一、如何在一个callback回调函数中调用另一个回调函数

  网上找了好多帖子，都是在答非所问，我最终失去了耐心，自己去写个小demo碰碰运气吧，然后非常幸运，我解决了，哈哈，看下面的小案例。
图形界面非常简单，如下图所示：

系统生成了一堆代码，里面也包含回调，代码如下：

function varargout = test(varargin)
% TEST MATLAB code for test.fig
%      TEST, by itself, creates a new TEST or raises the existing
%      singleton*.
%
%      H = TEST returns the handle to a new TEST or the handle to
%      the existing singleton*.
%
%      TEST('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in TEST.M with the given input arguments.
%
%      TEST('Property','Value',...) creates a new TEST or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before test_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to test_OpeningFcn via varargin.
%
%      *See GUI Options on GUIDE's Tools menu.  Choose "GUI allows only one
%      instance to run (singleton)".
%
% See also: GUIDE, GUIDATA, GUIHANDLES

% Edit the above text to modify the response to help test

% Last Modified by GUIDE v2.5 12-Nov-2019 19:14:56

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @test_OpeningFcn, ...
                   'gui_OutputFcn',  @test_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{
    1})
    gui_State.gui_Callback = str2func(varargin{
    1});
end

if nargout
    [varargout{
    1:nargout}] = gui_mainfcn(gui_State, varargin{
    :});
else
    gui_mainfcn(gui_State, varargin{
    :});
end
% End initialization code - DO NOT EDIT


% --- Executes just before test is made visible.
function test_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% varargin   command line arguments to test (see VARARGIN)

% Choose default command line output for test
handles.output = hObject;

% Update handles structure
guidata(hObject, handles);

% UIWAIT makes test wait for user response (see UIRESUME)
% uiwait(handles.figure1);


% --- Outputs from this function are returned to the command line.
function varargout = test_OutputFcn(hObject, eventdata, handles) 
% varargout  cell array for returning output args (see VARARGOUT);
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Get default command line output from handles structure
varargout{
    1} = handles.output;


% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
disp('aaaaa');


% --- Executes on button press in pushbutton2.
function pushbutton2_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
disp('bbbbb');

% --- Executes on button press in pushbutton3.
function pushbutton3_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
pushbutton1_Callback(hObject, eventdata, handles);
pushbutton2_Callback(hObject, eventdata, handles);

其中pushbutton1_Callback、pushbutton2_Callback、pushbuton3_Callback分别对应A、B、C三个按钮的点击回调函数。
实现功能：
1、点击按钮A，可以打印aaaa
2、点击按钮B，可以打印bbbb
3、点击按钮C，可以执行按钮A和B的回调，打印aaaa bbbb

二、如何在自定义一个函数，然后调用按钮等控件的Callback回调函数呢？

  我进行了一系列摸索和尝试。发现方法也不难，看下面的小案例：
这个小案例的是基于上一个案例改的，代码如下：

function varargout = test(varargin)
% TEST MATLAB code for test.fig
%      TEST, by itself, creates a new TEST or raises the existing
%      singleton*.
%
%      H = TEST returns the handle to a new TEST or the handle to
%      the existing singleton*.
%
%      TEST('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in TEST.M with the given input arguments.
%
%      TEST('Property','Value',...) creates a new TEST or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before test_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to test_OpeningFcn via varargin.
%
%      *See GUI Options on GUIDE's Tools menu.  Choose "GUI allows only one
%      instance to run (singleton)".
%
% See also: GUIDE, GUIDATA, GUIHANDLES

% Edit the above text to modify the response to help test

% Last Modified by GUIDE v2.5 12-Nov-2019 19:14:56

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @test_OpeningFcn, ...
                   'gui_OutputFcn',  @test_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{
    1})
    gui_State.gui_Callback = str2func(varargin{
    1});
end

if nargout
    [varargout{
    1:nargout}] = gui_mainfcn(gui_State, varargin{
    :});
else
    gui_mainfcn(gui_State, varargin{
    :});
end
% End initialization code - DO NOT EDIT


% --- Executes just before test is made visible.
function test_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% varargin   command line arguments to test (see VARARGIN)

% Choose default command line output for test
handles.output = hObject;

% Update handles structure
guidata(hObject, handles);

% UIWAIT makes test wait for user response (see UIRESUME)
% uiwait(handles.figure1);


% --- Outputs from this function are returned to the command line.
function varargout = test_OutputFcn(hObject, eventdata, handles) 
% varargout  cell array for returning output args (see VARARGOUT);
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Get default command line output from handles structure
varargout{
    1} = handles.output;


% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
disp('aaaaa');


% --- Executes on button press in pushbutton2.
function pushbutton2_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
disp('bbbbb');

function myfun(hObject, eventdata, handles)
pushbutton1_Callback(hObject, eventdata, handles);
pushbutton2_Callback(hObject, eventdata, handles);

% --- Executes on button press in pushbutton3.
function pushbutton3_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
myfun(hObject, eventdata, handles);

其中pushbutton1_Callback、pushbutton2_Callback、pushbuton3_Callback分别对应A、B、C三个按钮的点击回调函数，myfun是我自定义的函数，我仿照回调函数的格式，传了三个参数hObject, eventdata, handles进去，结果成功调通了程序。
实现功能：
1、点击按钮A，可以打印aaaa
2、点击按钮B，可以打印bbbb
3、点击按钮C，可以执行我自定义的myfun函数，而myfun函数调用了按钮A和B的回调，打印出了aaaa bbbb。
也是项目需要才研究了这个东西，运气不错，顺利调通程序，哈哈哈。