NSCondition , 多线程 同步 例子 运用于某个线程要等待若干个线程完成后再开始执行的情境， iphone的多线程开发是比较困难的地方-NSCondition, an example applied to a multi-thread synchronization thread to wait several months to complete before starting the implementation of the thread contexts, iphone m

实现客户服务端同步待办事项，可对待办事项进行增删改查、上传、下载等操作。-Synchronization to achieve customer service side do, can do for CRUD, upload, download and other operations.

模仿，网络同步获得数据的等待提示框，右透明效果！-Imitation, network synchronization wait for the prompt box to get the data, the right transparency effects!