ios打包报错 command line tools instance

You may not have the required environment or OS to build this project
xcode-select: error: tool 'xcodebuild' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance
 at org.apache.tools.ant.taskdefs.ExecTask.runExecute(ExecTask.java:643)

解决方法：
在xcode的Xcode—Preferences—-Location—–Command Line Tool配置一下，不能为空