How can I open a hyperlink from a button callback in AppDesigner?

I am creating an app where I would like to access information via an Edit field and a button. The user can write a specific number (system code) in the EditField and read information in a UITable below. For further reading I'd like to implement a button that calls the webpage where the PDF with additional information is stored. The links to the webpages regarding the selected code are stored as strings in an Excel file. So far I can access the right links as strings but I struggle to call the actual website. So far I have tried the "web" and "webpage" functions.

Initialization of public properties:

 properties (Access = public)
        links = readtable("guide_filling_code_neu_2.xlsx", 'Range', 'K1:K87','PreserveVariableNames', true);
        codeguide = readtable("guide_filling_code_neu_2.xlsx", 'Range', 'A1:J87', 'PreserveVariableNames', true);
        
    end

In the button callback function:

filling_code = app.SearchforfillingcodeEditField.Value;
            r_1 = ismember(app.codeguide.('Filling Code'),filling_code);                                              %Ermittlung der richtigen Reihe nach Eingabe
            row = find(r_1);
            linkstring = app.links(row,:);
            linkstring = string(linkstring{:,:});
            web(linkstring,'UniformOutput', false)
            

The execution brings the error

Error using web
Non-scalar in Uniform output, at index 1, output 1.
Set 'UniformOutput' to false.

Error in guide_filling_system/DetailsPDFButtonPushed (line 1445)
            web(linkstring,'UniformOutput', false)

[Fangjun Jiang]

Can you paste the value of linkstring when web() is executed? I am suprised by the error message because no output is needed.

[Johannes]

Yes I have tried that in a test script. value of linkstring is the URL as a string

Answer 1

[Cris LaPierre]

I get an error when using the command you shared

linkstring = 'https://www.mathworks.com';
web(linkstring,'UniformOutput', false)

Error using web
First argument must be text.

If I make the input argument a string, I do not.

web(linkstring,'UniformOutput', 'false')

However, I'm not sure you even need that name-value pair. At least, I can't find it documented for this function. Why not just use web(linkstring)?

One concern I would have is this code

linkstring = app.links(row,:);
linkstring = string(linkstring{:,:});

We can't see what your variable values are, but a url should not span multiple colums. If this is a workaround because your url is a character array, I suggest using the "TextType","string" option in readtable instead.

[Fangjun Jiang]

You mean web('https://www.mathworks.com') instead of web(linkstring)?

[Cris LaPierre]

No, you can pass the url in using a variable. See this example.

I mean 'false' instead of false, but as I stated, I don't see the 'UniformOutput' name-value pair documented for web or weboptions, so I'm not sure you need it at all.

[Fangjun Jiang]

Wow, that is surprising. Thanks!

[Johannes]

Thank ypu for your answer. I tried the code without UniformOutput in a Test script using the mathworks-URL and it worked. So it must be something about the string I am trying to import from Excel. However, if I call the right cell from the table, the TextType does not make it a string. It`s still a 1x1 table.

[Johannes]

I have just found my error. The find function does not return anything, so the table is empty. This is because my input field is a text field and the numbers compared in the Excel file are doubles. Str2double fixed the issue.

filling_code = str2double(app.SearchforfillingcodeEditField.Value);
r_1 = ismember(app.codeguide.('Filling Code'),filling_code);                                              %Ermittlung der richtigen Reihe nach Eingabe
row = find(r_1);
linkstring = app.links(row,:);
linkstring = linkstring{1,1};
web(linkstring)