iOS文档说明，当应用进入后台时，某些事情应该发生，以避免应用回到前台时产生混淆。其中之一就是取消UIActionSheet's和UIAlertView's。
这个项目就是自动完成这些。另外，我还添加了一些具有块而不是代理的初始化方法。
要将库包含到您自己的项目中，只需将静态库拖拽到您项目中的一个合理位置。Xcode会做剩下的工作。该项目还包含一个微型的示例项目。
/*
* Copyright 2012 Stephen Darlington, Wandle Software Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://apache.ac.cn/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/