(App Designer) Dropdown menu detect variables in workspace.

13 次查看（过去 30 天）
Saiful Adham Shukor
评论： Ameer Hamza Khan 2019-2-22
I'm try to familiar myself with apps designer. How to create a dropdown menu with the list of variables in workspace. so, user only choose their selected variable/dataset.
  1 个评论
Stephen23
Stephen23 2018-4-24
编辑：Stephen23 2018-4-24

Note that your code will be simpler and more robust when data is passed between functions, e.g. as input/output arguments, nested functions, or using guidata. Magically accessing variable in other workspace is always slow, complex, and liable to bugs. Read this to know more:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Ameer Hamza
Ameer Hamza 2018-4-24
Yes, it is possible. Here is one way. Add a drop-down menu to the app. In the COMPONENT BROWSER right-click app.UIFigure and add a startupFcn callback for figure object. You can define the newly created function like this
function startupFcn(app)
vars = evalin('base', 'whos');
cell_array = cell(size(vars));
for i=1:length(vars)
cell_array{i} = vars(i).name;
end
app.DropDown.Items = cell_array;
end
where DropDown is the name of your drop-down menu. Now start the app, the drop-down menu will enlist all the variables from the workspace.

更多回答（3 个）

Abdelmalek Benaimeur
thank you so much Ameer Hamza please I have a question
i tried the method you gave us and it worked, but the problem i found is when i open the app i've made, and when i add a new matrix in the workspace it doesn't show up automatically in the dropdown menu until i close the app and re-open it again
is there a way to solve this problem please?
  1 个评论
Ameer Hamza Khan
Ameer Hamza Khan 2019-2-22
One way is to use timer callback. You can use a timer to automatically update the menu at regular (say after every 1 second). Instead of writing my code in startupFcn() you can create a new function inside your app, paste this code in it and assign that function to a timer as callback.

请先登录，再进行评论。

Abdelmalek Benaimeur
please could you show me how, beacause i'm new to appdesigner and i didnt' figure out how to do it
  1 个评论
Ameer Hamza Khan
Ameer Hamza Khan 2019-2-22
The attached file contain an example code. In summary i created a property and a callback function.
properties (Access = private)
menu_timer % Description
end
methods (Access = private)
function update_menu(app, ~, ~)
vars = evalin('base', 'whos');
cell_array = cell(size(vars));
for i=1:length(vars)
cell_array{i} = vars(i).name;
end
app.DropDown.Items = cell_array;
end
end
and added following figure startup and close functions:
function startupFcn(app)
app.menu_timer = timer('ExecutionMode', 'fixedRate', ...
'Period', 1, ...
'TimerFcn', @app.update_menu);
start(app.menu_timer);
end
% Close request function: UIFigure
function UIFigureCloseRequest(app, event)
stop(app.menu_timer);
delete(app.menu_timer);
delete(app)
end

请先登录，再进行评论。

Abdelmalek Benaimeur
you are the Best, Ameer, thank you so much

类别

在 Help Center 和 File Exchange 中查找有关 Develop Apps Using App Designer 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by