Firebase Firestore 无法读取所有数据（Android）

Question

我一直在尝试从我的 Firestore 云数据库中读取数据，但我无法做到！

这是我的数据库：

这是我的代码：

CollectionReference collectionReference = mFirestore.collection("Users");
collectionReference.whereEqualTo("Mobile", mobile.getText().toString()).get().addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
    @Override
    public void onSuccess(QuerySnapshot queryDocumentSnapshots) {
        mobile.setText("");
        Toast.makeText(sign_up_page.this, "Mobile Number Already In Use!", Toast.LENGTH_SHORT).show();
    }
});

Answer 1

您似乎是在告诉collectionReference 在文档部分的Users 之后找到.whereEqualTo Mobile。

相反，您可以尝试：

DocumentReference docRef = db.collection("Users").document("XSPH..."); // fill with the whole item which starts by `XSPH`
docRef.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
       @Override
       public void onSuccess(DocumentSnapshot documentSnapshot) {

          String mobileItem = documentSnapshot.get("Mobile"); // Declare it as string or integer or whatever you want in here

          Log.d("TAG", documentSnapshot.getString("Mobile")); // or try this
          // Print the mobileItem 

            ...
            ..

看看：https://firebase.google.com/docs/firestore/query-data/get-data#get_a_document