从iPhone应用程序拨打电话而无需退出
在iOS 4中是否可以在不退出应用程序的情况下从应用程序拨打电话?
Is it possible to make a call from application with out quitting application in iOS 4?
您将必须让您的应用程序记住其状态.这样，当再次启动它时可以将其恢复.即使使用了新的 multitasking ，如果设备需要更多内存，您仍可能会强行退出已暂停的应用.
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有一个名为在应用程序中支持多任务"的指南，您应该可以找到它.
Apple has a guide named "Supporting Multitasking In Your Applications" which you should be able to locate.
相关信息: iOS 4是否使真正的多任务处理"可供第三方开发人员使用?
但是，您可能无法复制核心操作系统功能，因此这是获得所需功能的唯一方法.
However, you may not replicate core OS functionality so this is the only way to get what you want.