How to add error message to opportunity record page

Question

I have added a custom button on the Opportunity page which invokes an apex code. The invoked apex code is redirecting to the same Opportunity page.

    ...
    PageReference pg = new PageReference('/'+ oppId +'?test=true'); 
    pg.setRedirect(true);        
    return pg;

I would like to add error message after the redirect to the Opportunity page.

Please advise how this can be achieved?

Answer 1

You cannot do both at the same time, either you want to redirect or you want to show an error.

I would suggest you:

1. Create a variable to store the message you want to show
2. On the VF page rerender the sections after the action that currently causes the redirect
3. Render sections based on the message being present
4. In the section that displays the message provide a button for the user to go back to the opportunity
5. on click of the button the current page reference gets executed.

You could also add a timer on display of the message to have it redirect to the opportunity automatically.

Unfortunately, you do not provide enough information in your question to provide a more detailed response.