Custom parallax collapsing toolbar

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#dedede"
    tools:context="com.example.vaibhav.testingapp.MainActivity">

    <com.example.vaibhav.testingapp.ObservableScrollView
        android:id="@+id/scroll_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:gravity="center_horizontal"
            android:orientation="vertical">

            <LinearLayout
                android:id="@+id/llHeader"
                android:layout_width="match_parent"
                android:layout_height="256dp"
                android:gravity="center_horizontal"
                android:background="@drawable/home_profile_bg"
                android:orientation="vertical"
                android:paddingTop="?attr/actionBarSize">

                <ImageView
                    android:layout_height="150dp"
                    android:layout_width="150dp"
                    android:src="@drawable/shifu_action"
                    android:id="@+id/iv"/>

                <TextView
                    android:text="Some Player"
                    android:textSize="24sp"
                    android:textColor="#fff"
                    android:textStyle="bold"
                    android:layout_height="wrap_content"
                    android:layout_width="wrap_content"/>
            </LinearLayout>

            <android.support.v7.widget.CardView
                android:layout_width="match_parent"
                android:layout_height="300dp"
                app:cardBackgroundColor="#fff"
                android:layout_marginLeft="10dp"
                android:layout_marginRight="10dp"
                android:layout_marginTop="10dp">

                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:orientation="vertical">

                    <TextView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="This text is part of first Cardview\n\n"
                        android:textColor="#ff0000"
                        android:textSize="20sp" />

                </LinearLayout>

            </android.support.v7.widget.CardView>

            <android.support.v7.widget.CardView
                android:layout_width="match_parent"
                android:layout_height="400dp"
                app:cardBackgroundColor="#fff"
                android:layout_marginLeft="10dp"
                android:layout_marginRight="10dp"
                android:layout_marginTop="10dp">

                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:orientation="vertical">

                    <TextView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="This text is part of first Cardview\n\n"
                        android:textColor="#ff0000"
                        android:textSize="20sp" />

                </LinearLayout>

            </android.support.v7.widget.CardView>

            <android.support.v7.widget.CardView
                android:layout_width="match_parent"
                android:layout_height="300dp"
                app:cardBackgroundColor="#fff"
                android:layout_marginLeft="10dp"
                android:layout_marginRight="10dp"
                android:layout_marginTop="10dp">

                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:orientation="vertical">

                    <TextView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="This text is part of first Cardview\n\n"
                        android:textColor="#ff0000"
                        android:textSize="20sp" />

                </LinearLayout>

            </android.support.v7.widget.CardView>

            <android.support.v7.widget.CardView
                android:layout_width="match_parent"
                android:layout_height="400dp"
                app:cardBackgroundColor="#fff"
                android:layout_marginLeft="10dp"
                android:layout_marginRight="10dp"
                android:layout_marginTop="10dp">

                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:orientation="vertical">

                    <TextView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="This text is part of first Cardview\n\n"
                        android:textColor="#ff0000"
                        android:textSize="20sp" />

                </LinearLayout>

            </android.support.v7.widget.CardView>



        </LinearLayout>
    </com.example.vaibhav.testingapp.ObservableScrollView>


    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        app:layout_collapseMode="pin"
        app:theme="@style/ActionbarTheme" />

</RelativeLayout>

ExampleActivity.java

package com.example.vaibhav.testingapp;

import android.graphics.drawable.ColorDrawable;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.animation.AccelerateInterpolator;
import android.view.animation.DecelerateInterpolator;

import com.utils.Logger;
import com.utils.PixelUtils;

public class ExampleActivity extends BaseActivity {

    private int lastScrolledPosition = 0;

    @Override
    protected int getContentView() {

        return R.layout.activity_main;
    }

    @Override
    protected void initViews() {
        final Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);

        setSupportActionBar(toolbar);
        setTitle("Toolbar title");

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        final ColorDrawable cd = new ColorDrawable(getResources().getColor(R.color.main_bg));
        toolbar.setBackgroundDrawable(cd);

        cd.setAlpha(0);

        final int MAX_SCROLL = PixelUtils.dpToPx(220);

        final ScrollViewX scrollView = (ScrollViewX) findViewById(R.id.scroll_view);

        if (scrollView != null) {

            scrollView.setOnScrollViewListener(new ScrollViewX.OnScrollViewListener() {

                @Override
                public void onScrollChanged(ScrollViewX v, int l, int t, int oldl, int oldt) {

                    int scrollY = v.getScrollY();

                    cd.setAlpha(getAlphaforActionBar(scrollY));

                    int diff = scrollY - lastScrolledPosition;


                    if (Math.abs(diff) > 10) {

                        if (diff > 0) {

                            if (scrollY > MAX_SCROLL) {

                                //toolbar.setVisibility(View.GONE);

                                //getSupportActionBar().hide();

                                toolbar.animate().translationY(-toolbar.getBottom()).setInterpolator(new AccelerateInterpolator()).start();
                            }

                        } else {

                            //toolbar.setVisibility(View.VISIBLE);
                            //getSupportActionBar().show();

                            toolbar.animate().translationY(0).setInterpolator(new DecelerateInterpolator()).start();
                        }
                    }

                    lastScrolledPosition = scrollY;

                    /*RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) toolbar.getLayoutParams();
                            layoutParams.topMargin = layoutParams.topMargin - scrollY;

                            if(layoutParams.topMargin < layoutParams.height) {

                                layoutParams.topMargin = - layoutParams.height;
                            }

                            toolbar.setLayoutParams(layoutParams);
                            toolbar.requestLayout();*/
                }

                private int getAlphaforActionBar(int scrollY) {

                    int minDist = 0, maxDist = MAX_SCROLL;

                    Logger.d("Jani scrollY", "Jani : " + scrollY);

                    if (scrollY > maxDist) {

                        return 255;

                    } else if (scrollY < minDist) {

                        return 0;

                    } else {

                        int alpha = 0;

                        alpha = (int) ((255.0 / maxDist) * scrollY);
                        return alpha;
                    }

                }
            });
        }
    }

    @Override
    protected void setTextLabels() {

    }

    @Override
    protected void loadData() {

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        getMenuInflater().inflate(R.menu.menu_home, menu);

        return true;
    }
}

ScrollViewX.java

package com.example.vaibhav.testingapp;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.ScrollView;

public class ScrollViewX extends ScrollView {

    private OnScrollViewListener mOnScrollViewListener;

    public ScrollViewX(Context context) {
        super(context);
    }

    public ScrollViewX(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public ScrollViewX(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public interface OnScrollViewListener {
        void onScrollChanged(ScrollViewX v, int l, int t, int oldl, int oldt);
    }

    public void setOnScrollViewListener(OnScrollViewListener l) {
        this.mOnScrollViewListener = l;
    }

    protected void onScrollChanged(int l, int t, int oldl, int oldt) {
        mOnScrollViewListener.onScrollChanged(this, l, t, oldl, oldt);
        super.onScrollChanged(l, t, oldl, oldt);
    }
}