How to use psychtoolbox with matlab gui?

1
I wrote a script to show the coordinate of cursor in a matlab gui text box.It should update realtime but it only update when I double click the GUI figure.Any one can help me?Thanks in advance.

Here is the code:

function polarposition
global data;
%h1=uicontrol('style', 'text', 'string', 'mouse position', 'position', [10 10 150 50]);
h1=uicontrol('style', 'text', 'position', [10 10 150 50]);
h2=uicontrol('style', 'pushbutton', 'string', 'start polar grating', ...
'position', [10 70 150 50], 'callback',@polargrating,'interruptible','on');
data.position=h1;
end

function polargrating(hObject, eventdata)

ifis=1;
numFrames=60;%both ifis and numFrames determine the temperal frequency
wc=0.04*2*pi;
wr=8;
try
global data;
AssertOpenGL;
screens=Screen('Screens');
screenNumber=max(screens);
w=Screen('OpenWindow',screenNumber);
[width, height]=Screen('WindowSize', w);
Screen('BlendFunction', w, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

white=WhiteIndex(screenNumber);
black=BlackIndex(screenNumber);
gray=(white+black)/2;
if round(gray)==white
gray=black;
end
inc=white-gray;

s=min(width, height) ./ [4 4];
[x1,y1]=meshgrid(0:s(1)/2, -s(2)/2:s(2)/2);
[x2,y2]=meshgrid(-s(1)/2:-1, -s(2)/2:s(2)/2);

for i=1:numFrames
phase=(i/numFrames)*2*pi;
%m=sin(wc*sqrt(x.*x+y.*y)+wr*atan(y./x)+phase);
m1=sin(wc*sqrt(x1.*x1+y1.*y1)+wr*asin(y1./sqrt(x1.*x1+y1.*y1))+phase);
m2=sin(wc*sqrt(x2.*x2+y2.*y2)+wr*(pi-asin(y2./sqrt(x2.*x2+y2.*y2)))+phase);
m=[m2,m1];
gratingtex=(gray+inc*m);
tex(i)=Screen('MakeTexture', w, gratingtex);
end
tavg=0;

ifi_duration = Screen('GetFlipInterval', w);
movieDurationSecs=500; %stimulus duration

frameRate=Screen('FrameRate',screenNumber);
if(frameRate==0) % if MacOSX does not know the frame rate the 'FrameRate' will return 0.
frameRate=60; % 60 Hz is a good guess for flat-panels...
end

movieDurationFrames=round(movieDurationSecs * frameRate / ifis);
movieFrameIndices=mod(0:(movieDurationFrames-1), numFrames) + 1;

priorityLevel=MaxPriority(w);
Priority(priorityLevel);

Screen('FillRect',w, gray);
vbl = Screen('Flip', w);
% hidecursor;

for i=1:movieDurationFrames
t1=GetSecs;
mxold=0;
myold=0;

WaitSecs(0.01);
[mx, my, buttons]=GetMouse(screenNumber);
myrect=[mx-s(1)/2 my-s(2)/2 mx+s(1)/2-1 my+s(2)/2-1];

Screen('DrawTexture', w, tex(movieFrameIndices(i)),[],myrect);
vbl=Screen('Flip', w, vbl + (ifis - 0.5) * ifi_duration);
mxold=mx;
myold=my;

xstr=num2str(mxold);
ystr=num2str(myold);
coordinate=[xstr,' ',ystr];
set(data.position,'string',coordinate);

[keyIsDown, secs, keyCode] = KbCheck;
if KbName(keyCode)=='q'
break;
end;

t1=GetSecs - t1;
if (i>numFrames)
tavg=tavg+t1;
end;

end;

Priority(0);

tavg=tavg / (movieDurationFrames - numFrames)

% We're done: Close all windows and textures:
Screen('CloseAll');
catch
Priority(0);
Screen('CloseAll');
psychrethrow(psychlasterror);
end
end