Can an iPad app directly launch another app?

I was wondering if it was possible to launch an iPad app directly from within another app. For example, could I write a login page that takes you too a desktop type page where you can select an app to run, and then launch that app as say, a开发者_C百科 new thread? I am not sure this is possible, I am just curious about the capabilities of the new iOS multitasking features. Thanks!

---

It depends on the app you wish to launch. Some of them register URLs that let you launch links like itunes:// and the like. Check this out: http://developer.apple.com/iphone/library/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/StandardBehaviors/StandardBehaviors.html#//apple_ref/doc/uid/TP40007072-CH4-SW7

The important section is the one entitled "Implementing Custom URL Schemes".

EDIT: Here's a link to a website that catalogs the various URLs for existing apps: http://handleopenurl.com/.

---

Can you use custom url schemes to launch other apps

http://www.idev101.com/code/Objective-C/custom_url_schemes.html

---

There's a directory of existing URL registrations at HandleOpenURL that might come in handy here too.