Is there a way to write this database call into a function easily?

Question

All of the text in an application I'm working on is stored inside FireStore documents, so to retrieve it I use this bit of code

db.collection("language").document("kCreateNewAccount").get()
  .addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
      @Override
      public void onSuccess(DocumentSnapshot documentSnapshot) {
           String viewText = lan.equals("en") ? documentSnapshot.getString("en")
                                              : documentSnapshot.getString("es");
           createAccount.setText(viewText);
      }
  });

I've tried to put it into a function that takes the document name as a parameter and returns the correspondent string to avoid writing the same thing over and over again, to no avail, any help is welcome

Firestore queries are asynchronous. You won't be able to simply wrap it into a function that directly returns the result. The wrapper function will itself have to be asynchronous and accept a callback function like Firestore query. (Otherwise you would block the calling thread, which is almost always bad idea on Android.) — Doug Stevenson, Jun 20 '20 at 06:23

score 1 · Accepted Answer · edited Jun 20 '20 at 13:56

Firebase queries are async, you have to use a callback function.

Create Interface for callback

 public interface OnCompleteListener {
     void onComplete(String text);
 }

Create method for fetching text via document name

 public void getText(String document, final OnCompleteListener onCompleteListener) {
         db.collection("language").document(document).get()
                 .addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
                     @Override
                     public void onSuccess(DocumentSnapshot documentSnapshot) {
                         String viewText = lan.equals("en") ? documentSnapshot.getString("en")
                                 : documentSnapshot.getString("es");
                         onCompleteListener.onComplete(viewText);
                     }
                 });
     }

Call the method with your document name and specifying a listener

 getText("kCreateNewAccount", new OnCompleteListener() {
             @Override
             public void onComplete(String text) {
                 createAccount.setText(text);
             }
         });

Is there a way to write this database call into a function easily?

1 Answers1

Linked