How to handle data from an external program on Mac OSx

I would like to make a program (I would prefer in C language) , but even in cocoa , that can take data from an exter开发者_高级运维nal program (such as iTunes or adium) and will use them. For example i would like to take the data of a listbox or the text of the chat so as to manipulate it. I need a place to start. In windows I think it is possible with some apis that find the hWnd of a window and then find a pointer to the listbox or textbox. Please give me some info on how to start. Thanks you in advance.

It's not clear exactly what you want to do. It's either impossible or severely restricted.

For one thing, different applications use different ways of constructing a “listbox”—Cocoa applications use NSTableView, Carbon applications use DataBrowser, and GTK, Qt, and Java applications use even more different APIs. These do not all go through some common kind of list box thingy; each is an independent implementation.

(You could hope that either NSTableView or DataBrowser would be based on the other, but don't count on it.)

For another, it is impossible to obtain a pointer to that control. You cannot access another application's NSTableView or DataBrowser view or GTK/Qt/Java equivalent unless (and this only works for NSTableView) that application deliberately serves it up to you. It doesn't sound like that's your situation.

The closest you can get to that is Accessibility, which may be pretty close, but is unlikely to work with most applications not based on Cocoa.

Even then, the view may not be showing you all the data. A table view may be lazily populated, and a table view designed in imitation of the iOS UITableView may even never have all the data (because it only has what it can show).

(All of the above applies to every kind of view, not just table views. Collection views, text fields, buttons—same deal for all of them.)

The only way to get at the true, complete copy of the data is to ask the controller that owns it. And, again, that's impossible if the application is not specifically offering it to you. Not to mention, the application might not even have a controller (not object-oriented, not MVC, or just sloppily made).

… so as to manipulate it.

Getting the data in the first place is the easy part. It is nigh-impossible to mess with data in another application—for good reason.

The closest you're going to get to either of these goals is the Accessibility interfaces.