Question

我是Android开发的新手，需要帮助将Firebase Realtime数据库中的数据填充到FirebaseRecyclerAdapter中。

我的应用程序包含一个研讨会列表。用户可以使用GitHub身份验证登录到我的测试应用程序，如果按下了相关按钮，我会收到用户电子邮件以登录或注销研讨会。

因此，在某些情况下，我的工作室包含Firebase中以下示例的用户列表。

问题是我需要在回收者视图中突出显示用户已经登录的研讨会。

我遇到的主要问题是在填充每个研讨会的信息时。以后我可以轻松地让用户分别列出，但是从一开始我就不知道如何在一个不错的Workshop对象中做到这一点。

我迷路了。请帮忙。

我的FirebaseRecyclerAdapter：

public class WorkshopsFirebaseRecyclerAdapter extends FirebaseRecyclerAdapter<Workshop, WorkshopViewHolder> {

    private Context mContext;
    private ProgressBar progressBar;

    public WorkshopsFirebaseRecyclerAdapter(FirebaseRecyclerOptions<Workshop> options, Context context, ProgressBar view) {
        super(options);
        mContext = context;
        progressBar = view;
    }

    @Override
    public void onDataChanged() {
        if (progressBar != null) {
            progressBar.setVisibility(View.GONE);
        }
    }

    @Override
    protected void onBindViewHolder(@NonNull final WorkshopViewHolder holder, final int position, @NonNull final Workshop model) {

        final Workshop workshop = getItem(position);
        final String id = getRef(position).getKey();

        holder.date.setText(getUserFriendlyDate(workshop.getDate()));
        holder.description.setText(workshop.getDescription());

        if (workshop.getWorkshopAttendants() != null){
            Timber.i("onBindViewHolder workshop is %s", workshop.toString());
        }

        holder.getView().setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                TinyDB tinyDB = new TinyDB(mContext);
                tinyDB.putObject(mContext.getString(R.string.workshop_tinydb_key), workshop);
                Intent intent = new Intent(mContext, WorkshopDetailsActivity.class);
                intent.putExtra(mContext.getString(R.string.open_workshop_details_intent_key),
                        WorkshopDetailsActivity.INTENT_OPEN_UPDATE_WORKSHOP_DETAILS);
                intent.putExtra(mContext.getString(R.string.current_workshop_id_key), id);
                mContext.startActivity(intent);
            }
        });
    }

    @Override
    public WorkshopViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View itemView = LayoutInflater.from(viewGroup.getContext())
                .inflate(R.layout.workshop_rv_item, viewGroup, false);
        return new WorkshopViewHolder(itemView);
    }

    private String getUserFriendlyDate(String dateOld){
        Date date = new Date();
        SimpleDateFormat oldDateFormat = new SimpleDateFormat("dd-MM-yyyy", Locale.UK);
        try {
            date = oldDateFormat.parse(dateOld);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        SimpleDateFormat newDateFormat = new SimpleDateFormat("dd MMM yyyy", Locale.UK);
        return newDateFormat.format(date);
    }

}

设置适配器和查询的方法：

 private void loadWorkshopsForCity(String city) {
        Query query;
        if (city.equals(getString(R.string.spinner_cities_all_value))) {
            query = FirebaseDatabase.getInstance()
                    .getReference(getString(R.string.firebase_root_name))
                    .child(getString(R.string.firebase_workshops_root_name))
                    .limitToLast(50);
        } else {
            query = FirebaseDatabase.getInstance()
                    .getReference(getString(R.string.firebase_root_name))
                    .child(getString(R.string.firebase_workshops_root_name))
                    .orderByChild(getString(R.string.firebase_workshop_city_name_key))
                    .equalTo(city);
        }

        query.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                for (DataSnapshot workshopSnapshot : dataSnapshot.getChildren()) {
                    Workshop workshop = workshopSnapshot.getValue(Workshop.class);
                    for(DataSnapshot usersSnapshot : workshopSnapshot.child("users").getChildren()){
                        if (usersSnapshot.exists()){
                            WorkshopAttendant user = usersSnapshot.getValue(WorkshopAttendant.class);
                            if (user!=null){
                                users.add(user);
                            }
                        }
                    }
                    if (users.size()!=0){
                        workshop.setWorkshopAttendants(users);
                    }
                }
            }


            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
                Timber.i(databaseError.toException());
            }
        });

        FirebaseRecyclerOptions<Workshop> options =
                new FirebaseRecyclerOptions.Builder<Workshop>()
                        .setQuery(query, Workshop.class)
                        .build();

        if (adapter != null) {
            adapter.stopListening();
        }

        adapter = new WorkshopsFirebaseRecyclerAdapter(options, this, progressBar);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
        mRecyclerView.setAdapter(adapter);
        adapter.startListening();

    }

我的包含与会者列表的工作坊：

public class Workshop {

    private String date;
    private String time;
    private String description;
    private String name;
    private String address;
    private String city;
    private List<WorkshopAttendant> workshopAttendants;

    private boolean isChecked;

    // empty constructor for firebase
    public Workshop() {
    }

    public Workshop(String date, String time, String description, String name, String address, String city,
                    List<WorkshopAttendant> workshopAttendants) {
        this.date = date;
        this.time = time;
        this.description = description;
        this.name = name;
        this.address = address;
        this.city = city;
        this.workshopAttendants = workshopAttendants;
    } .....

和其他应该在Workshop对象内部的WorkshopAttendant。

public class WorkshopAttendant {

    private String email;
    private int role; // 1 - coach ; 0 - organiser ; 2 - student

    public WorkshopAttendant(String userEmail, int role) {
        this.email = userEmail;
        this.role = role;
    }

    // for firebase
    public WorkshopAttendant() {
    }

Answer 1

1）将Workshop模型中的Workshop参与者列出到Map用户= new HashMap <>（）;

2）为我的Recycler选项使用了新的SnapshotParser；

FirebaseRecyclerOptions<Workshop> options =
                new FirebaseRecyclerOptions.Builder<Workshop>()
                        .setQuery(query, new SnapshotParser<Workshop>() {
                            @NonNull
                            @Override
                            public Workshop parseSnapshot(@NonNull DataSnapshot snapshot) {
                                GenericTypeIndicator<Workshop> t = new GenericTypeIndicator<Workshop>() {};
                                Workshop workshop = snapshot.getValue(t);
                                return workshop;
                            }
                        })
                .build();

3）我在适配器中设置了用户检查功能，因此现在可以标记有用户签名的研讨会。

try {
            Map<String, User> users = workshop.getValue();
            if (users.size()!=0){holder.description.setBackgroundColor(mContext.getColor(R.color.colorPrimaryDark));
            }
        } catch (NullPointerException e){
            Timber.i(e, "no users for %s", workshop.getDescription());
        }

感谢@AlexMamo的耐心

FirebaseRecyclerAdapter用内部的其他对象填充对象

1 个答案: