Gkemon

import java.text.ParseException;
import java.util.Date;

public class ComparableDate implements Comparable<ComparableDate> {
    private Date dateTime;

    public Date getDateTime() {
        return dateTime;
    }

Gkemon

/*This instance of the class show will be registered in the android "Aplpication" instance
like activity.getApplication().registerActivityLifecycleCallbacks(new ApplicationTimeSpentTracker());
*/
public class ApplicationTimeSpentTracker implements Application.ActivityLifecycleCallbacks {
    private int activityReferences = 0;
    private boolean isActivityChangingConfigurations = false;
    private long startingTime;
    private long stopTime;

    @Override

Gkemon

import android.Manifest;
import android.app.Activity;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import java.util.ArrayList;
import java.util.List;

Gkemon

public static void debugLog(String msg){

        final StackTraceElement stackTrace = new Exception().getStackTrace()[1];

        String fileName = stackTrace.getFileName();
        if (fileName == null) fileName="";  // It is necessary if you want to use proguard obfuscation.

        final String info = stackTrace.getMethodName() + " (" + fileName + ":"
                + stackTrace.getLineNumber() + ")";