问题
Is it possible to make a call from application with out quitting application in iOS 4?
回答1:
You will have to have your application remember its state. That way it can be resumed when launched again. Even with the new multitasking your suspended apps may be forcibly quit if the device needs more memory.
Apple has a guide named "Supporting Multitasking In Your Applications" which you should be able to locate.
Related SO: Does iOS 4 make “Real Multitasking” available to 3rd party developers?
However, you may not replicate core OS functionality so this is the only way to get what you want.
来源：https://stackoverflow.com/questions/3957043/make-a-call-from-iphone-application-without-quitting