Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.app.ActionBar.setBackgroundDrawable(android.graphics.drawable.Drawable)' on a null object reference at com.manuelpeinado.fadingactionbar.extras.actionbarcompat.FadingActionBarHelper.setActionBarBackgroundDrawable(FadingActionBarHelper.java:59) at com.manuelpeinado.fadingactionbar.FadingActionBarHelperBase.initActionBar(FadingActionBarHelperBase.java:173) at com.manuelpeinado.fadingactionbar.extras.actionbarcompat.FadingActionBarHelper.initActionBar(FadingActionBarHelper.java:32) at com.purewow.myapplication.Recipe.onCreate(Recipe.java:20)

Is this a common problem?

Thanks in advance!

I got a problem with a ListView in combination with the FadingActionBar. Once every minute I recalculate the displayed data and call notifyDataSetChanged on the associated adapter.

But every time this happens, the header image gets visible and is visible THROUGH the scrolled list. Only if the list is at its top position, everything stays fine.

Do you have any idea why this happens? Thanks!

Your lib is great but it can be initialized with only resource ids. And you are using setContentView of the activity. So this cannot be used with fragments. Maybe you should have another helper method in which ScrollView and HeaderView are the actual parameters not the ids.

Hello everyone, i'm trying to use the fadingActionBar on my app and i used the code of the SampleFragment.java but i'm having a small issue. as you can see in the image the actionbar is not transparent. what i'm doing wrong? thank you

After notifyDataSetChanged() from LIstAdapter container view is triggered to relayout all children including header view. During relayout it does not keep offset but sets top position based on gravity to 0. After relayout Helper class is notified about new scroll and listview top visible position is not changed so we can just check for that. If header view top position is 0 but previous top position was <0 and listview first visible position haven't changed we can set header offset to last top position.

Just like in the Google Music app, it would be awesome to easily attach "floating" action buttons on top of a list, hovering over the header image but detached from it when you slide your list, so that it basically seems to be linked to the topmost list item. See red rectangle around the button in my screenshot.

If that could also be accomplished by the FadingActionBarHelper - wow! ;-)

Hello,

I would like to use it with HoloEverywhere library (https://github.com/Prototik/HoloEverywhere). When trying to use it, the library send me an error message saying that my activity should be an instance of SherlockActivity (and it is the HoloEverywhere activity...).

Thnks and congrats for yout great work!!

compile 'com.android.support:appcompat-v7:22.0.0'
compile 'com.github.manuelpeinado.fadingactionbar:fadingactionbar-abc:3.1.2'

Even though I used to implement 22.0.0 in my build.gradle, the fadisngactionbar library now overrides the settings to install 23.0.0 library, rendering my app unbuildable due to missing v-23 constants:

http://stackoverflow.com/questions/32092511/resource-error-in-android-studio-after-update-no-resource-found

Im trying to make a header that sometimes is longer then my screen height, but for some reason the screen height of my device seems to be the maximum height the headerview can be.

Is there any workarounds for this? To enable the headerviews height to become greater than the height?

Great library, I'm loving it, but one thing has caught my attention. When scrolling down an activity, if you happen to turn off your screen and then scroll back up, the header image gets misplaced.

Scroll down some and turn off screen..

Scroll back up and you will see this :(

It looks like you're already using Gradle. Accoding to http://gradleplease.appspot.com/ this library is available as an apklib but not aar.

Would you mind adding it?

When I Scroll UP, toolbar is hide. When I Scroll DOWN, it shows toolbar . But when I Scroll DOWN, I want to show toolbar (ScrollState to the top). It have ScrollState.STOP. I thinks to check condition. `implements ObservableScrollViewCallbacks`

toolbar = (Toolbar) findViewById(R.id.tool_bar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
scrollView = (ObservableScrollView) findViewById(R.id.scroll);
scrollView.setScrollViewCallbacks(this);

@Override
public void onScrollChanged(int scrollY, boolean firstScroll, boolean dragging) {

}

@Override
public void onDownMotionEvent() {

}

@Override
public void onUpOrCancelMotionEvent(ScrollState scrollState) {
    ActionBar ab = getSupportActionBar();
    if (ab == null) {
        return;
    }
    if (scrollState == ScrollState.UP) {
        if (ab.isShowing()) {
            ab.hide();
        }
    } else if (scrollState == ScrollState.DOWN) {
        if (!ab.isShowing()) {
            ab.show();
        }
    }
}

I have already integrated this library with an ScrollView in another activity and it works Fine but I also need to use this with and Expandable ListView. There is no scroll on the header image when I try using the code in ListView Activity for my Expandable listview integration.

Can anyone suggest solution please.

Hello Team, I loved the design layouts posted by your team.It would appreciate if you could include the steps to run the code in Android Studio SDK ! Thanks, Irene