yuriyskulskiy

   public void applyParallax(float translateValue) {
        mBackgroundImg.setTranslationY(translateValue - this.getHeight() / 8f);
        mTitleTV.setTranslationY(+translateValue * 2);
        mProfileCircleIV.setTranslationY(translateValue * 2);
        mWeatherIcon.setTranslationY(translateValue * 2);
    }

yuriyskulskiy

   @Override
    public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler,
                                  RecyclerView.State state) {
        ...
        if (parentLayout != null) {
            animatedLayout = parentLayout.findViewById(R.id.transformItem);
            float translateValue = computeCurrentParallaxOffset(parentLayout);
            animatedLayout.applyParallax(translateValue);
        }
        ...

yuriyskulskiy

public class AnimatedLayout extends ConstraintLayout {
  ...
    private void applySummerTitleTV() {
        mTitleTV.setBackgroundResource(R.drawable.summer_text_background);
        mTitleTV.setTextColor(Color.BLACK);
        mTitleTV.setText("WINTER IS COMING...");

        // fix bug: text view with wrap_content layout param
        // does not resize its width and
        // last word of new text will not displayed if new string is longer

yuriyskulskiy

...
private int mIdleState = SUMMER_STATE; // set initial state as SUMMER_STATE
...

    public void animateBy(int dy) {
        float newOffset;
        if (dy > 0) {
            newOffset = (mOffsetValue - dy) < 0 ? 0 : mOffsetValue - dy;
        } else {
            //scroll to the left

yuriyskulskiy

public class CustomLinearLayoutManager extends LinearLayoutManager {
    public CustomLinearLayoutManager(Context context) {
        super(context);
    }

    public CustomLinearLayoutManager(Context context, int orientation, boolean reverseLayout) {
        super(context, orientation, reverseLayout);
    }

    public CustomLinearLayoutManager(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {

yuriyskulskiy

 private void init() {
        ...
        mFling.addEndListener(new DynamicAnimation.OnAnimationEndListener() {
            @Override
            public void onAnimationEnd(DynamicAnimation animation, boolean canceled, float value, float velocity) {
                if (!canceled) {
                    if (mOffsetValue == 0 || mOffsetValue == getWidth()) {
                        //correct ending
                        mCurrentAnimation = IDLE_ANIMATION_STATE;
                        if (mOffsetValue == 0) {

yuriyskulskiy

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        isTouching = true;
        mFling.cancel();
        switch (event.getActionMasked()) {
            case MotionEvent.ACTION_DOWN:
                mPreviousTouchX = event.getX();
                if (mVelocityTracker == null) {
                    // Retrieve a new VelocityTracker object to watch the velocity
                    // of a motion.

yuriyskulskiy

    private float MIN_FLING_START_VELOCITY_DP = 500;

    private float mCurrentMinFlingVelocityPx;
    private VelocityTracker mVelocityTracker;
    private boolean isTouching = false;
    private FlingAnimation mFling = new FlingAnimation(this,
            new FloatPropertyCompat<AnimatedLayout>("offset") {

                @Override
                public float getValue(AnimatedLayout object) {

yuriyskulskiy

    private void updateOffset(float newOffsetValue) {
        ...
        updateIconView();
    }

    private void updateIconView() {
        float oldTranslatePosition = mWeatherIcon.getTranslationX();
        float newTranslatePosition;
        float newAlpha;

yuriyskulskiy

public class AnimatedLayout extends ConstraintLayout {
    ...
    @Override
    protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
        if (canvas instanceof ScreenShotCanvas) {
            if (isChildExcluded(child)) {
                // do not draw this child to the screenshot canvas
                return false;
            }
            return super.drawChild(canvas, child, drawingTime);