waitfor UIbutton press? HELP!

HI! i need some help with this issue, mi code is a drawnow loop, so i want to make a uibutton to pause the loop, and then press it again and unpause.

function pushbutton6_Callback(hObject, eventdata, handles)

f = warndlg('This is a warning.', 'A Warning Dialog'); waitfor(f);

this code work, but is not exactly what i need,(this opens a dialog with a button) is there a way to change this function to work? THANKS A LOT! (the command has to be waitfot, because its a simulation and pause dont work)