How to get variable from the asynchronous call back?

General
1

Hello,

I’m developing an android app and I want to make a logic layer for the queries of the database.
I have the following code:

Backendless.Persistence.of(Unit.class).find(dataQueryUnit, new AsyncCallback<BackendlessCollection<Unit>>() {
@Override
public void handleResponse(BackendlessCollection<Unit> unitBackendlessCollection) {
BackendlessCollection<Unit> resultUnits = unitBackendlessCollection;
List<Unit> unitList = resultUnits.getData();
int numberOfUnits = unitList.size();
}
@Override
public void handleFault(BackendlessFault backendlessFault) {
// Toast.makeText(SelectUnit.this, “error”, Toast.LENGTH_SHORT).show();
}
});

I want to make a function that returns the numberOfUnit variable. The problem is that I can’t access that variable.

2

I tried using a “final” variable but it didn’t work.

3

Hi Miriam,
You need to move the unit of work you need perform after request to handleResponse method.
In computer programming such paradigm is called Callback. Read more at https://en.wikipedia.org/wiki/Callback_(computer_programming).
Best wishes, Artur