AbstractAnalyticsHelper.java

package com.dgorod.tourbag.presentation.analytics;

import android.support.annotation.NonNull;
import android.support.annotation.Nullable;

/**
 * Created by Dmytro Gorodnytskyi on 30-Apr-16.
 */
public interface AbstractAnalyticsHelper {

    void trackScreen(@NonNull String screenName);

    void trackEvent(@NonNull String category, @NonNull String event);

    void trackEvent(@NonNull String category, @NonNull String event, @Nullable String label);
}

AnalyticsHelper.java

package com.dgorod.tourbag.presentation.analytics;

import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.text.TextUtils;
import android.util.DisplayMetrics;
import android.view.WindowManager;

import com.crashlytics.android.answers.Answers;
import com.crashlytics.android.answers.ContentViewEvent;
import com.crashlytics.android.answers.CustomEvent;
import com.dgorod.tourbag.R;
import com.dgorod.tourbag.commons.Preconditions;
import com.dgorod.tourbag.data.util.Logger;
import com.google.android.gms.analytics.GoogleAnalytics;
import com.google.android.gms.analytics.HitBuilders;
import com.google.android.gms.analytics.Tracker;

/**
 * Singleton to track application analytics with Google Analytics and Crashlytics Answers.
 * Class works like abstract factory and provides real or dummy implementations.
 * If not initialized by {@link #init(Context)} method it will return dummy implementation.
 * Such approach allows to use this class tracking methods in application without changes for
 * cases when analytics should not be gathered. For example, in debug builds.
 *
 * Created by Dmytro Gorodnytskyi on 29-Apr-16.
 */
public class AnalyticsHelper implements AbstractAnalyticsHelper {
    private static final String CATEGORY = "category";
    private static final String LABEL = "label";

    private static Tracker googleTracker;
    private static Answers fabricTracker;
    private static AnalyticsHelper instance;
    private static DummyAnalyticsHelper dummyInstance;

    static {
        dummyInstance = new DummyAnalyticsHelper();
    }

    private AnalyticsHelper(@NonNull Context context) {
        fabricTracker = Answers.getInstance();

        String trackerID = context.getString(R.string.ga_tracker_id);
        String appName = context.getString(R.string.app_name);
        WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
        DisplayMetrics metrics = new DisplayMetrics();
        wm.getDefaultDisplay().getMetrics(metrics);

        googleTracker = GoogleAnalytics.getInstance(context).newTracker(trackerID);
        googleTracker.enableAdvertisingIdCollection(true);
        googleTracker.setUseSecure(true);
        googleTracker.setAppName(appName);
        googleTracker.setScreenResolution(metrics.widthPixels, metrics.heightPixels);

        try {
            PackageInfo pInfo = context.getPackageManager().getPackageInfo(context.getPackageName(), 0);
            googleTracker.setAppVersion(pInfo.versionName);
        }
        catch (PackageManager.NameNotFoundException ex) {
            Logger.e(ex);
        }
    }

    public static synchronized void init(@NonNull Context context) {
        Preconditions.checkNotNull(context);

        if (instance == null) {
            instance = new AnalyticsHelper(context.getApplicationContext());
        }
    }

    @NonNull
    public static synchronized AbstractAnalyticsHelper getInstance() {
        return instance == null ? dummyInstance : instance;
    }

    public void trackScreen(@NonNull String screenName) {
        Preconditions.checkNotNullOrEmpty(screenName);

        fabricTracker.logContentView(new ContentViewEvent().putContentName(screenName));

        googleTracker.setScreenName(screenName);
        googleTracker.send(new HitBuilders.ScreenViewBuilder().build());
    }

    public void trackEvent(@NonNull String category, @NonNull String event) {
        trackEvent(category, event, null);
    }

    public void trackEvent(@NonNull String category, @NonNull String event, @Nullable String label) {
        Preconditions.checkNotNullOrEmpty(category);
        Preconditions.checkNotNullOrEmpty(event);

        CustomEvent fabricEvent = new CustomEvent(event);
        fabricEvent.putCustomAttribute(CATEGORY, category);

        HitBuilders.EventBuilder googleEvent = new HitBuilders.EventBuilder();
        googleEvent.setCategory(category);
        googleEvent.setAction(event);

        if (!TextUtils.isEmpty(label)) {
            fabricEvent.putCustomAttribute(LABEL, label);
            googleEvent.setLabel(label);
        }

        fabricTracker.logCustom(fabricEvent);

        googleTracker.setScreenName(null);
        googleTracker.send(googleEvent.build());
    }
}

DummyAnalyticsHelper.java

package com.dgorod.tourbag.presentation.analytics;

import android.support.annotation.NonNull;
import android.support.annotation.Nullable;

/**
 * Analytics tracker without implementation. Use for cases when analytics should not be gathered.
 *
 * Created by Dmytro Gorodnytskyi on 30-Apr-16.
 */
public class DummyAnalyticsHelper implements AbstractAnalyticsHelper {

    @Override
    public void trackScreen(@NonNull String screenName) { }

    @Override
    public void trackEvent(@NonNull String category, @NonNull String event) { }

    @Override
    public void trackEvent(@NonNull String category, @NonNull String event, @Nullable String label) { }
}