for loop not running inside single value event listener

I'm trying to implement a search feature where, upon clicking on the search result, I display the user's details in a fragment. The problem is in the init() function where the foreach loop inside the onDataChange() funcion doesn't execute.

private User mUser;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_view_profile, container, false);
try{
mUser = getUserFromBundle();
init();
}catch (NullPointerException e){
Log.e(TAG, "onCreateView: NullPointerException: "  + e.getMessage() );
setupFirebaseAuth();
return view;
}
private void init(){
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference.child(getString(R.string.db_user_account_settings)).orderByChild(getString(R.string.field_user_id)).equalTo(mUser.getUserid());
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot :  dataSnapshot.getChildren()){
UserSettings settings = new UserSettings();
settings.setUser(mUser);
settings.setSettings(singleSnapshot.getValue(UserAccountSettings.class));
setProfileWidgets(settings);
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
throw databaseError.toException();
}
});
}
private User getUserFromBundle(){
Bundle bundle = this.getArguments();
if(bundle != null){
return bundle.getParcelable(getString(R.string.intent_user));
}else{
return null;
}
}

strings.xml

<resources>
<string name="field_user_id">user_id</string>    
<string name="intent_user">intent_user</string>    
<string name="db_user_account_settings">user_account_settings</string>  
</resources  

I have no idea why this isn't working.

From comment:

> 1), 2) I've added the strings.xml code you can refer to 3) The blue arrow in the screenshot shows the userid that is returned (which is exactly what I want) 4) The red portion is what I'm querying 5) Yes. I'm a bit new with JSON and firebase,

Your code does:

reference.child(getString(R.string.db_user_account_settings)).orderByChild(getString(R.string.field_user_id)).equalTo(mUser.getUserid())

Which translates to:

reference.child("user_account_settings").orderByChild("user_id").equalTo(mUser.getUserid())

So it:

1. Takes all child nodes under user_account_settings.
2. Orders them on the value of their user_id property.
3. Selects only the nodes where that value exists and is equal to the UID.

Since the JSON you showed doesn't show a user_id property, there are no results.

If you have the value you are looking for as the key of a node, you can just use child(...) to look that node up. And since there can only be one child node with a given key, that means you no longer need the loop over getChildren() in the onDataChange method.

So something like:

DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference.child(getString(R.string.db_user_account_settings)).child(mUser.getUserid());
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
UserSettings settings = new UserSettings();
settings.setUser(mUser);
settings.setSettings(singleSnapshot.getValue(UserAccountSettings.class));
setProfileWidgets(settings);
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
throw databaseError.toException();
}
});