To check if id1 is present inside the uIds array in a really simpler manner, first, you should create a class:
class Document {
List<String> uIds;
}
Then get the "AUScbTj5MpNY.." document and read the content of the uIds array using the following method:
private void checkId(String id) {
String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
FirebaseFirestore rootRef = FirebaseFirestore.getInstance();
CollectionReference followingRef = rootRef.collection("Following");
DocumentReference uidRef = followingRef.document(uid);
uidRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
if (task.isSuccessful()) {
DocumentSnapshot document = task.getResult();
if (document.exists()) {
List<String> uIds = document.toObject(Document.class).uIds;
if (uIds.contains(id)) {
//Update the UI
}
} else {
Log.d(TAG, "No such document");
}
} else {
Log.d(TAG, "get failed with ", task.getException());
}
}
});
}
Inside the onComplete, we get the array as a List and check if the id with which we are calling the method, exists inside the array. To make it work, kick it off with:
checkId(id1);
Please also note that:
firebaseFirestore.collection("Following)
.document(FirebaseAuth.getInstance().getCurrentUser().getUid())
.collection("uIds").where(/* ... /*);
Will never work, as uIds is an array inside a document and not a collection.
You can also find more info, in the following article:
