解决办法：
You need to turn off Automatic Reference Counting. You do this by clicking on your project in the navigator (the top item in the finder-like thing on the left), then click on your project, select "Build Settings" and turn off the option "Objective-C Automatic Reference Counting" (you can use the search field on the upper right to search it).
你点击工程名称，右侧的窗口中会出现工程的设置，右侧窗口左侧有两个标签的设置，你选择project的building settings选项，然后再右侧窗口的右半部分就会出现工程的building Settings选项了。