我有这个错误：“无法将 java.lang.String 类型的对象转换为 com.flashpub.flash.imageSection 类型”，我不知道为什么

Question

I've created a listView, and since i'm opening one of the item, the application need to fetch all image of the application, but it's doesn't work, i can't figure it out why that's showing me this error. Thank you for helping !

That's my model on Firebase :

imageSection.java

package com.flashpub.flash;

import java.util.List;

public class imageSection {

    String imageUrl;

    public imageSection(){

    }

    public imageSection(String imageUrl) {
        this.imageUrl = imageUrl;
    }

    public String getImageUrl() {
        return imageUrl;
    }
}

chooseSection.java

package com.flashpub.flash;

import java.util.List;

public class chooseSection {

    String sectionn;

    public chooseSection() {

    }

    public chooseSection(String sectionn) {
        this.sectionn = sectionn;
    }

    public String getSectionn() {
        return sectionn;
    }
}

chooseSectionActivity.java

public class ChooseSectionActivity extends AppCompatActivity {

ListView listView;
FirebaseListAdapter<chooseSection> adapter;
chooseSection sectionChosse;

//private HashMap<Integer, String> allItemsList = new HashMap<Integer, String>();

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

    listView = findViewById(R.id.listView);

    FirebaseDatabase.getInstance().setPersistenceEnabled(true);

    FirebaseDatabase database = FirebaseDatabase.getInstance();
    DatabaseReference myRef = database.getReference();
    myRef.keepSynced(true);

    Query query = FirebaseDatabase.getInstance().getReference().child("Sections");
    Log.i("salut", query.toString());
    FirebaseListOptions<chooseSection> options = new FirebaseListOptions.Builder<chooseSection>()
            .setLayout(R.layout.section_list)
            .setQuery(query,chooseSection.class)
            .build();
    adapter =  new FirebaseListAdapter<chooseSection>(options) {
        @Override
        protected void populateView(@NonNull View view, @NonNull chooseSection model, int position) {

            TextView sectionView = (TextView) view.findViewById(R.id.sectionView);
            sectionView.setText(model.getSectionn());


            chooseSection lu = sectionChosse;
            //String LatLng = lu.getLocationUserLatitude() + "," + lu.getLocationUserLongitude();
            //allItemsList.put(position, model.getSectionn());
        }

    };
    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            //String item = allItemsList.get(position);
            Intent intent = new Intent(ChooseSectionActivity.this, PubsSectionActivity.class);
            //intent.putExtra("key", item);
            startActivity(intent);
        }
    });
    listView.setAdapter(adapter);
}

@Override
protected void onStart() {
    super.onStart();
    adapter.startListening();
}

@Override
protected void onStop() {
    super.onStop();
    adapter.stopListening();
}

}

PubsSectionActivity.java

public class PubsSectionActivity extends AppCompatActivity {
ViewFlipper viewFlipp;
private DatabaseReference databaseReference;
private List<imageSection> slideLists;

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

    viewFlipp = findViewById(R.id.viewFlipper);

    databaseReference = FirebaseDatabase.getInstance().getReference();
    slideLists = new ArrayList<>();
}

@Override
protected void onStart() {
    super.onStart();
    usingFirebaseDatabase();
}

private void usingFirebaseDatabase() {
    String lolipop = "Coiffeur";
    databaseReference.child("Sections/Restaurant")
            .addListenerForSingleValueEvent(new ValueEventListener() {
                @Override
                public void onDataChange(DataSnapshot dataSnapshot) {
                    if (dataSnapshot.exists()) {
                        slideLists.clear();
                        for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                            imageSection model = snapshot.getValue(imageSection.class);
                            slideLists.add(model);
                        }

                        Toast.makeText(PubsSectionActivity.this, "All data fetched", Toast.LENGTH_SHORT).show();
                        usingFirebaseImages(slideLists);
                    } else {
                        Toast.makeText(PubsSectionActivity.this, "No images in firebase", Toast.LENGTH_SHORT).show();
                    }
                }

                @Override
                public void onCancelled(DatabaseError databaseError) {
                    Toast.makeText(PubsSectionActivity.this, "NO images found \n" + databaseError.getMessage(), Toast.LENGTH_SHORT).show();
                }
            });
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

}
private void usingFirebaseImages(List<imageSection> slideLists) {
    for (int i = 0; i < slideLists.size(); i++) {
        String downloadImageUrl = slideLists.get(i).getImageUrl();
        Toast.makeText(this, downloadImageUrl, Toast.LENGTH_LONG).show();
        ImageView imageView = new ImageView(this);
        Picasso.get().load(downloadImageUrl).fit().centerCrop().into(imageView);
        viewFlipp.addView(imageView);
        viewFlipp.setInAnimation(this, android.R.anim.slide_in_left);
        viewFlipp.setOutAnimation(this, android.R.anim.slide_out_right);
    }
}

}

Help me please, i'm stuck !!

i don't know why there is this error...

Answer 1

You're attaching a listener to Sections/Restaurant . Since that is one specific restaurant, you don't need to loop over the children in onDataChange .

So:

databaseReference.child("Sections/Restaurant")
    .addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            if (dataSnapshot.exists()) {
                slideLists.clear();
                imageSection model = snapshot.getValue(imageSection.class);
                slideLists.add(model);
                Toast.makeText(PubsSectionActivity.this, "All data fetched", Toast.LENGTH_SHORT).show();
                usingFirebaseImages(slideLists);
            } else {
                Toast.makeText(PubsSectionActivity.this, "No images in firebase", Toast.LENGTH_SHORT).show();
            }
        }