Static text not showing the whole string when loaded with set(handles.text3, 'String', myString)

Question

I am using a customer GUI made with GUIDE in conjunction with an arduino and a bluetooth module. Long story short is that I want to be able to read/write over bluetooth to an SD card. This all works fine!

But! When reading back from the sd card, matlab reads the correct data. I can verify this because when printing to the command window it shows the correct data that was on the sd card.

The problem is that when i try set this data to the string of a static text in guide some funny things happen. The static text can be loaded with text, but if i then add more text to the file it's loading from and try to read it out again it still only displays the old data. I know that the string is being updated because as I said when I print to the command it shows the right data.

I have had strange problems with setting static text with this project, Anyone have any ideas to make it easier? Other problems I have had are setting the string in the beginning of a callback function but the text not actually being updated until after the callback has executed the whole function or thrown an error or whatnot.

Answer 1

Problem was no drawnow so matlab didn't draw until the whole function was finished.

Answer 2

Is the string too long for the string GUI element, e.g., the string GUI element can only hold 5 lines, and you're trying to display 6, then 7, etc. ?

Matlab does not automatically produce scroll bars on static text. See http://www.mathworks.com/matlabcentral/newsreader/view_thread/148773 for a discussion of alternatives. What I do (courtesy of a co-worker showing me this) on real-time log displays is (assuming this is in a loop) this, with TxtMssg being my text "box" and rec_line being the line I read from the serial port.

try
    % Determine NumLines empirically for your font, font size, and static text size
    NumLines = 21;
    % Get the contents of the static text box, make a cell if necessary
    Mssg = get(handles.TxtMssg, 'string');
    if iscell(Mssg) == 0
        Mssg={Mssg};
    end
    % Cat on the newly received line
    Mssg = [Mssg; rec_line];
    % trim to length of textbox, last NumLines rows only
    if length(Mssg) > NumLines
        Mssg = Mssg((end-NumLines+1):end);
    end
    % Write Mssg, with a strtrim() in case of any trailing newlines
    set(handles.TxtMssg, 'string', strtrim(Mssg));
catch err
    % Error handling
end

I recommend using try/catch/end with datalogging type applications to prevent a glitched communication from crashing the whole program.