在將文檔接受到集合Cloud Firestore中之前嘗試添加支票

Question

我正在構建一個qr出勤掃描儀，希望查看掃描是否在我的session集合的start時間和end時間字段的范圍內。 如果掃描在兩次之間進行，則應接受，否則將不接受，並顯示祝酒詞。 目前，我正在檢查會話是否僅存在，而在開始時間和結束時間字段之間不存在。 rawData是從QR碼中提取的sessionID ，提取后將檢查其是否為有效的sessionID。 現在，我只需要檢查掃描時間。 任何幫助都會很棒：

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();
                                    }
                                }
                            }
                        });

更新的代碼

 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();
                                    }
                                }
                            }
                        });

編輯代碼

 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

根據您的數據庫結構，要根據startTime和endTime屬性的限制過濾數據，請使用以下查詢：

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

如果不想相等，還可以使用以下代碼：

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

因此，使用此代碼，您將可以獲得在會話集合的開始時間和結束時間字段范圍內的所有session對象。

編輯：

如果要檢查單個文檔，則需要使用另一個if語句。 因此，在您的實際if (document.exists()){創建另一個如下所示的代碼：

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類型的對象，您需要根據數據庫中的實際日期進行檢查。