对Firebase Firestore Android中的数据执行加法/操作

FirebaseFirestore db = FirebaseFirestore.getInstance();
DocumentReference docRef = db.collection("collectionName").document("documentId");

db.runTransaction(new Transaction.Function<Void>() {
    @Nullable
    @Override
    public Void apply(@NonNull Transaction transaction) throws FirebaseFirestoreException {
        DocumentSnapshot snapshot = transaction.get(docRef);
        if (snapshot.exists()) {
            long currentValue = snapshot.getLong("fieldName");
            long newValue = currentValue + 1; // 这里执行加法操作，可以根据需求修改
            transaction.update(docRef, "fieldName", newValue);
        }
        return null;
    }
}).addOnSuccessListener(new OnSuccessListener<Void>() {
    @Override
    public void onSuccess(Void aVoid) {
        // 加法操作成功
    }
}).addOnFailureListener(new OnFailureListener() {
    @Override
    public void onFailure(@NonNull Exception e) {
        // 加法操作失败
    }
});