Question

我正在尝试使用Firebase实时数据库实现多个视图或所谓的异构recyclerview。我在github上找到了一个异构recyclerview实现的示例。

我遵循此步骤在firebase上实现。但是我的代码不起作用。

fragment_search.java（我的选项卡式视图中的片段之一）。这是我的片段文件，其中包含将包含多个视图的主recyclerview

public class fragment_search extends Fragment {

RecyclerView recyclerViewSearch;

private static SingleSearchBannerModel singleSearchBannerModel;
private static SingleSearchType1Model singleSearchType1Model;

private static DatabaseReference databaseReference;

private List<Object> objects = new ArrayList<>();

private static SearchMainAdapter searchMainAdapter;

@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_search,null);

    //Recycler view initialized and Properties Set.
    recyclerViewSearch = view.findViewById(R.id.recyclerview_search);
    recyclerViewSearch.setHasFixedSize(true);
    recyclerViewSearch.setLayoutManager(new LinearLayoutManager(getContext()));

    databaseReference = FirebaseDatabase.getInstance().getReference();
    return view;
}


private List<Object> getObjects(){
    objects.addAll(getBannerData());
    objects.addAll(getType1Data());
    return objects;
}

public static List<SingleSearchBannerModel> getBannerData(){
    final List<SingleSearchBannerModel> singleSearchBannerModelList = new ArrayList<>();
    databaseReference.child("Featured").addChildEventListener(new ChildEventListener() {
        @Override
        public void onChildAdded(DataSnapshot dataSnapshot, String s) {
            singleSearchBannerModel = dataSnapshot.getValue(SingleSearchBannerModel.class);

            singleSearchBannerModelList.add(singleSearchBannerModel);
            searchMainAdapter.notifyDataSetChanged();

            System.out.println("this is image in getBanner == "+singleSearchBannerModel.getImage());
        }

        @Override
        public void onChildChanged(DataSnapshot dataSnapshot, String s) {

        }

        @Override
        public void onChildRemoved(DataSnapshot dataSnapshot) {

        }

        @Override
        public void onChildMoved(DataSnapshot dataSnapshot, String s) {

        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });
    return singleSearchBannerModelList;
}

public static List<SingleSearchType1Model> getType1Data(){
    final List<SingleSearchType1Model> singleSearchType1ModelList = new ArrayList<>();
    databaseReference.child("Featured").addChildEventListener(new ChildEventListener() {
        @Override
        public void onChildAdded(DataSnapshot dataSnapshot, String s) {
            singleSearchType1Model = dataSnapshot.getValue(SingleSearchType1Model.class);

            singleSearchType1ModelList.add(singleSearchType1Model);
            searchMainAdapter.notifyDataSetChanged();
        }

        @Override
        public void onChildChanged(DataSnapshot dataSnapshot, String s) {

        }

        @Override
        public void onChildRemoved(DataSnapshot dataSnapshot) {

        }

        @Override
        public void onChildMoved(DataSnapshot dataSnapshot, String s) {

        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });
    return singleSearchType1ModelList;
}

@Override
public void onStart() {
    super.onStart();
    searchMainAdapter = new SearchMainAdapter(getContext(),getObjects());
    System.out.println("this is getObject == "+getObjects());
    System.out.println("this is getBanner == "+getBannerData());
    System.out.println("this is getType1 == "+getType1Data());
    recyclerViewSearch.setAdapter(searchMainAdapter);
}
}

fragment_home.xml 。这是包含一个recyclerview（我的主recyclerview）的片段的xml文件。

<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<android.support.v7.widget.RecyclerView
    android:id="@+id/recyclerview_search"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

</android.support.v7.widget.RecyclerView>

模型文件

*我有两个模型文件。基本上是getter和setter *

SingleSearchBannerModel.java 我的第一个模型文件。

public class SingleSearchBannerModel {

String Image;

public SingleSearchBannerModel() {
}

public SingleSearchBannerModel(String image) {
    Image = image;
}

public String getImage() {
    return Image;
}

public void setImage(String image) {
    Image = image;
}
}

SingleSearchType1Model.java 这是我的第二个模型文件。

public class SingleSearchType1Model {

String Image;

public SingleSearchType1Model() {
}

public SingleSearchType1Model(String image) {
    Image = image;
}

public String getImage() {
    return Image;
}

public void setImage(String image) {
    Image = image;
}
}

RecyclerView适配器

适配器是用于将值设置为recyclerView的适配器。我正在尝试在一个recyclerview中插入两个视图，所以有三个适配器。一个是MainAdapter，它结合了其他两个适配器。 MainAdapter设置为fragment_search.java（我的主要片段）的recyclerview

SearchBannerAdapter.java 。此适配器用于生成所需的布局文件并填充膨胀的布局文件。

public class SearchBannerAdapter extends RecyclerView.Adapter<SearchBannerAdapter.TaskViewHolder>{
List<SingleSearchBannerModel> data;

public SearchBannerAdapter(List<SingleSearchBannerModel> data) {
    this.data = data;
}

@NonNull
@Override
public TaskViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.search_single_banners,parent,false);
    return new TaskViewHolder(view);
}

@Override
public void onBindViewHolder(@NonNull TaskViewHolder holder, int position) {
    SingleSearchBannerModel singleSearchBannerModel = data.get(position);

    Picasso.get().load(singleSearchBannerModel.getImage()).fit().into(holder.imageView);
}

@Override
public int getItemCount() {
    return data.size();
}

public static class TaskViewHolder extends RecyclerView.ViewHolder{
    View mView;
    ImageView imageView;
    public TaskViewHolder(View itemView) {
        super(itemView);
        mView = itemView;
        imageView = mView.findViewById(R.id.search_banner_imgView);
    }
}
}

search_single_banners.xml 在SearchBannerAdapter.java中夸大的xml文件

<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto">

<android.support.v7.widget.CardView
    android:layout_width="290dp"
    android:layout_height="160dp"
    android:id="@+id/longCard"
    android:layout_marginTop="50dp"
    android:layout_marginEnd="20dp"
    app:cardCornerRadius="20sp"
    app:cardElevation="@dimen/ten"
    app:cardPreventCornerOverlap="false"
    android:layout_centerHorizontal="true">

    <ImageView
        android:id="@+id/search_banner_imgView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@drawable/test1"/>

</android.support.v7.widget.CardView>

SearchType1Adapter.java 这是第二个适配器，它使search_type_1.xml夸大

public class SearchType1Adapter extends RecyclerView.Adapter<SearchType1Adapter.TaskViewHolder>{

List<SingleSearchType1Model> data;

public SearchType1Adapter(List<SingleSearchType1Model> data) {
    this.data = data;
}

@NonNull
@Override
public TaskViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.search_type_1,parent,false);
    return new TaskViewHolder(view);
}

@Override
public void onBindViewHolder(@NonNull TaskViewHolder holder, int position) {
    SingleSearchType1Model singleSearchType1Model = data.get(position);

    Picasso.get().load(singleSearchType1Model.getImage()).fit().into(holder.imageView);
}

@Override
public int getItemCount() {
    return data.size();
}

public static class TaskViewHolder extends RecyclerView.ViewHolder{
    View mView;
    ImageView imageView;
    public TaskViewHolder(View itemView) {
        super(itemView);
        mView = itemView;
        imageView = mView.findViewById(R.id.search_single_type_1_imgView);
    }
}
}

search_type_1.xml 在SearchType1Adapter.java中夸大的文件

<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto">

<android.support.v7.widget.CardView
    android:layout_width="290dp"
    android:layout_height="160dp"
    android:id="@+id/longCard"
    android:layout_marginTop="50dp"
    android:layout_marginEnd="20dp"
    app:cardCornerRadius="20sp"
    app:cardElevation="@dimen/ten"
    app:cardPreventCornerOverlap="false"
    android:layout_centerHorizontal="true">

    <ImageView
        android:id="@+id/search_single_type_1_imgView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@drawable/test1"/>

</android.support.v7.widget.CardView>

SearchMainAdapter.java 这是用于fragment_search的主适配器，用于填充主recyclerview。

public class SearchMainAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

private Context context;
private List<Object> items;
private final int BANNER = 1;
private final int TYPE1 = 2;

public SearchMainAdapter(Context context, List<Object> items) {
    this.context = context;
    this.items = items;
}

@NonNull
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    LayoutInflater inflater = LayoutInflater.from(parent.getContext());
    View view;
    RecyclerView.ViewHolder holder;
    switch (viewType){
        case BANNER:
            view = inflater.inflate(R.layout.search_banners,parent,false);
            holder = new BannerViewHolder(view);
            break;
        case TYPE1:
            view = inflater.inflate(R.layout.search_type_1,parent,false);
            holder = new Type1ViewHolder(view);
            break;
        default:
            view = inflater.inflate(R.layout.search_banners,parent,false);
            holder = new Type1ViewHolder(view);
            break;
    }
    return holder;
}

@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
    if(holder.getItemViewType() == BANNER)
        BannerView((BannerViewHolder) holder);
    else if (holder.getItemViewType() == TYPE1)
        Type1View((Type1ViewHolder) holder);
}

private void BannerView(BannerViewHolder holder){
    SearchBannerAdapter searchBannerAdapter = new SearchBannerAdapter(getBannerData());
    holder.recyclerView.setLayoutManager(new LinearLayoutManager(context,LinearLayoutManager.HORIZONTAL,false));
    holder.recyclerView.setAdapter(searchBannerAdapter);
}

private void Type1View(Type1ViewHolder holder){
    SearchType1Adapter searchType1Adapter = new SearchType1Adapter(getType1Data());
    holder.recyclerView.setLayoutManager(new LinearLayoutManager(context,LinearLayoutManager.HORIZONTAL,false));
    holder.recyclerView.setAdapter(searchType1Adapter);
}

@Override
public int getItemCount() {
    return items.size();
}

@Override
public int getItemViewType(int position) {
    if (items.get(position) instanceof SingleSearchBannerModel)
        return BANNER;
    if (items.get(position) instanceof SingleSearchType1Model)
        return TYPE1;
    return -1;
}

public static class BannerViewHolder extends RecyclerView.ViewHolder{
    RecyclerView recyclerView;
    public BannerViewHolder(View itemView) {
        super(itemView);
        recyclerView = itemView.findViewById(R.id.recyclerview_banners);
    }
}
public static class Type1ViewHolder extends RecyclerView.ViewHolder{
    RecyclerView recyclerView;
    public Type1ViewHolder(View itemView) {
        super(itemView);
        recyclerView = itemView.findViewById(R.id.recyclerview_search_type_1);
    }
}
}

search_banners.xml和search_type_1.xml具有相同的代码

<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">

<android.support.v7.widget.RecyclerView
    android:id="@+id/recyclerview_banners"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

</android.support.v7.widget.RecyclerView>

上面的代码不起作用。我想知道我哪里做错了。我的主要目标是制作类似于Google Play商店或hotstar之类的应用程序（就UI而言）。因此，我假设他们正在使用单个recyclerview和其中的多个视图。

感谢帮助。

Answer 1

我知道这个答案有点晚了，但将来可能仍然会对某人有所帮助。这是我实现目标的方式

public class HeteroActivity extends AppCompatActivity {
private ArrayList<Object> objects = new ArrayList<>();
private static final String TAG = HeteroActivity.class.getSimpleName();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_hetero);
    RecyclerView recyclerView = findViewById(R.id.recycler_View);
    MainAdapter adapter = new MainAdapter(this, getObject());
    recyclerView.setAdapter(adapter);
    recyclerView.setLayoutManager(new LinearLayoutManager(this));

}

private ArrayList<Object> getObject() {
    DatabaseReference reference = FirebaseDatabase.getInstance().getReference().child("Data");
    reference.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

            objects.add(getVerticalData(dataSnapshot).get(0));
            objects.add(getHorizontalData(dataSnapshot).get(0));
        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {

        }
    });


    return objects;
}

public static ArrayList<SingleVertical> getVerticalData(DataSnapshot dataSnapshot) {
    ArrayList<SingleVertical> singleVerticals = new ArrayList<>();


    for (DataSnapshot snapshot : dataSnapshot.getChildren()){

        singleVerticals.add(new SingleVertical(

                snapshot.child("price").getValue(String.class),
                snapshot.child("location").getValue(String.class),
                snapshot.child("image").getValue(String.class)

        ));
        Log.e(TAG,"Text loaded");
    }



    return singleVerticals;
}


public static ArrayList<SingleHorizontal> getHorizontalData(DataSnapshot dataSnapshot) {
    ArrayList<SingleHorizontal> singleHorizontals = new ArrayList<>();
    for (DataSnapshot snapshot : dataSnapshot.getChildren()){
        singleHorizontals.add(new SingleHorizontal(

                snapshot.child("price").getValue(String.class),
                snapshot.child("location").getValue(String.class),
                snapshot.child("image").getValue(String.class)
        ));
        Log.e(TAG,"Horizontal data loaded");
    }
    return singleHorizontals;
}

}

然后在主适配器中做到这一点：

private void verticalView(final VerticalViewHolder holder) {
    DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference().child("Data");
    databaseReference.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            VerticalAdapter adapter1 = new VerticalAdapter(getVerticalData(dataSnapshot), context);
            holder.recyclerView.setLayoutManager(new LinearLayoutManager(context));
            holder.recyclerView.setAdapter(adapter1);
        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {

        }
    });


}




private void horizontalView(final HorizontalViewHolder holder) {
    DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference().child("Data");
    databaseReference.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            HorizontalAdapter adapter = new HorizontalAdapter(getHorizontalData(dataSnapshot),context);
            holder.recyclerView.setLayoutManager(new LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false));
            holder.recyclerView.setAdapter(adapter);
        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {

        }
    });
}

使用Firebase实施异构RecyclerView

1 个答案: