SDK_INT < 26) {
            startService(serviceIntent);
        } else {
            startForegroundService(serviceIntent);
        }
    }

    /**
     * Create the Dependency Injection graph.
     * For testing, overwrite this method with custom modules.
     */
    public AppComponent createAppComponent() {
        AppComponent appComponent = DaggerAppComponent.builder()
                .appModule(new AppModule(this))
                .roomModule(new RoomModule(this))
                .roomRepositoryModule(new RoomRepositoryModule())
                .build();

        appComponent.inject(this);

        return appComponent;
    }

    public void initializeNotificationChannels(Context context) {
        // Only necessary on Android O and upwards.
        if (Build.VERSION.SDK_INT < 26) {
            return;
        }

        NotificationManager notificationManager =
                (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

        // Foreground notification channel
        String fName = getResources().getString(R.string.channel_name_foreground);
        String fDescription = getResources().getString(R.string.channel_description_foreground);

        NotificationChannel foreground = new NotificationChannel(Notifications.NOTIFICATION_CHANNEL__FOREGROUND_SERVICE,
                fName, NotificationManager.IMPORTANCE_DEFAULT);
        foreground.setDescription(fDescription);
        foreground.setImportance(NotificationManager.IMPORTANCE_MIN);
        foreground.setShowBadge(false);
        notificationManager.createNotificationChannel(foreground);
    }

    public AppComponent getAppComponent() {
        return appComponent;
    }
}