如何修复时间戳 java + firestore 问题？

Question

我正在创建一个基于 firestore 和 java android 的聊天应用程序 ,根据https://firebase.google.com/docs/reference/android/com/google/firebase/Timestamp按时间戳对聊天进行排序

但是排序是每次都取决于设备时间，即使设备上的时间是错误的，这让我很失望，请帮忙！！

---

我的上传时间戳代码：

Timestamp dd= Timestamp.now();
long tt=dd.getSeconds();
        hashMap.put("ServerTimes",tt);

我的下载时间戳代码：

@Override
    public void onBindViewHolder(@NonNull final MessageAdapter.ViewHolder holder, int position) {

Chat chat = mChat.get(position);
       long date = (long) chat.getServerTimes();

        Date date3 = new Date ();
        date3.setTime(date*1000);


        SimpleDateFormat format1 = new SimpleDateFormat("dd/MM/yyyy EEE");
        SimpleDateFormat format2 = new SimpleDateFormat("h:mm:s a");

        String dateDisplay1 = format1.format(date3);
        String dateDisplay2 = format2.format(date3);
String DateTime= dateDisplay1+" -- "+dateDisplay2;

我的排序代码：

  private void readMessages(final String myEmail, final String OtherUserEmail, final String imageUrl) {
            final List<Chat> mChat = new ArrayList<>();
    referenceContent.orderBy("ServerTimes", Query.Direction.ASCENDING) .addSnapshotListener(new EventListener<QuerySnapshot>() {
                @Override
                public void onEvent(@Nullable QuerySnapshot queryDocumentSnapshots, @Nullable FirebaseFirestoreException e) {
................

Answer 1

如果您不想依赖客户端时间戳，可以将 Firestore 告知 write a server-side timestamp。从该文档链接：

// Update the timestamp field with the value from the server
Map<String,Object> updates = new HashMap<>();
updates.put("timestamp", FieldValue.serverTimestamp());

docRef.update(updates).addOnCompleteListener(new OnCompleteListener<Void>() {
  ...