java - 尝试在将文档接受到集合 Cloud Firestore 之前添加检查

Question

我正在构建一个二维码考勤扫描仪，希望查看扫描是否在我的 session 集合上的开始和结束时间字段的限制内。如果扫描发生在两次之间，则应接受扫描，否则将不接受扫描并显示 toast。目前，我检查 session 是否仅存在，而不是在开始时间和结束时间字段的时间之间存在。 rawData 是从 QR 码中提取的 sessionID，提取后会检查它是否是有效的 sessionID。现在我只需要检查扫描时间。任何帮助都会很棒:

private void barcodeRecognition(Bitmap photo) {
    FirebaseVisionImage image = FirebaseVisionImage.fromBitmap(photo);
    FirebaseVisionBarcodeDetector detector = FirebaseVision.getInstance()
            .getVisionBarcodeDetector();
    Task<List<FirebaseVisionBarcode>> result = detector.detectInImage(image)
            .addOnSuccessListener(new OnSuccessListener<List<FirebaseVisionBarcode>>() {
                @Override
                public void onSuccess(List<FirebaseVisionBarcode> barcodes) {

                    for (FirebaseVisionBarcode barcode: barcodes) {
                        Rect bounds = barcode.getBoundingBox();
                        Point[] corners = barcode.getCornerPoints();

                        final String rawValue = barcode.getRawValue();
                        int valueType =  barcode.getValueType();


                        mAuth.getCurrentUser();
                        // TRY LINKING TO userUID on Attendance on Firebase console
                        FirebaseUser currentUser = mAuth.getCurrentUser();
                        final String user = currentUser.getUid(); // USED TO GET CURRENT USER UID OF PERSON LOGGED IN
                        //THIS CAN BE SET TO .getUserName() or getEmail() depending on preference

                        Calendar calendar = Calendar.getInstance();
                        SimpleDateFormat format = new SimpleDateFormat("HH:mm:ss");
                        final String time = format.format(calendar.getTime());

                        FirebaseFirestore rootRef = FirebaseFirestore.getInstance();
                        DocumentReference docRef = rootRef.collection("Session").document(rawValue);
                        docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
                            @Override
                            public void onComplete(@NonNull Task<DocumentSnapshot> task) {
                                if (task.isSuccessful()){
                                    DocumentSnapshot document = task.getResult();
                                    if (document.exists()){
                                        Attendance attendance = new Attendance(rawValue,user,time);
                                        attendanceRef3.add(attendance);
                                        Toast.makeText(StudentAccount.this, "Your attendance has been recorded", Toast.LENGTH_SHORT).show();
                                    } else {
                                        Toast.makeText(StudentAccount.this, "Session is not available", Toast.LENGTH_SHORT).show();
                                    }
                                }
                            }
                        });

更新的代码

 final FirebaseFirestore rootRef = FirebaseFirestore.getInstance();
                        final DocumentReference docRef = rootRef.collection("Session").document(rawValue);
                        docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
                            @Override
                            public void onComplete(@NonNull Task<DocumentSnapshot> task) {
                                if (task.isSuccessful()){
                                    DocumentSnapshot document = task.getResult();
                                    if (document.exists()){

                                        FirebaseFirestore rootRef = FirebaseFirestore.getInstance();
                                        Query query = rootRef.collection("Session")
                                                .whereGreaterThanOrEqualTo("startTime", calendar.getTime())
                                                .whereLessThan("endTime", calendar.getTime());

                                        Attendance attendance = new Attendance(rawValue,user,time);
                                        attendanceRef3.add(attendance);
                                        Toast.makeText(StudentAccount.this, "Your attendance has been recorded", Toast.LENGTH_SHORT).show();
                                    }
                                    else {
                                        Toast.makeText(StudentAccount.this, "Session is not available", Toast.LENGTH_SHORT).show();
                                    }
                                }
                            }
                        });

编辑代码

 private void barcodeRecognition(Bitmap photo) {
    FirebaseVisionImage image = FirebaseVisionImage.fromBitmap(photo);
    FirebaseVisionBarcodeDetector detector = FirebaseVision.getInstance()
            .getVisionBarcodeDetector();
    Task<List<FirebaseVisionBarcode>> result = detector.detectInImage(image)
            .addOnSuccessListener(new OnSuccessListener<List<FirebaseVisionBarcode>>() {
                @Override
                public void onSuccess(List<FirebaseVisionBarcode> barcodes) {

                    for (FirebaseVisionBarcode barcode: barcodes) {
                        Rect bounds = barcode.getBoundingBox();
                        Point[] corners = barcode.getCornerPoints();

                        final String rawValue = barcode.getRawValue();
                        int valueType =  barcode.getValueType();


                        mAuth.getCurrentUser();
                        // TRY LINKING TO userUID on Attendance on Firebase console
                        FirebaseUser currentUser = mAuth.getCurrentUser();
                        final String user = currentUser.getUid(); // USED TO GET CURRENT USER UID OF PERSON LOGGED IN
                        //THIS CAN BE SET TO .getUserName() or getEmail() depending on preference

                        final Calendar calendar = Calendar.getInstance();
                        SimpleDateFormat format = new SimpleDateFormat("HH:mm:ss");
                        final String time = format.format(calendar.getTime());

                        final FirebaseFirestore rootRef = FirebaseFirestore.getInstance();
                        final DocumentReference docRef = rootRef.collection("Session").document(rawValue);
                        docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
                            @Override
                            public void onComplete(@NonNull Task<DocumentSnapshot> task) {
                                if (task.isSuccessful()){
                                    DocumentSnapshot document = task.getResult();
                                    if (document.exists()) {

                                        Date timeToCheck = calendar.getTime();
                                        Session session = document.toObject(Session.class);
                                        Date startTime = session.getStartTime();
                                        Date endTime = session.getEndTime();
                                        if (timeToCheck.after(startTime) && (timeToCheck.before(endTime))) {

                                            Attendance attendance = new Attendance(rawValue, user, time);
                                            attendanceRef3.add(attendance);
                                            Toast.makeText(StudentAccount.this, "Your attendance has been recorded", Toast.LENGTH_SHORT).show();
                                        }
                                    }
                                    else {
                                        Toast.makeText(StudentAccount.this, "Your attendance attempt is too late", Toast.LENGTH_SHORT).show();
                                    }
                                }
                            }
                        });

Answer 1

根据您的数据库结构，要根据 startTime 和 endTime 属性的限制过滤数据，请使用以下查询:

FirebaseFirestore rootRef = FirebaseFirestore.getInstance();
Query query = rootRef.collection("session")
    .whereGreaterThanOrEqualTo("startTime", timeToCheck)
    .whereLessThanOrEqualTo("endTime", timeToCheck);

如果不想相等，也可以使用下面的代码:

FirebaseFirestore rootRef = FirebaseFirestore.getInstance();
Query query = rootRef.collection("session")
    .whereGreaterThan("startTime", timeToCheck)
    .whereLessThan("endTime", timeToCheck);

因此，使用此代码，您将能够获取 session 集合上开始和结束时间字段限制内的所有 session 对象。

编辑:

如果要检查单个文档，则需要使用另一个 if 语句。因此，在您实际的 if (document.exists()){ 中创建另一个如下所示的代码:

Attendance attendance = document.toObject(Attendance.class);
Date startTime = attendance.getStartTime();
Date endTime = attendance.getEndTime();
if(timeToCheck.after(startTime) && (timeToCheck.before(endTime)) {
    //Do what you need to do
}

其中 timeToCheck 是 Date 类型的对象，您需要根据数据库中的实际日期进行检查。