Shows how to create a responsive gui with Matlab without using multithreading.

ResponsiveGui.m

%
% PURPOSE
%
%   Shows how to create a responsive gui with Matlab without using
%   multithreading.
%
% SYNTAX:
%
%   [] = ResponsiveGui();
%
% REMARKS:
%
%   See http://stackoverflow.com/q/28364243/684399
%

%% --- Entry point
function [] = ResponsiveGui()
%[
    createGui();
%]
end

%% --- Events in the gui
function [] = onCloseRequest(dlg)
%[
    % If already in computation mode    
    if (~isempty(get(dlg, 'UserData')))
        % Just indicate close is requested and leave immediatly
        set(dlg, 'UserData', 'CloseRequested');
        data = guidata(dlg);
        set(data.handles.btnGoCancel, 'Enable', 'off', 'String', 'Cancelling...');
        return;
    end
    
    % Immediate close
    delete(dlg);
%]
end
function [] = onGoCancelClick(dlg)
%[
    % If already in computation mode    
    if (~isempty(get(dlg, 'UserData')))
        % Just indicate cancel is requested and leave immediatly
        set(dlg, 'UserData', 'CancelRequested');
        data = guidata(dlg);
        set(data.handles.btnGoCancel, 'Enable', 'off', 'String', 'Cancelling...');
        return;
    end
    
    % Go into computation mode
    [settings, err] = tryReadSettings(dlg);
    if (~isempty(err))
        waitfor(msgbox(err.message, 'Invalid settings', 'Error', 'Modal'));
    else
        enterComputationMode(dlg);
        err = doProcessing(dlg, settings);
        leaveComputationMode(dlg, err);
    end
%]
end
function [settings, err] = tryReadSettings(dlg)
%[
    data = guidata(dlg);
    
    % Read settings
    err = [];
    try
        n = str2double(get(data.handles.edIterationCount, 'String'));
        if (~isfinite(n) || (n < 1) || (n ~= floor(n)))
            error('Number of iteration must of finite positive integer.');
        end
        settings.NumberOfIterations = n;
    catch err
    end
    if (~isempty(err))
        settings = [];
    end       
%]
end
function [] = enterComputationMode(dlg)
%[
    data = guidata(dlg);
    
    % Disable the settings panel and go into 'running' mode
    %set(data.handles.pnSettings, 'Enable', 'off'); % Unfortunatly enabling/disabling a uipanel as a whole is 
    set(data.handles.edIterationCount, 'Enable', 'off'); % not possible so disabling controls one-by-one instead ...
    set(data.handles.btnGoCancel, 'String', 'Cancel');
    set(dlg, 'UserData', 'Running');
%]
end
function [err] = doProcessing(dlg, settings)
%[
    err = [];
    try
        
        % Connect instrumentation callbacks with the gui
        instrumentation.CheckCancel = @(ratio)onCheckCancel(dlg);
        instrumentation.Progress = @(ratio)onProgress(dlg, ratio);
        
        % Perform the processing
        processing(settings.NumberOfIterations, instrumentation);
        
    catch err
        
        % Either cancel or real error ... handled later.
        
    end
%]
end
function [] = leaveComputationMode(dlg, err)
%[
    data = guidata(dlg);

    % In case close was requested
    guiState = get(dlg, 'UserData');
    if (~isempty(guiState) && strcmp(guiState, 'CloseRequested'))
        % Stop immediatly.
        delete(dlg);
        return;
    end
    
    % In case of error during processing
    if (~isempty(err))
        if (strcmp(err.identifier, 'System:OperationCanceledException'))
            % Just indicate user canceled operations.
            waitfor(msgbox('Operations canceled by user.', 'Processing canceled', 'Help', 'Modal'));
        else
            % Here would be better have nice dialog to report processing error 
            % with callstack + some copy to clipboard button for bug report with 
            % OS/ARCH/Etc details...
            waitfor(msgbox(err.message, 'Processing error', 'Error', 'Modal'));
        end
    end
        
    % Reset GUI to normal state
    set(dlg, 'UserData', []);
    set(data.handles.btnGoCancel, 'Enable', 'on', 'String', 'Go');    
    uiprogress(data.handles.pbProgress, 0.0);
    %set(data.handles.pnSettings, 'Enable', 'off'); % Unfortunatly enabling/disabling a uipanel as a whole is 
    set(data.handles.edIterationCount, 'Enable', 'on'); % not possible so re-enabling controls one-by-one instead ...
%]
end

%% --- Instrumentation callbacks
function [] = onCheckCancel(dlg)
%[
    % Force interface to process its events
    drawnow();
    
    % Check 'UserData' has not been modified during events processing
    guiState = get(dlg, 'UserData');
    if (~isempty(guiState) && ....
        strcmp(guiState, 'CancelRequested') || strcmp(guiState, 'CloseRequested'))
        error('System:OperationCanceledException', 'Operation canceled');
    end
%]
end
function [] = onProgress(dlg, ratio)
%[
    % Update the progress bar value
    data = guidata(dlg);
    uiprogress(data.handles.pbProgress, ratio);
    
    % Force interface to refresh
    drawnow();
%]
end

%% --- The processing function
function [] = processing(count, instrumentation)
%[
    for ki = 1:count,
        
        instrumentation.CheckCancel();
        instrumentation.Progress((ki-1)/count);
        
        if (ki > 1), pause(1); end
        
        instrumentation.CheckCancel();
        instrumentation.Progress(ki/count);
        
    end
%]
end

%% --- Create the graphical interface
% This is not important how it is created:
% > Could be done with GUIDE ....
% > or with GUI Layout Toolbox (far much better): http://www.mathworks.com/matlabcentral/fileexchange/27758-gui-layout-toolbox
function [dlg] = createGui()
%[
    % Init
    if (verLessThan('matlab', '8.4'))
        figNumberTile = 'Number'; % R2014b        
    else
        figNumberTile = 'NumberTitle'; % Before R2014b    
    end

    % Create the figure
    dlg = figure('Units', 'pixels', ...
                 'Name', 'Responsive GUI', ...
                 'IntegerHandle', 'off', ...
                 'MenuBar', 'none', ...
                 figNumberTile, 'off', ...
                 'Position', [0, 0, 310, 100], ...
                 'Toolbar', 'none', ...
                 'Visible', 'off');
             
    % Add controls
    pnSettings = uipanel('Parent', dlg, 'BackgroundColor', get(dlg, 'Color'), 'Title', 'Computation settings', 'Units', 'pixels', 'Position', [10 30 200 60]);
    edIterationCount = uicontrol('Parent', pnSettings, 'BackgroundColor', [1 1 1], 'Style', 'edit', 'Units', 'pixels', 'Position', [10 15 180 20], 'TooltipString', 'Number of iterations', 'String', '20');
    pbProgress = uiprogress(dlg); set(pbProgress, 'Units', 'pixels', 'Position', [10 10 200 10]);
    btnGoCancel = uicontrol('Parent', dlg, 'String', 'Go', 'Units', 'pixels', 'Position', [220 10 80 80]);
    
    % Attach events
    set(btnGoCancel, 'Callback', @(s, a)onGoCancelClick(dlg));
    set(dlg, 'CloseRequestFcn', @(s, a)onCloseRequest(dlg));
    
    % Save handles for later
    data = guidata(dlg);
    data.handles.pnSettings = pnSettings;
    data.handles.edIterationCount = edIterationCount;
    data.handles.pbProgress = pbProgress;
    data.handles.btnGoCancel = btnGoCancel;
    guidata(dlg, data);
    
    % Make the figure visible
    hh = findobj(dlg, '-property', 'Units');
    set(hh, 'Units', 'Normalized');
    movegui(dlg, 'center');
    set(dlg, 'Visible', 'on');
%]
end

%% --- A waitbar that can be embedded in a GUI figure.
% NB: Obtained from here => http://stackoverflow.com/a/16861297/684399
function h = uiprogress(varargin)
%[
    if ishandle(varargin{1}) && size(varargin, 2) > 1
        ax = varargin{1};
        value = varargin{2};
        p = get(ax,'Child');
        x = get(p,'XData');
        x(3:4) = value;
        set(p,'XData',x)
        return
    end

    bg_color = 'w';
    fg_color = 'r';
    h = axes('Units','pixels',...
        'XLim',[0 1],'YLim',[0 1],...
        'XTick',[],'YTick',[],...
        'Color',bg_color,...
        'XColor',bg_color,'YColor',bg_color, ...
        'Parent', varargin{1});
    patch([0 0 0 0],[0 1 1 0],fg_color,...
        'Parent',h,...
        'EdgeColor','none');%%%,...
        %%'EraseMode','none');
%]    
end