从FirebBase数据库中获取数据时，listview中的重复数据

Question

我正在尝试检索根据其ID创建的用户数据。我创建了一个对话框，并在其中创建了一个列表视图，并为其设置了适配器以向他显示swaps（data）。该代码有效，但存在重复列表中数据的问题。因此，如果用户创建了两个拖车交换，那么他会在列表中看到他的拖车交换，并在此之后重复拖曳其他拖车，如果创建了五个，则该交换在列表中会重复五次。简单地说，它就等于存在的交换数量成倍增加。如果您创建了17个，则列表中的17个交换将重复17次。

我不知道是什么原因导致此错误，因为我什至将代码从使用 addChildEventListener 更改为 addListenerForSingleValueEvent 仍然存在。

这是我用来通过数据库节点获取数据的方法。

     私有无效fetchChooseList（）{

    DatabaseReference shiftSwapDb = FirebaseDatabase.getInstance().getReference().child("swaps").child("shift_swaps");

    final List<SwapDetails> swapBodyList = new ArrayList<>();
    Collections.reverse(swapBodyList);
    shiftProfileAdapter = new ShiftProfileAdapter(ProfileActivityShift.this, R.layout.shift_profile_list_item, swapBodyList);
    listView = chooseShiftProfileDialog.findViewById(R.id.listShiftProfileChooseDialog);
    listView.setAdapter(shiftProfileAdapter);

    shiftSwapDb.addChildEventListener(new ChildEventListener() {
        @Override
        public void onChildAdded(DataSnapshot dataSnapshot, String s) {
            if (dataSnapshot.exists()) {
                SwapDetails swapDetails = dataSnapshot.getValue(SwapDetails.class);
                if (swapDetails.getSwapperID().equals(fromID)) {
                    shiftProfileAdapter.add(swapDetails);

                }
            }
        }
        @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) { }
    });


    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
            progressBar_ShiftProfileChooseDialog.setVisibility(View.VISIBLE);
            listView.setVisibility(View.INVISIBLE);
            SwapDetails swapDetails = swapBodyList.get(adapterView.getCount() - i - 1);
            fromLoginID = swapDetails.getSwapperLoginID();
            fromImageUrl = swapDetails.getSwapperImageUrl();
            fromName = swapDetails.getSwapperName();
            fromPhone = swapDetails.getSwapperPhone();
            fromEmail = swapDetails.getSwapperEmail();
            fromCompanyBranch = swapDetails.getSwapperCompanyBranch();
            fromAccount = swapDetails.getSwapperAccount();
            fromShiftDate = swapDetails.getSwapShiftDate();
            fromShiftDay = swapDetails.getSwapperShiftDay();
            fromShiftTime = swapDetails.getSwapperShiftTime();
            fromPreferredShift = swapDetails.getSwapperPreferredShift();
            String child = fromID + fromShiftDay + fromShiftTime + fromPreferredShift + toID + toShiftDay + toShiftTime + toPreferredShift;
            shiftSwapRequestsDb = FirebaseDatabase.getInstance().getReference().child("Swap Requests").child("Shift Request")
                    .child(child);
            swapRequestShift = new SwapRequestShift(toID,
                    toLoginID,
                    toImageUrl,
                    toName,
                    toPhone,
                    toEmail,
                    toCompanyBranch,
                    toAccount,
                    toShiftDate,
                    toShiftDay,
                    toShiftTime,
                    toPreferredShift,
                    fromID,
                    fromLoginID,
                    fromImageUrl,
                    fromName,
                    fromPhone,
                    fromEmail,
                    fromCompanyBranch,
                    fromAccount,
                    fromShiftDate,
                    fromShiftDay,
                    fromShiftTime,
                    fromPreferredShift,
                    -1,
                    -1);
            shiftSwapRequestsDb.setValue(swapRequestShift)
                    .addOnSuccessListener(new OnSuccessListener<Void>() {
                        @Override
                        public void onSuccess(Void aVoid) {
                            //set the request message
                            requestMessage = userName + "" + " wants to swap with your shift";

                            Map<String, Object> notificationMessage = new HashMap<>();
                            notificationMessage.put("message", requestMessage);
                            notificationMessage.put("from", currentUserId);

                            notificationDB.child(swapperID).push()
                                    .setValue(notificationMessage).addOnCompleteListener(new OnCompleteListener<Void>() {
                                @Override
                                public void onComplete(@NonNull Task<Void> task) {
                                    if (task.isSuccessful()) {
                                        progressBar.setVisibility(View.INVISIBLE);
                                    }
                                }
                            }).addOnFailureListener(new OnFailureListener() {
                                @Override
                                public void onFailure(@NonNull Exception e) {
                                    Toast.makeText(ProfileActivityShift.this, "Something went wrong", Toast.LENGTH_LONG).show();
                                    Log.e(LOG_TAG, "Failed to insert row for " + currentUserId);
                                }
                            });
                            Toast.makeText(ProfileActivityShift.this, "Notification sent", Toast.LENGTH_LONG).show();
                            progressBar_ShiftProfileChooseDialog.setVisibility(View.INVISIBLE);
                            listView.setVisibility(View.VISIBLE);
                            chooseShiftProfileDialog.dismiss();
                            shiftProfileDialog.dismiss();
                            progressBar.setVisibility(View.INVISIBLE);
                            textSentOrAcceptedRequest.setVisibility(View.VISIBLE);
                        }
                    }).addOnFailureListener(new OnFailureListener() {
                @Override
                public void onFailure(@NonNull Exception e) {
                    Toast.makeText(ProfileActivityShift.this, e.getMessage(), Toast.LENGTH_LONG).show();
                    progressBar_ShiftProfileChooseDialog.setVisibility(View.INVISIBLE);
                    listView.setVisibility(View.VISIBLE);
                    chooseShiftProfileDialog.dismiss();
                    shiftProfileDialog.dismiss();
                    progressBar.setVisibility(View.INVISIBLE);
                    buttonSwapRequest.setVisibility(View.VISIBLE);
                }
            });
        }
    });

}

我尝试使用addListenerForSingleValueEvent，但结果相同。

  FirebaseDatabase.getInstance().getReference().child("swaps").child("shift_swaps")
            .addListenerForSingleValueEvent(new ValueEventListener() {
                @Override
                public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                    for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                        SwapDetails swapDetails = snapshot.getValue(SwapDetails.class);
                        if (swapDetails.getSwapperID().equals(fromID)) {
                            shiftProfileAdapter.add(swapDetails);
                        }
                    }

                }

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

                }
            });