Hello I have about 10 string messages that I want displayed on screen, but the problem is that they are too long, so I find it clumsy to edit them.
Is there a way to store all these messages in a resource file so that I can edit it easily and also use this resource file to show my 10 messages in my AS3 project? (I keep them in plain *.as file)
How do people do such thing when developing games for example?
It seems that you are just looking for editor with word wrap option enabled.
There are plenty of them. You can use Notepad++, for example, if you want to get word wrapping coupled with syntax highlighting.
And you definitely shall follow RIAstar's link - resource bundles provide you with a possibility to have all your strings in one simple file, to have different strings for different languages without changing your code, to build and to load resources independently from main app.
And by the way, when you press enter inside a quoted string literal, IDE adds + and " signs automatically. Did you know this feature?