标题徽标和标题背景图像在florent37 / MaterialViewPager库中的片段上消失

Question

我正在使用florent37 / MaterialViewPager Library https://github.com/florent37/MaterialViewPager来实现Viewpager。 我有三个选项卡App，Category，Fav。 现在的问题是标题背景在fragement中消失了。当我在Activity中使用它时，它正在工作。 此外，当加载fragement它没有显示标题颜色或背景，但当我滚动它开始显示标题颜色但它没有加载来自Url的背景图像。

我的adpater课程就像这样

public class MyFragmentAdapter extends FragmentStatePagerAdapter {

    public static int pos = 0;
    public static int LEFT_PAGE = 0;
    public static int CENTERED_PAGE = 1;
    public static int RIGHT_PAGE =2;

    private List<Fragment> myFragments;
    private Context context;
    int oldPosition = -1;
    MaterialViewPager materialViewPager;
    public MyFragmentAdapter(Context context, FragmentManager fm,    
List<Fragment> myFrags, MaterialViewPager materialViewPager) {
        super(fm);
         this.myFragments = myFrags;
         this.context = context;
         this.materialViewPager = materialViewPager;
     }

     public void updateData(){
        notifyDataSetChanged();
     }

    @Override
    public Fragment getItem(int position) {
        return myFragments.get(position);

     }

    @Override
    public int getItemPosition(Object object) {

         return POSITION_NONE;
     }

     @Override
     public int getCount() {

         return myFragments.size();
     }



     @Override
      public CharSequence getPageTitle(int position) {

        setPos(position);

         String PageTitle = "";

         switch(pos)
         {
             case 0:
                 PageTitle =  
 context.getResources().getString(R.string.view_pager_apps);
                 break;
             case 1:
                 PageTitle = 
 context.getResources().getString(R.string.view_pager_category);
                 break;
             case 2:
                 PageTitle = 
   context.getResources().getString(R.string.view_pager_fav);
                  break;
          }
         return PageTitle;
      }

     @Override
     public void setPrimaryItem(ViewGroup container, int position, 
 Object object) {
        super.setPrimaryItem(container, position, object);
         //only if position changed
          if(position == oldPosition)
              return;
          oldPosition = position;

          int color = 0;
         String imageUrl = "";
          switch (oldPosition){
             case 0:
                 imageUrl = "http://cdn1.tnwcdn.com/wp-
   content/blogs.dir/1/files/2014/06/wallpaper_51.jpg";
                 color = 
         context.getResources().getColor(R.color.blue);
                     break;
             case 1:
                 imageUrl = 
 "https://fs01.androidpit.info/a/63/0e/android-l-wallpapers-630ea6-
 h900.jpg";
                color = 
 context.getResources().getColor(R.color.green);
                 break;

  case 2:
                  imageUrl = "http://www.droid-life.com/wp-
   content/uploads/2014/10/lollipop-wallpapers10.jpg";

      color = context.getResources().getColor(R.color.cyan);
                  break;
              case 3:
                  imageUrl = "http://www.tothemobile.com/wp-
    content/uploads/2014/07/original.jpg";
                color = context.getResources().getColor(R.color.red);
                break;
         }

          final int fadeDuration = 400;

         //change header's color and image
              materialViewPager.setImageUrl(imageUrl,fadeDuration);

              materialViewPager.setColor(color,fadeDuration);

     }

     public static int getPos() {
        return pos;
     }

     public static void setPos(int pos) {
         MyFragmentAdapter.pos = pos;
    }

 }

以下行没有在那里工作。 materialViewPager.setImageUrl（IMAGEURL，fadeDuration）;

请帮我弄清楚这个问题。这让我痛苦了几天。 ：）