导入项目错误（三）v7包报错：Unable to resolve target ‘android-xxx’

解决方式：
步骤1：
1、仔细看错误、分析错误

2、可以把主要错误信息，依次复制出来分析


The project was not built since its build path is incomplete. Cannot find the class file for java.lang.Object. Fix the build path then try building this project
The type java.lang.Object cannot be resolved. It is indirectly referenced from required .class files
Unable to resolve target ‘android-16’

步骤2：
sdk版本问题，那就对应当前sdk版本