错误解决：release' is unavailable: not available in automatic reference counting mode

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。