MATLAB GUI的运行原理理解

gui_StateFields =  { 
   'gui_Name' 'gui_Singleton' 'gui_OpeningFcn' 'gui_OutputFcn' 'gui_LayoutFcn' 'gui_Callback'};
gui_Mfile = '';

% 获取文件名
for i=1:length(gui_StateFields)
    if ~isfield(gui_State, gui_StateFields{i})
        error(message('MATLAB:guide:StateFieldNotFound', gui_StateFields{ i }, gui_Mfile));
    elseif isequal(gui_StateFields{i}, 'gui_Name')
        gui_Mfile = [gui_State.(gui_StateFields{i}), '.m'];
    end
end

numargin = length(varargin);

if numargin == 0
    % UNTITLED
    % create the GUI only if we are not in the process of loading it
    % already
    gui_Create = true;
elseif local_isInvokeActiveXCallback(gui_State, varargin{:})
    % UNTITLED(ACTIVEX,...)
    vin{
  
  1} = gui_State.gui_Name;
    vin{
  
  2} = [get(varargin{
  
  1}.Peer, 'Tag'), '_', varargin{end}];
    vin{
  
  3} = varargin{
  
  1};
    vin{
  
  4} = varargin{end-1};
    vin{
  
  5} = guidata(varargin{
  
  1}.Peer);
    feval(vin{:});
    return;
elseif local_isInvokeHGCallback(gui_State, varargin{:})
    % UNTITLED('CALLBACK',hObject,eventData,handles,...)
    gui_Create = false;
else
    % UNTITLED(...)
    % create the GUI and hand varargin to the openingfcn
    gui_Create = true;
end

if ~gui_Create
    ... %省略中间的代码
else
    if gui_State.gui_Singleton
        gui_SingletonOpt = 'reuse';
    else
        gui_SingletonOpt = 'new';
    end

    % Check user passing 'visible' P/V pair first so that its value can be
    % used by oepnfig to prevent flickering
    gui_Visible = 'auto';
    gui_VisibleInput = '';
    for index=1:2:length(varargin)
        if length(varargin) == index || ~ischar(varargin{index})
            break;
        end

        % Recognize 'visible' P/V pair
        len1 = min(length('visible'),length(varargin{index}));
        len2 = min(length('off'),length(varargin{index+1}));
        if ischar(varargin{index+1}) && strncmpi(varargin{index},'visible',len1) && len2 > 1
            if strncmpi(varargin{index+1},'off',len2)
                gui_Visible = 'invisible';
                gui_VisibleInput = 'off';
            elseif strncmpi(varargin{index+1},'on',len2)
                gui_Visible = 'visible';
                gui_VisibleInput = 'on';
            end
        end
    end
    ...%省略下面代码，这些代码在下面分块分析
end
%函数返回

    % Do feval on layout code in m-file if it exists
    gui_Exported = ~isempty(gui_State.gui_LayoutFcn);
    % this application data is used to indicate the running mode of a GUIDE
    % GUI to distinguish it from the design mode of the GUI in GUIDE. it is
    % only used by actxproxy at this time.   
    %直接把数据保存在UI中
    setappdata(0,genvarname(['OpenGuiWhenRunning_', gui_State.gui_Name]),1);
    if gui_Exported
        gui_hFigure = feval(gui_State.gui_LayoutFcn, gui_SingletonOpt);

        % make figure invisible here so that the visibility of figure is
        % consistent in OpeningFcn in the exported GUI case
        if isempty(gui_VisibleInput)
            gui_VisibleInput = get(gui_hFigure,'Visible');
        end
        set(gui_hFigure,'Visible','off')

        % openfig (called by local_openfig below) does this for guis without
        % the LayoutFcn. Be sure to do it here so guis show up on screen.
        movegui(gui_hFigure,'onscreen');
    else
        gui_hFigure = local_openfig(gui_State.gui_Name, gui_SingletonOpt, gui_Visible);
        % If the figure has InGUIInitialization it was not completely created
        % on the last pass.  Delete this handle and try again.
        if isappdata(gui_hFigure, 'InGUIInitialization')
            delete(gui_hFigure);
            gui_hFigure = local_openfig(gui_State.gui_Name, gui_SingletonOpt, gui_Visible);
        end
    end
    if isappdata(0, genvarname(['OpenGuiWhenRunning_', gui_State.gui_Name]))
%       移除相应的变量
        rmappdata(0,genvarname(['OpenGuiWhenRunning_', gui_State.gui_Name]));
    end

    % Set flag to indicate starting GUI initialization
    setappdata(gui_hFigure,'InGUIInitialization',1);

    % Fetch GUIDE Application options
    gui_Options = getappdata(gui_hFigure,'GUIDEOptions');
    % Singleton setting in the GUI M-file takes priority if different
    gui_Options.singleton = gui_State.gui_Singleton;

    if ~isappdata(gui_hFigure,'GUIOnScreen')
        % Adjust background color
        if gui_Options.syscolorfig
            set(gui_hFigure,'Color', get(0,'DefaultUicontrolBackgroundColor'));
        end

        % Generate HANDLES structure and store with GUIDATA. If there is
        % user set GUI data already, keep that also.
        data = guidata(gui_hFigure);
        handles = guihandles(gui_hFigure);
        if ~isempty(handles)
            if isempty(data)
                data = handles;
            else
                names = fieldnames(handles);
                for k=1:length(names)
                    data.(char(names(k)))=handles.(char(names(k)));
                end
            end
        end
        guidata(gui_hFigure, data);
    end

% Apply input P/V pairs other than 'visible'
    for index=1:2:length(varargin)
        if length(varargin) == index || ~ischar(varargin{index})
            break;
        end

        len1 = min(length('visible'),length(varargin{index}));
        if ~strncmpi(varargin{index},'visible',len1)
            try set(gui_hFigure, varargin{index}, varargin{index+1}), catch break, end
        end
    end

    % If handle visibility is set to 'callback', turn it on until finished
    % with OpeningFcn
    gui_HandleVisibility = get(gui_hFigure,'HandleVisibility');
    if strcmp(gui_HandleVisibility, 'callback')
        set(gui_hFigure,'HandleVisibility', 'on');
    end

%    开始运行gui_OpeningFcn
    feval(gui_State.gui_OpeningFcn, gui_hFigure, [], guidata(gui_hFigure), varargin{:});

    if isscalar(gui_hFigure) && ishghandle(gui_hFigure)
        % Handle the default callbacks of predefined toolbar tools in this
        % GUI, if any
        guidemfile('restoreToolbarToolPredefinedCallback',gui_hFigure); 

        % Update handle visibility
        set(gui_hFigure,'HandleVisibility', gui_HandleVisibility);

        % Call openfig again to pick up the saved visibility or apply the
        % one passed in from the P/V pairs
%         设置fig的可见性？
        if ~gui_Exported
            gui_hFigure = local_openfig(gui_State.gui_Name, 'reuse',gui_Visible);
        elseif ~isempty(gui_VisibleInput)
            set(gui_hFigure,'Visible',gui_VisibleInput);
        end
        if strcmpi(get(gui_hFigure, 'Visible'), 'on')
            figure(gui_hFigure);

            if gui_Options.singleton
                setappdata(gui_hFigure,'GUIOnScreen', 1);
            end
        end

        % Done with GUI initialization
        if isappdata(gui_hFigure,'InGUIInitialization')
            rmappdata(gui_hFigure,'InGUIInitialization');
        end

  % If handle visibility is set to 'callback', turn it on until
        % finished with OutputFcn
        gui_HandleVisibility = get(gui_hFigure,'HandleVisibility');
        if strcmp(gui_HandleVisibility, 'callback')
            set(gui_hFigure,'HandleVisibility', 'on');
        end
        gui_Handles = guidata(gui_hFigure);
    else
        gui_Handles = [];
    end

    if nargout
        [varargout{1:nargout}] = feval(gui_State.gui_OutputFcn, gui_hFigure, [], gui_Handles);
    else
        feval(gui_State.gui_OutputFcn, gui_hFigure, [], gui_Handles);
    end

    if isscalar(gui_hFigure) && ishghandle(gui_hFigure)
        set(gui_hFigure,'HandleVisibility', gui_HandleVisibility);
    end

if ~gui_Create
    % In design time, we need to mark all components possibly created in
    % the coming callback evaluation as non-serializable. This way, they
    % will not be brought into GUIDE and not be saved in the figure file
    % when running/saving the GUI from GUIDE.
    designEval = false;
    if (numargin>1 && ishghandle(varargin{
  
  2}))
        fig = varargin{
  
  2};
        while ~isempty(fig) && ~ishghandle(fig,'figure')
            fig = get(fig,'parent');
        end

        designEval = isappdata(0,'CreatingGUIDEFigure') || (isscalar(fig)&&isprop(fig,'GUIDEFigure'));
    end

    if designEval
        beforeChildren = findall(fig);
    end

    % evaluate the callback now
    varargin{
  
  1} = gui_State.gui_Callback;
    if nargout
        [varargout{
  
  1:nargout}] = feval(varargin{:});
    else       
        feval(varargin{:});
    end

    % Set serializable of objects created in the above callback to off in
    % design time. Need to check whether figure handle is still valid in
    % case the figure is deleted during the callback dispatching.
    if designEval && ishghandle(fig)
        set(setdiff(findall(fig),beforeChildren), 'Serializable','off');
    end
else
...
end
%程序返回