matlab 应用程序设计器在新应用程序中加载图像

Question

我正在使用App Designer并尝试将图像（单击后）从 MainApp 加载到 App2 并使用 MainApp 中名为imagePath的全局变量直接显示（参见屏幕截图），我在其中存储字符串（'metro-station.png ') 和 App2 中的Startup function ，我将 ImageSource 设置为该路径。

但这似乎不起作用。

function startupFcn(app)
    app.Image.ImageSource = fullfile(imagePath);
end

有没有其他方法可以做到这一点？

Answer 1

您不需要global variable来在两个应用程序之间共享数据。

在应用程序之间交换数据的一种可能方式是：

在 MainApp 中：

• 定义一个public property （要与第二个 App 共享的变量）
• 在 function 或 MainApp 的回调中初始化它
• 在调用第二个 App 时，只需将“App”句柄作为输入参数传递，这样就可以将 MainApp 的所有公共属性共享给第二个 App

在第二个应用程序中：

• 定义一个private property来保存来自 MainApp 的输入参数
• 在startupFcn中将输入参数分配给此类属性
• 从这一刻起，您可以访问 ManApp 的所有public properties ，包括您希望从 MainApp 传递给第二个 App 的特定属性

此方法的优点之一（但同时也是缺点之一）是您可以修改第二个 App 中的任何 MainApp 公共属性，尤其是输入参数

如果您不想（不需要）给第二个 App 修改 MainApp 属性的可能性：

在主应用程序中：

• 如果您想在调用 Second App 的函数之外的其他函数中更改 Second App 的输入参数，您可以在 MainApp 中将其定义为private property ，以便您可以在任何 MainApp function / callback中访问它
• 否则，您可以在调用第二个 App 的 MainApp 的function / callback中定义一个local variable并将其用作输入参数
• 然后，在调用第二个应用程序时，您只能将此property或local变量传递给第二个应用程序

在第二个应用程序中：

• 定义一个private property来存储输入参数
• 在 s tartupFcn中将输入parameter分配给该property
• 从这一刻起，所有第二个 App function / 回调都可以访问 ManApp 输入参数

这种方法的优点（但同时也有缺点）是：

• 由于输入参数是传值的，所以当你关闭第二个App时，对输入参数的任何修改都会丢失
• 第二个 App 无权访问 MainApp 的公共属性

其他分享方式也可以。

在以下代码中提出的解决方案中，我使用了（为简单起见）第一种方法。

MainApp显示 6 个Images和Import pushbutton ，按下该按钮会打开second App并显示在 MainApp 中选择的图像：

• 图像通过点击被选中，选中时，选中（再次点击取消选中）label 出现在其上方
• 再次单击图像，取消选择图像
• 单击另一个图像，选择图像并取消选择之前选择的图像（如果有）
• The pushbutton is enabled only if an image has been selected, when pressed, the second App opens.

second App只是显示在 MainApp 中选择的图像， Close pushbutton允许关闭它。

MainApp 包括：（见下图）：

• 6 图像对象：app.Image1，...
• 6 个标签：app.img_1_selected，...
• 1 个按钮：app.ImportButton

app2 包括（见下图）：

• 1 图片 object：app.Image
• 1 Label：app.Label
• 1 个按钮：关闭按钮

主应用程序代码

为简单起见，MainApp 中图像的路径和文件名是硬编码的，但您可以轻松实现 function 来动态加载它们。

在public properties集中，您可以找到以下内容：

• PathSelectedImage ：用于存储要传递给第二个 App 的所选图像的路径和文件名的属性
• ImgSelectionStr ：存储图像标签句柄的数组
• ImageSet ：一个数组，用于存储图像 object 的句柄

这两个 arrays 允许在处理图像和字符串时使用 for 循环并避免代码重复。

arrays 在 startupFcn function 中初始化。

要访问存储在 arrays 中的对象的属性，您必须使用set / get函数而不是点表示法。

ImageClickedFcn callback是为每个图像定义的； 它只是简单地设置图像的 ID 并调用SetUnset_Selection function。

SetUnset_Selection function管理图像的选择，它们上方的 label 并启用/禁用Import pushbutton

classdef MainApp_exported < matlab.apps.AppBase

   % Properties that correspond to app components
   properties (Access = public)
      MainAppUIFigure  matlab.ui.Figure
      img_1_selected   matlab.ui.control.Label
      img_2_selected   matlab.ui.control.Label
      img_3_selected   matlab.ui.control.Label
      img_4_selected   matlab.ui.control.Label
      img_5_selected   matlab.ui.control.Label
      img_6_selected   matlab.ui.control.Label
      ImportButton     matlab.ui.control.Button
      Image_6          matlab.ui.control.Image
      Image_5          matlab.ui.control.Image
      Image_4          matlab.ui.control.Image
      Image_3          matlab.ui.control.Image
      Image_2          matlab.ui.control.Image
      Image_1          matlab.ui.control.Image
   end

   properties (Access = public)
      PathSelectedImage;   % Path and filename of the selected image
      SelectedImageId;     % Id of the selected image
      SelectedImagePrevId; % Id of the previously selected image
      ImgSelectionStr;     % Array of Label objects
      ImageSet;            % Array of Image objects
      app2_h;              % handle to access app2
   end
   
   methods (Access = private)
      
      % SetUnset_Selection: functin that manages the activaton of:
      %  - selection labels over the images 
      %  - path and filename of the selected image
      function SetUnset_Selection(app,SelectedImg)
         % Selet the image object from the ImageSet array
         tmp = app.ImageSet(SelectedImg);
         % Get the path and filename of the selected imae
         app.PathSelectedImage = get(tmp,'ImageSource');

         % Save the ID of the previouusly selected image
         if(app.SelectedImagePrevId ~= app.SelectedImageId)
            app.SelectedImagePrevId = app.SelectedImageId;
         else
            app.SelectedImagePrevId = -1;
         end
         
         % Set the ID of the selected image
         app.SelectedImageId = SelectedImg;

         % Selet the image label object from the ImgSelectionStr array
         tmp = app.ImgSelectionStr(SelectedImg);
         % Visualize the label of the selected image and hide the label of
         % the previously selected image and turns on the Import pushbutton
         if(strcmp(get(tmp,'Visible'),"off"))
            set(tmp,'Visible',"on",'Text','Selected (click again to unselect)');
            app.ImportButton.Enable = "on";
         else
            set(tmp,'Visible',"off")
            app.ImportButton.Enable = "off";
         end
         if(app.SelectedImagePrevId > 0)
            set(app.ImgSelectionStr(app.SelectedImagePrevId),'Visible','off');
         end
      end
   end
   

   % Callbacks that handle component events
   methods (Access = private)

      % Code that executes after component creation
      function startupFcn(app)
         % Initialize the handle to access app2
         app.app2_h = [];
         % Initialize the ID of the previously selected image
         app.SelectedImagePrevId = -1;
         % Initialize the ID of the selected image
         app.SelectedImageId = -1;
         % Store the image label objects in the ImgSelectionStr array
         % The array is used to easily access the label objects and avoid
         % duplication in the code
         app.ImgSelectionStr(1) = app.img_1_selected;
         app.ImgSelectionStr(2) = app.img_2_selected;
         app.ImgSelectionStr(3) = app.img_3_selected;
         app.ImgSelectionStr(4) = app.img_4_selected;
         app.ImgSelectionStr(5) = app.img_5_selected;
         app.ImgSelectionStr(6) = app.img_6_selected;

         % Store the image objects in the ImageSet array
         % The array is used to easily access the label objects and avoid
         % duplication in the code
         app.ImageSet(1) = app.Image_1;
         app.ImageSet(2) = app.Image_2;
         app.ImageSet(3) = app.Image_3;
         app.ImageSet(4) = app.Image_4;
         app.ImageSet(5) = app.Image_5;
         app.ImageSet(6) = app.Image_6;

      end

      % Button pushed function: ImportButton
      function ImportButtonPushed(app, event)
         % Turn off the Import pushbutton (will be turned on in the
         % SetUnset_Selection function
         app.ImportButton.Enable = "off";
         % Open the app2 that shows the selected image
         app.app2_h=app2(app);
      end

      % Image clicked function: Image_1
      function Image_1Clicked(app, event)
         % Set the ID of the selected image
         Sel_Img_Id = 1;
         % Call SetUnset_Selection to manage the image labels and get the
         % path and filename of the selected image
         SetUnset_Selection(app,Sel_Img_Id);

      end

      % Image clicked function: Image_2
      function Image_2Clicked(app, event)
         % Set the ID of the selected image
         Sel_Img_Id = 2;
         % Call SetUnset_Selection to manage the image labels and get the
         % path and filename of the selected image
         SetUnset_Selection(app,Sel_Img_Id);

      end

      % Image clicked function: Image_3
      function Image_3Clicked(app, event)
         % Set the ID of the selected image
         Sel_Img_Id = 3;
         % Call SetUnset_Selection to manage the image labels and get the
         % path and filename of the selected image
         SetUnset_Selection(app,Sel_Img_Id);

      end

      % Image clicked function: Image_4
      function Image_4Clicked(app, event)
         % Set the ID of the selected image
         Sel_Img_Id = 4;
         % Call SetUnset_Selection to manage the image labels and get the
         % path and filename of the selected image
         SetUnset_Selection(app,Sel_Img_Id);

      end

      % Image clicked function: Image_5
      function Image_5Clicked(app, event)
         % Set the ID of the selected image
         Sel_Img_Id = 5;
         % Call SetUnset_Selection to manage the image labels and get the
         % path and filename of the selected image
         SetUnset_Selection(app,Sel_Img_Id);

      end

      % Image clicked function: Image_6
      function Image_6Clicked(app, event)
         % Set the ID of the selected image
         Sel_Img_Id = 6;
         % Call SetUnset_Selection to manage the image labels and get the
         % path and filename of the selected image
         SetUnset_Selection(app,Sel_Img_Id);

      end
   end

   % Component initialization
   methods (Access = private)

      % Create UIFigure and components
      function createComponents(app)

         % Get the file path for locating images
         pathToMLAPP = fileparts(mfilename('fullpath'));

         % Create MainAppUIFigure and hide until all components are created
         app.MainAppUIFigure = uifigure('Visible', 'off');
         app.MainAppUIFigure.IntegerHandle = 'on';
         app.MainAppUIFigure.Position = [100 100 580 431];
         app.MainAppUIFigure.Name = 'MainApp';
         app.MainAppUIFigure.Tag = 'App1_FIGURE';

         % Create Image_1
         app.Image_1 = uiimage(app.MainAppUIFigure);
         app.Image_1.ImageClickedFcn = createCallbackFcn(app, @Image_1Clicked, true);
         app.Image_1.Position = [34 301 118 92];
         app.Image_1.ImageSource = fullfile(pathToMLAPP, 'IMG', 'img_1.jpg');

         % Create Image_2
         app.Image_2 = uiimage(app.MainAppUIFigure);
         app.Image_2.ImageClickedFcn = createCallbackFcn(app, @Image_2Clicked, true);
         app.Image_2.Position = [34 176 118 92];
         app.Image_2.ImageSource = fullfile(pathToMLAPP, 'IMG', 'img_2.jpg');

         % Create Image_3
         app.Image_3 = uiimage(app.MainAppUIFigure);
         app.Image_3.ImageClickedFcn = createCallbackFcn(app, @Image_3Clicked, true);
         app.Image_3.Position = [34 53 118 92];
         app.Image_3.ImageSource = fullfile(pathToMLAPP, 'IMG', 'img_3.jpg');

         % Create Image_4
         app.Image_4 = uiimage(app.MainAppUIFigure);
         app.Image_4.ImageClickedFcn = createCallbackFcn(app, @Image_4Clicked, true);
         app.Image_4.Position = [413 301 118 92];
         app.Image_4.ImageSource = fullfile(pathToMLAPP, 'IMG', 'img_4.jpg');

         % Create Image_5
         app.Image_5 = uiimage(app.MainAppUIFigure);
         app.Image_5.ImageClickedFcn = createCallbackFcn(app, @Image_5Clicked, true);
         app.Image_5.Position = [413 176 118 92];
         app.Image_5.ImageSource = fullfile(pathToMLAPP, 'IMG', 'img_5.jpg');

         % Create Image_6
         app.Image_6 = uiimage(app.MainAppUIFigure);
         app.Image_6.ImageClickedFcn = createCallbackFcn(app, @Image_6Clicked, true);
         app.Image_6.Position = [413 53 118 92];
         app.Image_6.ImageSource = fullfile(pathToMLAPP, 'IMG', 'img_6.jpg');

         % Create ImportButton
         app.ImportButton = uibutton(app.MainAppUIFigure, 'push');
         app.ImportButton.ButtonPushedFcn = createCallbackFcn(app, @ImportButtonPushed, true);
         app.ImportButton.BackgroundColor = [0.9294 0.6941 0.1255];
         app.ImportButton.FontSize = 14;
         app.ImportButton.FontWeight = 'bold';
         app.ImportButton.Enable = 'off';
         app.ImportButton.Position = [211 203 158 39];
         app.ImportButton.Text = 'Import';

         % Create img_6_selected
         app.img_6_selected = uilabel(app.MainAppUIFigure);
         app.img_6_selected.FontWeight = 'bold';
         app.img_6_selected.FontColor = [1 0 0];
         app.img_6_selected.Visible = 'off';
         app.img_6_selected.Position = [350 144 195 22];
         app.img_6_selected.Text = 'Selected (click again to unselect)';

         % Create img_5_selected
         app.img_5_selected = uilabel(app.MainAppUIFigure);
         app.img_5_selected.FontWeight = 'bold';
         app.img_5_selected.FontColor = [1 0 0];
         app.img_5_selected.Visible = 'off';
         app.img_5_selected.Position = [350 267 195 22];
         app.img_5_selected.Text = 'Selected (click again to unselect)';

         % Create img_4_selected
         app.img_4_selected = uilabel(app.MainAppUIFigure);
         app.img_4_selected.FontWeight = 'bold';
         app.img_4_selected.FontColor = [1 0 0];
         app.img_4_selected.Visible = 'off';
         app.img_4_selected.Position = [350 393 195 22];
         app.img_4_selected.Text = 'Selected (click again to unselect)';

         % Create img_3_selected
         app.img_3_selected = uilabel(app.MainAppUIFigure);
         app.img_3_selected.FontWeight = 'bold';
         app.img_3_selected.FontColor = [1 0 0];
         app.img_3_selected.Visible = 'off';
         app.img_3_selected.Position = [48 144 195 22];
         app.img_3_selected.Text = 'Selected (click again to unselect)';

         % Create img_2_selected
         app.img_2_selected = uilabel(app.MainAppUIFigure);
         app.img_2_selected.FontWeight = 'bold';
         app.img_2_selected.FontColor = [1 0 0];
         app.img_2_selected.Visible = 'off';
         app.img_2_selected.Position = [48 267 195 22];
         app.img_2_selected.Text = 'Selected (click again to unselect)';

         % Create img_1_selected
         app.img_1_selected = uilabel(app.MainAppUIFigure);
         app.img_1_selected.FontWeight = 'bold';
         app.img_1_selected.FontColor = [1 0 0];
         app.img_1_selected.Visible = 'off';
         app.img_1_selected.Position = [48 393 195 22];
         app.img_1_selected.Text = 'Selected (click again to unselect)';

         % Show the figure after all components are created
         app.MainAppUIFigure.Visible = 'on';
      end
   end

   % App creation and deletion
   methods (Access = public)

      % Construct app
      function app = MainApp_exported

         % Create UIFigure and components
         createComponents(app)

         % Register the app with App Designer
         registerApp(app, app.MainAppUIFigure)

         % Execute the startup function
         runStartupFcn(app, @startupFcn)

         if nargout == 0
            clear app
         end
      end

      % Code that executes before app deletion
      function delete(app)

         % Delete UIFigure when app is deleted
         delete(app.MainAppUIFigure)
      end
   end
end

第二个应用程序代码

private property MainApp用于存放MainApp的入参（即MainApp句柄）

startupFcn只是从输入参数中检索要显示的图像的路径和名称，并在图像上方设置 label。

classdef app2_exported < matlab.apps.AppBase

   % Properties that correspond to app components
   properties (Access = public)
      App2ImageDisplayUIFigure  matlab.ui.Figure
      Label                     matlab.ui.control.Label
      CloseButton               matlab.ui.control.Button
      Image                     matlab.ui.control.Image
   end

   
   properties (Access = private)
      MainApp; % Handle of the calling app (app1)
   end
   

   % Callbacks that handle component events
   methods (Access = private)

      % Code that executes after component creation
      function startupFcn(app, CallingApp)
         % Set the handle of the calling app
         app.MainApp = CallingApp;
         % Load the select image
         app.Image.ImageSource = CallingApp.PathSelectedImage;
         % Print the name and the ID of the diplayed image
         [~,name,~] = fileparts(app.Image.ImageSource);
         img_id=CallingApp.SelectedImageId;
         str=sprintf('Name: %s\nPosition: %d',name,img_id);
         app.Label.Text = str;
         % Set the Label of the selected image in app1 as "Imported"
         tmp=CallingApp.ImgSelectionStr(img_id);
         set(tmp,'text','Imported');

      end

      % Button pushed function: CloseButton
      function CloseButtonPushed(app, event)
         % Get the handle of the label of the selected image in app1
         tmp=app.MainApp.ImgSelectionStr(app.MainApp.SelectedImageId);
         % Update the label of displayed image in the calling app before
         % closing the app2
         set(tmp,'text','App2 closed, select a in image');
         app.MainApp.app2_h = [];
         delete(app);
      end

      % Close request function: App2ImageDisplayUIFigure
      function App2ImageDisplayUIFigureCloseRequest(app, event)
         tmp=app.MainApp.ImgSelectionStr(app.MainApp.SelectedImageId);
         % Update the label of displayed image in the calling app before
         % closing the app2
         set(tmp,'text','App2 closed, select a in image');
         app.MainApp.app2_h = [];
         delete(app);
         
      end
   end

   % Component initialization
   methods (Access = private)

      % Create UIFigure and components
      function createComponents(app)

         % Create App2ImageDisplayUIFigure and hide until all components are created
         app.App2ImageDisplayUIFigure = uifigure('Visible', 'off');
         app.App2ImageDisplayUIFigure.IntegerHandle = 'on';
         app.App2ImageDisplayUIFigure.Position = [100 100 655 536];
         app.App2ImageDisplayUIFigure.Name = 'App2 - Image Display';
         app.App2ImageDisplayUIFigure.CloseRequestFcn = createCallbackFcn(app, @App2ImageDisplayUIFigureCloseRequest, true);
         app.App2ImageDisplayUIFigure.HandleVisibility = 'on';
         app.App2ImageDisplayUIFigure.Tag = 'app2_FIGURE';

         % Create Image
         app.Image = uiimage(app.App2ImageDisplayUIFigure);
         app.Image.Position = [33 122 390 295];

         % Create CloseButton
         app.CloseButton = uibutton(app.App2ImageDisplayUIFigure, 'push');
         app.CloseButton.ButtonPushedFcn = createCallbackFcn(app, @CloseButtonPushed, true);
         app.CloseButton.Position = [445 273 98 34];
         app.CloseButton.Text = 'Close';

         % Create Label
         app.Label = uilabel(app.App2ImageDisplayUIFigure);
         app.Label.WordWrap = 'on';
         app.Label.Position = [59 448 524 73];
         app.Label.Text = '';

         % Show the figure after all components are created
         app.App2ImageDisplayUIFigure.Visible = 'on';
      end
   end

   % App creation and deletion
   methods (Access = public)

      % Construct app
      function app = app2_exported(varargin)

         % Create UIFigure and components
         createComponents(app)

         % Register the app with App Designer
         registerApp(app, app.App2ImageDisplayUIFigure)

         % Execute the startup function
         runStartupFcn(app, @(app)startupFcn(app, varargin{:}))

         if nargout == 0
            clear app
         end
      end

      % Code that executes before app deletion
      function delete(app)

         % Delete UIFigure when app is deleted
         delete(app.App2ImageDisplayUIFigure)
      end
   end
end

下图显示了两个“正在工作”的应用程序。

希望这可以帮助。 卡普拉