FireBase 实时数据库在第二个视图中为空答案

【问题标题】：FireBase Realtime Datasbase is empty on second viewFireBase 实时数据库在第二个视图中为空
【发布时间】：2017-08-24 11:57:07
【问题描述】：

我在使用通过适配器显示带有 Firebase 实时数据库项目的 Listview 的片段时遇到问题。当我第一次打开片段时，它会按原样显示所有内容，但是当我转到另一个片段并第二次打开第一个片段时，它保持为空。如下图所示。

Problem with empty fragment

这是我的代码：

表格布局片段：

public class Stand_Fragment extends Fragment {

DatabaseReference mDatabase;
Toolbar toolbar;
TabLayout tabLayout;
ViewPager viewPager;
Stand_ViewPager standViewPager;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View View = inflater.inflate(R.layout.fragment_stand, container, false);

    getActivity().setTitle("Stand");

    tabLayout = (TabLayout)View.findViewById(R.id.tabLayout_stand);
    viewPager = (ViewPager) View.findViewById(R.id.viewPager_stand);

    toolbar = (Toolbar) View.findViewById(R.id.toolbar_stand);
    ((AppCompatActivity)getActivity()).setSupportActionBar(toolbar);

    tabLayout = (TabLayout)View.findViewById(R.id.tabLayout_stand);
    viewPager = (ViewPager) View.findViewById(R.id.viewPager_stand);
    standViewPager = new Stand_ViewPager(getFragmentManager());
    standViewPager.addFragments(new StandBeker_Fragment(), "Beker");
    standViewPager.addFragments(new StandCompetitie_Fragment(), "Competitie");
    standViewPager.addFragments(new StandBeker_Fragment_Admin(), "Admin Beker");
    standViewPager.addFragments(new StandCompetitie_Fragment_Admin(), "Admin Competitie");

    tabLayout.setTabTextColors(ColorStateList.valueOf(Color.parseColor("#ffffff")));
    viewPager.setAdapter(standViewPager);
    tabLayout.setupWithViewPager(viewPager);

    return View;
}
}

显示列表视图的片段：

 public class StandBeker_Fragment extends Fragment {

private DatabaseReference mDatabaseRef;
private List<ImageUpload> imgList;
private ListView lv;
private StandBeker_Adapter adapter;
private ProgressDialog progressDialog;

public StandBeker_Fragment(){
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    final View View = inflater.inflate(R.layout.activity_image_list, container, false);

    imgList = new ArrayList<>();
    lv = (ListView) View.findViewById(R.id.ListViewImage);

    progressDialog = new ProgressDialog(getActivity());
    progressDialog.setMessage("Aan het laden...");
    progressDialog.show();

    mDatabaseRef = FirebaseDatabase.getInstance().getReference(StandBeker_Fragment_Admin.FB_DATABASE_PATH);
    mDatabaseRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            progressDialog.dismiss();

            for(DataSnapshot snapshot : dataSnapshot.getChildren()) {
                ImageUpload img = snapshot.getValue(ImageUpload.class);
                        imgList.add(img);
            }
            adapter = new StandBeker_Adapter(getActivity(), R.layout.fragment_stand_beker, imgList);
            lv.setAdapter(adapter);
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
        }
    });

    return View;
}
}

列表视图的适配器类：

public class StandBeker_Adapter extends ArrayAdapter<ImageUpload> {
private Activity context;
private int resource;
private List<ImageUpload> listImage;

public StandBeker_Adapter(@NonNull Activity context, @LayoutRes int resource, @NonNull List<ImageUpload> objects) {
    super(context, resource, objects);
    this.context = context;
    this.resource = resource;
    listImage = objects;
}

@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
    LayoutInflater inflater = context.getLayoutInflater();

    View v = inflater.inflate(resource, null);
    TextView tvName = (TextView) v.findViewById(R.id.tvImageName);
    ImageView img = (ImageView) v.findViewById(R.id.imgView);

    tvName.setText(listImage.get(position).getName());
    Glide.with(context).load(listImage.get(position).getUrl()).into(img);

    return v;
}
}

我的日志：

                                                                   [ 08-24 12:12:06.779 12936:12986 D/         ]

    HostConnection::get() New Host Connection established 0x939ca540, tid 12986


                                                               [ 08-24 
    12:12:06.781 12936:12986 W/         ]
                                                               Unrecognized GLES 
     max version string in extensions: ANDROID_EMU_CHECKSUM_HELPER_v1 ANDROID_EMU_dma_v1 
    08-24 12:12:06.783 12936-12986/kelseyvanderheijden.vvop6 I/OpenGLRenderer: Initialized EGL, version 1.4
08-24 12:12:06.783 12936-12986/kelseyvanderheijden.vvop6 D/OpenGLRenderer: Swap behavior 1
08-24 12:12:06.783 12936-12986/kelseyvanderheijden.vvop6 W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
08-24 12:12:06.783 12936-12986/kelseyvanderheijden.vvop6 D/OpenGLRenderer: Swap behavior 0
08-24 12:12:06.786 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglCreateContext: 0xa04301e0: maj 2 min 0 rcv 2
08-24 12:12:06.806 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:06.900 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:06.983 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:07.035 12936-12936/kelseyvanderheijden.vvop6 W/art: Before Android 4.1, method int android.support.v7.widget.ListViewCompat.lookForSelectablePosition(int, boolean) would have incorrectly overridden the package-private method in android.widget.ListView
08-24 12:12:07.047 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:07.078 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:07.106 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:07.564 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:11.759 12936-12981/kelseyvanderheijden.vvop6 V/FA: Inactivity, disconnecting from AppMeasurementService
08-24 12:12:16.570 12936-12964/kelseyvanderheijden.vvop6 W/DynamiteModule: Local module descriptor class for com.google.firebase.auth not found.
08-24 12:12:35.114 12936-12941/kelseyvanderheijden.vvop6 I/art: Do partial code cache collection, code=30KB, data=30KB
08-24 12:12:35.114 12936-12941/kelseyvanderheijden.vvop6 I/art: After code cache collection, code=30KB, data=30KB
08-24 12:12:35.114 12936-12941/kelseyvanderheijden.vvop6 I/art: Increasing code cache capacity to 128KB
08-24 12:12:37.186 12936-12936/kelseyvanderheijden.vvop6 I/AppCompatViewInflater: app:theme is now deprecated. Please move to using android:theme instead.
08-24 12:12:37.353 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.367 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.379 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.386 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.395 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.412 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.419 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.428 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.439 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.449 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.452 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.455 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.464 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.467 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.470 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.478 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.482 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.485 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.496 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.501 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.503 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.510 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.515 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.518 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.526 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.529 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.533 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.543 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.548 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.550 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.560 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.565 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.568 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.578 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.584 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.588 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.599 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.604 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.612 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.620 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.624 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.633 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.637 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.646 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.652 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.660 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.666 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.676 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.683 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.692 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.699 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.709 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.713 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.726 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.732 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.743 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.750 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.759 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.763 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.777 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.782 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.792 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.796 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.809 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.815 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.826 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.833 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.842 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.849 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.860 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.864 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.876 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.881 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.894 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.899 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.909 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.920 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.926 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.930 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.943 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.948 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.958 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.963 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.976 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.980 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.993 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:37.999 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.009 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.014 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.027 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.035 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.043 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.047 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.060 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.066 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.076 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.082 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.092 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.100 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.110 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.115 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.127 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.132 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.143 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.147 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.159 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.165 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.176 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.180 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.191 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.198 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.211 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.216 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.227 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.232 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.242 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.249 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.260 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.264 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.277 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.284 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.292 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.299 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.310 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.322 12936-12941/kelseyvanderheijden.vvop6 I/art: Do partial code cache collection, code=61KB, data=61KB
08-24 12:12:38.326 12936-12941/kelseyvanderheijden.vvop6 I/art: After code cache collection, code=61KB, data=61KB
08-24 12:12:38.326 12936-12941/kelseyvanderheijden.vvop6 I/art: Increasing code cache capacity to 256KB
08-24 12:12:38.346 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:38.402 12936-12943/kelseyvanderheijden.vvop6 W/art: Suspending all threads took: 9.810ms
08-24 12:12:38.417 12936-12986/kelseyvanderheijden.vvop6 D/EGL_emulation: eglMakeCurrent: 0xa04301e0: ver 2 0 (tinfo 0xa213d270)
08-24 12:12:44.946 12936-12936/kelseyvanderheijden.vvop6 I/AppCompatViewInflater: app:theme is now deprecated. Please move to using android:theme instead.

我做错了什么？非常感谢！

【问题讨论】：

切换选项卡时，Logcat 中是否出现任何可疑情况？
感谢您的回答。我不知道。我已将 logcat 添加到帖子中。你有什么想法吗？
那些是切换标签时出现的日志吗？当您第二次按下选项卡时，我有兴趣查看 Logcat 中打印的内容（并且没有显示任何内容）。您似乎正确地从 Firebase 读取数据（正如您第一次看到它显示的那样），我认为您的问题是由适配器或选项卡片段代码引起的
这些是fragment和不在tablayout中的fragment之间切换的日志。当我在选项卡之间切换时，不会出现问题。仅当我转到完整的其他片段时才会发生这种情况。例如（见截图图片）：[当我在 Home-fragment 时] -> 然后我去 Stand-fragment（它有效） -> 然后我再次去 Home-fragment（一切都很好） ->然后我去Stand-fragment（此时它不再显示列表视图）
您的StandBeker_Fragment 课程有问题。只是我不知道是什么

标签： android listview android-fragments firebase-realtime-database adapter

【解决方案1】：

将用于从 Firebase 获取数据的代码从 onCreateView 方法移至 onResume() 方法。

@Override
public void onResume() {
    super.onResume();

    progressDialog = new ProgressDialog(getActivity());
    progressDialog.setMessage("Aan het laden...");
    progressDialog.show();

    mDatabaseRef = FirebaseDatabase.getInstance().getReference(StandBeker_Fragment_Admin.FB_DATABASE_PATH);
    mDatabaseRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            progressDialog.dismiss();

            for(DataSnapshot snapshot : dataSnapshot.getChildren()) {
                ImageUpload img = snapshot.getValue(ImageUpload.class);
                        imgList.add(img);
            }
            adapter = new StandBeker_Adapter(getActivity(), R.layout.fragment_stand_beker, imgList);
            lv.setAdapter(adapter);
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
        }
    });

}

【讨论】：

感谢您的回答。我想到了这个（我刚刚又试了一次），但不幸的是这并没有解决问题。
在onCreateView() 中添加断点并调试应用程序。查看方法是否被调用。
我不认为它被调用了。 08-24 13:27:12.061 1184-1184/kelseyvanderheijden.vvop6 I/AppCompatViewInflater: app:theme is now deprecated. Please move to using android:theme instead.