iOS4的多任务下支持的内容

iOS4的多任务只是支持下面几个：

Background audio

Voice over IP

Background location

Push notifications

Local notifications

Task finishing- If your app is in mid-task when your customer leaves it, the app can now keep running to finish the task.

Fast app switching- All developers should take advantage of fast app switching, which allows users to leave your app and come right back to where they were when they left - no more having to reload the app.

用的时候还需要在plist文件里面设置一下 找到Required background modes这个选项就能看到需要设置哪些东西了，

有这么三个：App plays audio、App registers for location updates、App provides Voice over IP services。

notifications是不需要设置的。

后台播放好像还有个时间限制，大概是10分钟，10分钟如果还没执行完，系统就是自动结束程序。

苹果的多任务还是限制很多的。