導入項目錯誤（三）v7包報錯：Unable to resolve target ‘android-xxx’

解決方式：
步驟1：
1、仔細看錯誤、分析錯誤

2、可以把主要錯誤信息，依次複製出來分析


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’

步驟2：
sdk版本問題，那就對應當前sdk版本