Change the background color of an AppBar.

[richardromero]

I have this tablayout with three fragments inside of an Appbar. When I change the current tab I want to change the background color of the appbar too. The code bellow is not working very well because not always the background color is setted correctly. I mean, the color that should be setted to artist is setted to track, or the album background color is setted in artist tab, something like that. And when I start the app no background color is setted.

How can I fix this?

colors.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
   <color name="app_bar_artist">#FFF29312</color>
   <color name="app_bar_album">#FFEDEFEB</color>
   <color name="app_bar_track">#FF3E86A0</color>
</resources>

main_activity.xml

<android.support.design.widget.AppBarLayout
   android:id="@+id/activity_main_app_bar_layout"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:layout_weight="20">

   <include
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       layout="@layout/toolbar_layout"/>

   <android.support.design.widget.TabLayout
       android:id="@+id/activity_main_tab_layout"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:layout_below="@+id/activity_main_app_bar_layout"
       app:tabGravity="fill"
       app:tabMode="fixed"/>

</android.support.design.widget.AppBarLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity {
   private AppBarLayout appbar;

   // others implementations here but not related to the problem.
   public void setTabLayout() {
       ArtistFragment artistFragment = new ArtistaFragment();
       AlbumFragment   albumFragment   = new AlbumFragment();
       TrackFragment  trackFragment  = new TrackFragment();

       artistFragment.setAppBarLayout(appbar);
       albumFragment.setAppBarLayout(appbar);
       trackFragment.setAppBarLayout(appbar);

       viewPagerAdapter.addFragment(artistFragment, getResources().getString(R.string.fragment_artist_title));
       viewPagerAdapter.addFragment(albumFragment,   getResources().getString(R.string.fragment_album_title));
       viewPagerAdapter.addFragment(trackFragment,  getResources().getString(R.string.fragment_track_title));

       viewPager.setAdapter(viewPagerAdapter);
       tabLayout.setupWithViewPager(viewPager);
   }

   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_main);
       appbar    = findViewById(R.id.activity_main_app_bar_layout);
       // others implementations here but not related to the problem.
       setTabLayout();
   }
}

ArtistFragment.java

public class ArtistFragment extends Fragment {

   private AppBarLayout appBarLayout;

   public ArtistFragment() {}

   public void setAppBarLayout(AppBarLayout appBarLayout) {
       this.appBarLayout = appBarLayout;
   }

   private void setBackgroundColor() {
       appBarLayout.setBackgroundColor(getResources().getColor(R.color.app_bar_artist));
   }

   @Override
   public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
       View view = inflater.inflate(R.layout.fragment_artist, container, false);
       setBackgroundColor();
       return view;
   }

}

AlbumFragment.java

public class AlbumFragment extends Fragment {

   private AppBarLayout appBarLayout;

   public AlbumFragment() {}

   public void setAppBarLayout(AppBarLayout appBarLayout) {
       this.appBarLayout = appBarLayout;
   }

   private void setBackgroundColor() {
       appBarLayout.setBackgroundColor(getResources().getColor(R.color.app_bar_album));
   }

   @Override
   public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
       View view = inflater.inflate(R.layout.fragment_album, container, false);
       setBackgroundColor();
       return view;
   }

}

I didn't post TrackFragment because is almost the same code as ArtistFragment and AlbumFragment.