Do not showing the Spinner Selected item.

[Tarikul711]

I tried but I can't show the spinner selected item in the list.

[msbcs]

It's because the setup of the spinner needs to be done inside a successful or completed task for example :-

collectionRef.get().addOnCompleteListener(task -> {
                if (task.isSuccessful()) {
                    for (QueryDocumentSnapshot document : task.getResult()) {
                        //Log.d(TAG, document.getId() + " => " + document.getData().get("myField")); // replace 'myField' with your field name
                        categories.add((String) document.getData().get("name"));
                    }
                    //Spinner setup inside the successful task
                    ArrayAdapter<CharSequence> adapter = new
                            ArrayAdapter<CharSequence>(this, android.R.layout.simple_spinner_item, categories);
                    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                    //mySpinner.setSelection(0);
                    mySpinner.setAdapter(adapter);
                } else {
                    Log.d(TAG, "Error getting documents: ", task.getException());
                }
            });