从firebase查询recyclerView的问题[重复]

Question

目前我面临的问题是，在查询 firebase recyclerView 适配器以对日期进行排序时，该页面中的一切正常，但是当单击特定事件并转到下一页时，某些数据丢失或出现故障，请看在下面的代码中，

EventsRef.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot)
        {
            if (dataSnapshot.exists())
            {
                for (DataSnapshot ds : dataSnapshot.getChildren())
                {
                    String eventId = ds.child("Eid").getValue(String.class);
                    String serveCount = ds.child("Serve").getValue(String.class);

                    list.add(eventId);
                    list3.add(serveCount);

                }

                if (list.size() != 0)
                {
                   RecyclerView();
                }

            }
            else
            {
                progressDialog.dismiss();
                TextView txt = (TextView) findViewById(R.id.txt);
                txt.setVisibility(View.VISIBLE);
            }

        }

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

        }
    });
}


private void RecyclerView()
{
    Query ref = EventsRef.orderByChild("Sort_Date");

    //Display events
    FirebaseRecyclerOptions<WorkerMyEvents> options =
            new FirebaseRecyclerOptions.Builder<WorkerMyEvents>()
                    .setQuery(ref, WorkerMyEvents.class)
                    .build();

    FirebaseRecyclerAdapter<WorkerMyEvents, WorkerMyEventViewHolder> firebaseRecyclerAdapter
            = new FirebaseRecyclerAdapter<WorkerMyEvents, WorkerMyEventViewHolder>(options) {
        @Override
        protected void onBindViewHolder(@NonNull final WorkerMyEventViewHolder eventsViewHolder, int i, @NonNull final WorkerMyEvents newEvents)
        {
            //Id with date and time key
            final String IDs = getRef(i).getKey();
            final String eventIDs = IDs.substring(0,18);

            final String serve = list3.get(i);

            NewEventsRef.child(eventIDs).addListenerForSingleValueEvent(new ValueEventListener() {
                @Override
                public void onDataChange(@NonNull DataSnapshot dataSnapshot)
                {
                    if (dataSnapshot.exists())
                    {
                        //Here will have some data's to display...
                       // I will retrieve Eid from New Events node
                        eventsViewHolder.itemView.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {
                                Intent intent = new Intent(WorkerMyEventActivity.this, WorkerMyEventDetailsActivity.class);
                                intent.putExtra("Eid", Eid);
                                intent.putExtra("sC", serve);
                                startActivity(intent);
                            }
                        });

                        eventsViewHolder.opt_out.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v)
                            {
                                DeletingEvent(IDs, Eid, serve);
                            }
                        });

                        eventsViewHolder.cash_received.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v)
                            {

                            }
                        });

                    }
                    else
                    {
                        progressDialog.dismiss();

                        //notify to the participants...
                        //random key
                        SimpleDateFormat formatter = new SimpleDateFormat("ddMMYYYY");
                        Date date = new Date();
                        String tdyDate = formatter.format(date);

                        Calendar calendar = Calendar.getInstance();
                        SimpleDateFormat currentTime = new SimpleDateFormat("HHmma");
                        String saveCurrentTime = currentTime.format(calendar.getTime());

                        String randomkey = tdyDate + saveCurrentTime;
                        //random key


                        String Notify = "The event you participated has been deleted by contractor";
                        HashMap<String,Object> map = new HashMap<>();
                        map.put("message", eventIDs + " - " + Notify);
                        workerRef.child("Notifications").child(randomkey).updateChildren(map);
                        workerRef.child("Notifications").child("current_counts").child(randomkey).updateChildren(map);

                        //remove Live event event id's from database...
                        EventsRef.child(eventIDs).removeValue();
                        TextView txt = (TextView) findViewById(R.id.txt);
                        txt.setVisibility(View.VISIBLE);
                    }
                }

                @Override
                public void onCancelled(@NonNull DatabaseError databaseError)
                {
                    progressDialog.dismiss();
                }
            });

        }

        @NonNull
        @Override
        public WorkerMyEventViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType)
        {
            View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.worker_my_event_layout, parent, false);
            WorkerMyEventViewHolder holder = new WorkerMyEventViewHolder(view);
            return holder;
        }
    };
    recyclerView.setAdapter(firebaseRecyclerAdapter);
    firebaseRecyclerAdapter.startListening();

这是我的代码在当前活动中一切正常。但是在执行此操作时 [ Query ref = EventsRef.orderByChild("Sort_Date"); ] 一些数据或参考问题出现在下一页。

下一个活动（）； //我面临问题的代码

ref3Male.child(userID).addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot)
        {
            if (dataSnapshot.exists())
            {
                //This needs to come ,if that query is not applied in the previous activity this works fine. but while using that it is not working, its movingto else part.
            }
            else{

            }
        }

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

        }
    });

实际上，在上面的代码中，如果查询未在以前的活动中应用，则 dataSnapShot 将存在，但是在使用它时它会转到其他部分，请指导我在哪里做错了朋友。提前致谢。

通过使用上述数据库结构，我将通过对日期进行排序来获取键，并通过使用键，我将从该数据库结构下面的节点获取详细信息，（我只发布了一个节点结构，但它会有很多）

第二个图像参考是我在下一个活动（）中使用的..

现在我也注意到并使用时间戳将该日期类型从字符串更改为长类型，但仍然存在这个问题......

我还研究了一些东西，并注意到在活动 1 中将在回收站视图中有项目列表，因为只有第一个和第二个事件只有这个问题，其余的工作正常，当我点击那个事件时，这些细节在下一页查看。

现在我注意到活动 1 中有另一件事，对于第一个两个项目，参考不起作用（参考 - 在第一张图像中），其余的工作正常。

public class WorkerMyEvents
{
private String Eid;

public WorkerMyEvents() {
}

public WorkerMyEvents(//Here also) {
   //Constructors
}

//Getters and setters

}

Answer 1

我认为您传递的EventID 不正确，请在点击后执行此操作：

eventsViewHolder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(WorkerMyEventActivity.this, WorkerMyEventDetailsActivity.class);

//pass the event ID
intent.putExtra("Eid", newEvents.getEid());

//pass other stuff if needed.......

startActivity(intent);
}
});

在WorkerMyEventDetailsActivity的onCreate()方法中：

//in onCreate()

String eventID = getIntent().getStringExtra("Eid");


//when you want to read the ref

DatabaseReference ref = FirebaseDatabase.getInstance().getReference().child("New Events");


//read data

ref.child(eventID).addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot)
        {
            if (dataSnapshot.exists())
            {
            //this should trigger and then you can get details.......
            }
            else{

            }
        }

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

        }
    });