"Values to set on static text box on push button not working in Matlab

Question

I am trying to show variable value to static text box on push button click, but it's not working.

I set the tag of text box to "db". I tried

set(handles.db,'String',simIndex);

by Assign a value to a static text in GUI MATLAB

also tried

set(findobj('Tag','db'),'String',simIndex)); 

but nothing seems to work.

I am adding more stuff. i am trying to compare variables return by two separate functions and to display the computed score to static text box that's all happening on push button click.

function pushbutton2_Callback(hObject, eventdata, handles)
[FileName,FilePath]=uigetfile('C:\Users\Usman Anwer\Documents\MATLAB  \AudioFiles\training_files\*.wav','Select a speaker file to test');
s1=VoiceFraming(FileName,FilePath);
newSpeaker=GMMCollect(s1');
w=loadSpeaker();
%global simIndex;
simIndex=SimIndex(newSpeaker,w.x)
%fig = openfig('Project_Fine.fig');
%handles = guihandles(fig);
str=num2str(simIndex);
set(handles.sim,'String','1');
%guidata(hObject, handles);