1) 添加系统API或者修改@hide的API后，需要执行
make update-api，然后再make
2) 修改公共api后，需要
make update-api
比较framework/base/api 下的current.xml跟原始x.xml(比如2.2为8.xml, 2.3.3为10.xml)，同时修改x.xml
然后make
see build/core/apicheck_msg_current.txt
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You have tried to change the API from what has been previously approved.
To make these errors go away, you have two choices:
1) You can add "@hide" javadoc comments to the methods, etc. listed in the
errors above.
2) You can update current.txt by executing the following command:
make update-api
To submit the revised current.txt to the main Android repository,
you will need approval.
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