Set varable according to what another variable says

This is hard to explain so here it is with code:

int theVariable;
setVariable(theVariable, 10);

void setVariable(variableName, variableContents){
  variableName.setValue(variableContents);
}

I am making a library for settings and when I call addTextField() I want to be able to pass a variable name so when you change the text field, that variable is auto-set. I was thinking reflection, but I am not sure if that is the way to go.