如何将firebase数据加载到recyclerview中-Java 学习之路

我正在寻求有关如何将存储在Firebase数据库中的数据加载到 recyclerview 的帮助 .

下面的屏幕截图显示了加载到 recyclerview 时我希望如何构建数据 .

我可以使用 addEventListener 访问来自各个路径的数据，例如"Upcoming/Events/03/23"，但无法以上述格式动态加载到 recyclerview .

请参阅下面的代码我在下面加载不同节点下的子项，但我可以将其加载到 recyclerview

private ListView mUserList;
private ArrayList<String> mUpcomingList = new ArrayList<>();

final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_expandable_list_item_1,mUpcomingList);
mUserList.setAdapter(arrayAdapter);

String CurrentString = date.toString().trim();
StringTokenizer tokens = new StringTokenizer(CurrentString, "/");
String first = tokens.nextToken();
String second = tokens.nextToken();
mDatabase = FirebaseDatabase.getInstance().getReference().child("Upcoming/Events").child(first);
mDatabase.addValueEventListener(new ValueEventListener() {

@Override
Public void onDataChange(DataSnapshot dataSnapshot) {

Log.d(TAG,"Listing children");

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


mUpcomingList.add(child.getKey());
arrayAdapter.notifyDataSetChanged();
}

感谢您的帮助 .

2 回答

你必须使用 FirebaseRecyclerAdapter ，as

FirebaseRecyclerAdapter<Model, ViewHolder> Adapter = new FirebaseRecyclerAdapter<Model, ViewHolder>(
            Model.class,  //Name of model class
            R.layout.row, //Row layout to show data
            viewHolder.class, //Name of viewholder class
            mDatabaseRef // Database Refernce
    ) {
        @Override
        protected void populateViewHolder(VieHolder viewHolder, Model model, int position) {

//Your Method to load Data

      }
    };
 RecyclerView.setAdapter(Adapter);

为此，您必须创建另外两个类，一个是视图持有者（显示数据），另一个是模型类（指的是从中获取数据的节点的名称） .

回复于 2024-05-02T04:16:22+08:00

当您使用时，您可以创建recyclerview adatper并将此适配器绑定到Recycler视图中 . 使用下面的代码显示firebase的所有数据，并根据您的需要进行更改并进行更改 .

RecyclerView适配器::

public class DisplayAllData extends RecyclerView.Adapter<DisplayAllData.ItemViewHolder>{
private  List<User> mUserLsit=new ArrayList<>();
private Context mContext;

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

public DisplayAllData(Context mContext,List<User> mUserLsit) {
    this.mContext=mContext;
    this.mUserLsit = mUserLsit;
}

@Override
public void onBindViewHolder(ItemViewHolder holder, int position) {
    User user=mUserLsit.get(position);
    holder.mTvName.setText(user.name);
    holder.mTvEmail.setText(user.email);
    holder.mTvPwd.setText(user.pwd);
}

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

public class ItemViewHolder extends RecyclerView.ViewHolder {
    TextView mTvName,mTvEmail,mTvPwd;
    public ItemViewHolder(View itemView) {
        super(itemView);
        mTvEmail=itemView.findViewById(R.id.rlTvEmail);
        mTvName=itemView.findViewById(R.id.rlTvName);
        mTvPwd=itemView.findViewById(R.id.rlTvPwd);

    }
}

}

在适配器中采用简单的布局，并进行三个textview控件并将数据绑定到其中 . 然后采取活动布局并在xml中定义回收站视图 . 然后使用下面的代码来读取firebase数据库记录并显示recyclerview .

public class DisplayActivity extends AppCompatActivity {
private RecyclerView mRvData;
private DisplayAllData allDataAdapter;
private DatabaseReference mDatabase;
private TextView mTvEmpty;
private FirebaseDatabase mFirebaseInstance;
private List<User> mUserList = new ArrayList<>();

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.display_data);
    initView();
}

private void initView() {
    mFirebaseInstance = FirebaseDatabase.getInstance();
    mDatabase = mFirebaseInstance.getReference("usersDb/UserTable");
    mRvData = findViewById(R.id.rvData);
    mTvEmpty = findViewById(R.id.dlTvEmpty);
    mRvData.setLayoutManager(new LinearLayoutManager(this));
    mDatabase.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            mUserList.clear();
            for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                User user = dataSnapshot1.getValue(User.class);
                mUserList.add(user);
            }
            allDataAdapter = new DisplayAllData(DisplayActivity.this, mUserList);
            mRvData.setAdapter(allDataAdapter);
            allDataAdapter.notifyDataSetChanged();
            if (mUserList.isEmpty())
                mTvEmpty.setVisibility(View.VISIBLE);
            else
                mTvEmpty.setVisibility(View.GONE);
        }


        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });
}

}

回复于 2024-05-02T04:16:22+08:00

如何将firebase数据加载到recyclerview中

2 回答

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