Fading action bar effect using the new Toolbar class from the support library

activity_main.xml

<FrameLayout 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="@null"
    tools:context=".MainActivity">

    <com.github.manuelpeinado.toolbartest.ObservableScrollView
        android:id="@+id/scrollview"
        android:text="@string/hello_world"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fillViewport="true">

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

            <ImageView
                android:id="@+id/header"
                android:layout_height="wrap_content"
                android:layout_width="match_parent"
                android:adjustViewBounds="true"
                android:src="@drawable/nyc" />

            <TextView
                android:layout_height="wrap_content"
                android:layout_width="match_parent"
                android:background="?android:colorBackground"
                android:padding="16dp"
                android:text="@string/loren_ipsum" />

        </LinearLayout>

    </com.github.manuelpeinado.toolbartest.ObservableScrollView>

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:layout_gravity="top"
        android:minHeight="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

</FrameLayout>

MainActivity.java

package com.github.manuelpeinado.toolbartest;

import android.graphics.Color;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.View;

import com.readystatesoftware.systembartint.SystemBarTintManager;


public class MainActivity extends ActionBarActivity implements OnScrollChangedCallback {

    private Toolbar mToolbar;
    private Drawable mActionBarBackgroundDrawable;
    private View mHeader;
    private int mLastDampedScroll;
    private int mInitialStatusBarColor;
    private int mFinalStatusBarColor;
    private SystemBarTintManager mStatusBarManager;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mToolbar = (Toolbar) findViewById(R.id.toolbar);
        mActionBarBackgroundDrawable = mToolbar.getBackground();
        setSupportActionBar(mToolbar);

        mStatusBarManager = new SystemBarTintManager(this);
        mStatusBarManager.setStatusBarTintEnabled(true);
        mInitialStatusBarColor = Color.BLACK;
        mFinalStatusBarColor = getResources().getColor(R.color.primary_color_dark);

        mHeader = findViewById(R.id.header);

        ObservableScrollable scrollView = (ObservableScrollable) findViewById(R.id.scrollview);
        scrollView.setOnScrollChangedCallback(this);

        onScroll(-1, 0);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public void onScroll(int l, int scrollPosition) {
        int headerHeight = mHeader.getHeight() - mToolbar.getHeight();
        float ratio = 0;
        if (scrollPosition > 0 && headerHeight > 0)
            ratio = (float) Math.min(Math.max(scrollPosition, 0), headerHeight) / headerHeight;

        updateActionBarTransparency(ratio);
        updateStatusBarColor(ratio);
        updateParallaxEffect(scrollPosition);
    }

    private void updateActionBarTransparency(float scrollRatio) {
        int newAlpha = (int) (scrollRatio * 255);
        mActionBarBackgroundDrawable.setAlpha(newAlpha);
        mToolbar.setBackground(mActionBarBackgroundDrawable);
    }

    private void updateStatusBarColor(float scrollRatio) {
        int r = interpolate(Color.red(mInitialStatusBarColor), Color.red(mFinalStatusBarColor), 1 - scrollRatio);
        int g = interpolate(Color.green(mInitialStatusBarColor), Color.green(mFinalStatusBarColor), 1 - scrollRatio);
        int b = interpolate(Color.blue(mInitialStatusBarColor), Color.blue(mFinalStatusBarColor), 1 - scrollRatio);
        mStatusBarManager.setTintColor(Color.rgb(r, g, b));
    }

    private void updateParallaxEffect(int scrollPosition) {
        float damping = 0.5f;
        int dampedScroll = (int) (scrollPosition * damping);
        int offset = mLastDampedScroll - dampedScroll;
        mHeader.offsetTopAndBottom(-offset);

        mLastDampedScroll = dampedScroll;
    }

    private int interpolate(int from, int to, float param) {
        return (int) (from * param + to * (1 - param));
    }
}

styles.xml

<resources>

    <style name="AppTheme" parent="Theme.AppCompat.Light">

        <item name="windowActionBar">false</item>
        <item name="android:windowTranslucentStatus">true</item>
        <item name="android:fitsSystemWindows">true</item>

        <item name="colorPrimary">@color/primary_color</item>
        <item name="colorPrimaryDark">@color/primary_color_dark</item>
        <item name="colorAccent">#f77</item>

    </style>

</resources>

If you are only changing the alpha of the background, rather than changing the entire background asset, you could call toolbar.invalidate() after the setAlpha().

this is great just as the play store toolbar behaves but one thing it can't do, it doesn't fades the text in it

It works great but i faced an absurd issue with nexus 5 running lollipop. The toolbar opacity doesn't return back to normal when i exit the activity and return to my previous activity.

I tried calling updateActionBarTransparency(1) on onStop() but still this issue persists. Can anyone help me out?

It works with textview but when i try to replace textview with listview it is not working , is there anyway to implement the same effect for listview ?

It is not working for me because text is going on top of the Picture on scrolling. Can anyone please help?

I was facing this problem because i was not setting the background color of the TextView.

@ramswaroop You could solve the problem calling this code on activity's onResume method:
toolbarBackgroundDrawable.setAlpha(255); // 0% of transparency
toolbar.setBackground(toolbarBackgroundDrawable);

So Android Studio keep saying me:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.vorticelabs.miveo/com.vorticelabs.miveo.activities.VideoViewActivity}: android.view.InflateException: Binary XML file line #9: Error inflating class com.vorticelabs.miveo.activities.ObservableScrollView
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.github.manuelpeinado.toolbartest.ObservableScrollView" on path: DexPathList[[zip file "/data/app/com.vorticelabs.miveo-2/base.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]

Even with the library imported :(

@otozk In xml change com.github.manuelpeinado.toolbartest.ObservableScrollView to com.manuelpeinado.fadingactionbar.view.ObservableScrollView and it should work.

9515-9515/com..apps.material E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NoSuchMethodError: android.support.v7.widget.Toolbar.setBackground
at fragments.Desc2.updateActionBarTransparency(Desc2.java:75)
at fragments.Desc2.onScroll(Desc2.java:66)
at fragments.Desc2.onCreate(Desc2.java:50)
at android.app.Activity.performCreate(Activity.java:4538)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1071)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2161)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2240)
at android.app.ActivityThread.access$600(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1262)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:156)
at android.app.ActivityThread.main(ActivityThread.java:4987)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
at dalvik.system.NativeStart.main(Native Method)

how to use in fragment

@ramswaroop did you solve it? and how ?

How can this be used with a stickey view. i.e. Layout format -> toolbar -> picture holder -> Textview -> rest of listview? When the toolbar is fully opaque, continue to scroll textview on top of it, and make it sticky., while the rest of the listview scrolls under the tool bar.

@ramswaroop @nathaliepl : is there any way to do it without those kinds of hacks? Seems messy to have to do that.

What is min API supported, 11?

Hmm I have quite a complicated list view and can't get this to work (instead of a scroll view), is there any example anywhere?

As per my requirement I have to fix a button at the bottom of the screen,which is visible for all the time so I putted it out of scroll-view. But after doing this I found that there is no fading effect only content inside scroll-view is scroll able even header image-view also stops scrolling. Anyone have any idea why it's not working?

Thanks @ManuelPeinado with this example.
Here is solution to all your problems.

parallax effect on RecyclerView == https://github.com/kanytu/android-parallax-recyclerview

parallax listview, scrollview and gridview with zoom support == https://github.com/kanytu/android-parallax-listview

finally i solve this
do this things 😄

1. Copy Java Code
2. Copy Xml Layout
3. replace com.github.manuelpeinado.toolbartest.ObservableScrollView to com.manuelpeinado.fadingactionbar.view.ObservableScrollView
4. add FadingActionBar library at https://g"ithub.com/ManuelPeinado/
5. add https://github.com/jgilfelt/SystemBarTint library
6. copy Style recource
7. add this for appcompat 22.2 :
   http://stackoverflow.com/questions/29784124/java-lang-illegalargumentexception-appcompat-does-not-support-the-current-theme
8. enjoy it 😊

When redirected to next activity and come back header layout becomes invisible. How to solve this ?

FYI: It's also possible to use the android.support.v4.widget.NestedScrollView bundled in the support library instead of com.github.manuelpeinado.toolbartest.ObservableScrollView.

I'm having the same issue with @ramswaroop, when I go back, the action opacity doesn't return to normal

@nathaliepl thanks for your help it solved my issue.In parent activity just needed to ad this code

public void onResume(){
    super.onResume();
    updateColor();

}

@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
private void updateColor() {
    toolbarBackgroundDrawable.setAlpha(255); // 0% of transparency
    toolbar.setBackground(toolbarBackgroundDrawable);
}