public static void changeOverTime(final MonitoredVariable<Integer> tVar, final int tTo, final long tTime, final long tUpdateFreq) {
    if (tTime < tUpdateFreq) { Log.e(TAG, "Time must be less then update freq."); }
    if (tVar == null) { Log.e(TAG, "Container cannot be null."); }
    else {
        final Thread tBackgroundThread = new Thread(new Runnable() {
            @Override
            public void run() {
                float tSteps = tTime / tUpdateFreq; // 2000/100 = 20
                float tInterval = (tTo - tVar.get()) / tSteps; // 67-175 = -108/20 = -5.4
                float tVal = tVar.get(); //175
                while (Math.round(tVal) != tTo) { //67(After 20 Times) != 67 -> FALSE
                    Debug.Log(TAG, "EQ: " + Math.round(tVal) + "?=" + tTo);
                    tVal += tInterval; // -5.4 * 20(Times) = -108+175 = 67
                    tryToSleep(tUpdateFreq); // 100ms * 20(Times) = 2000ms total
                    tVar.set(Math.round(tVal));
                }
            }
        });
        tBackgroundThread.start();
    }
}

private static void tryToSleep(long tTime) {
    try { sleep(tTime); }
    catch (InterruptedException e) { e.printStackTrace(); }
}

public class MonitoredVariable<Prototype> {
    protected Prototype mData;
    protected ChangeListener mListener;

    public MonitoredVariable(Prototype tData) {
        this(tData, null);
    }

    public MonitoredVariable(Prototype tData, ChangeListener tListener) {
        if (tListener != null) setListener(tListener);
        mData = tData;
    }

    public Prototype get() {
        return mData;
    }
    public void set(Prototype tData) {
        if (mData != tData) {
            mData = tData;
            notifyChange();
        }
    }

    public void setListener(ChangeListener tListener) {
        mListener = tListener;
    }
    public ChangeListener getListener() {
        return mListener;
    }
    public void notifyChange() {
        if (mListener != null) mListener.onChange();
    }
    public interface ChangeListener {
        void onChange();
    }
}

public static void init() {
    MonitoredVariable.ChangeListener tUpdateBackground = new MonitoredVariable.ChangeListener() {
        @Override
        public void onChange() { updateBackgroud();
        }
    };
    mTop = new MonitoredVariable[]{
            new MonitoredVariable<>(0, tUpdateBackground),
            new MonitoredVariable<>(0, tUpdateBackground),
            new MonitoredVariable<>(0, tUpdateBackground)
    };
    mBottom = new MonitoredVariable[]{
            new MonitoredVariable<>(0, tUpdateBackground),
            new MonitoredVariable<>(0, tUpdateBackground),
            new MonitoredVariable<>(0, tUpdateBackground)
    };


    mAnimationLoop = new Handler();
    mAnimation = new Runnable() {
        @Override
        public void run() {
            Debug.Log(TAG, "RUNNING ANIMATION");
            final Random RNG = new Random();
            for (MonitoredVariable<Integer>[] tBackground: new MonitoredVariable[][] {mTop, mBottom}) {
                for (MonitoredVariable<Integer> tColor : tBackground) {
                    int tRandomColor = RNG.nextInt(255);
                    //tColor.set(tRandomColor);
                    Shift.changeOverTime(tColor, tRandomColor, 2000, 100);
                }
            }
            if(mAnimate.get()) {
                mAnimationLoop.postDelayed(mAnimation, 10000);
            }
        }
    };

    mAnimate = new MonitoredVariable<>(false, new MonitoredVariable.ChangeListener() {
        @Override
        public void onChange() {
            if (mAnimate.get()) mAnimationLoop.postDelayed(mAnimation, 0);
            else mAnimationLoop.removeCallbacks(mAnimation);
        }
    });
}

public static void setBackground(final Activity tActivity){
    final View tActivityBackground = tActivity.findViewById(R.id.background);
    mListener = new ChangeListener() {
        @Override
        public void onChange() { tActivityBackground.setBackground(mBackground); }
    };

    notifyChange();
}

 private static void updateBackgroud() {
    int tTop = Color.argb(255, mTop[0].get(), mTop[1].get(), mTop[2].get());
    int tBottom = Color.argb(255, mBottom[0].get(), mBottom[1].get(), mBottom[2].get());
    int[] colors = {tTop, tBottom};
    mBackground = new GradientDrawable(GradientDrawable.Orientation.TOP_BOTTOM, colors);
    mBackground.setCornerRadius(0f);
    notifyChange();
}

public static void animateBackground(boolean tAnimate) {
    mAnimate.set(tAnimate);
}

public static void notifyChange() {
    if (mListener != null) mListener.onChange();
}

public interface ChangeListener {
    void onChange();
}