新建工程时提示Android could not find folder 'tools'，解决方法是：
There is a 'Preferences' dialogbox under Windows menu in eclipse IDE where one can set the SDK path.
1. Select Window > Preferences... to open the Preferences panel.
2. Select Android from the left panel.
3. For the SDK Location in the main panel, press Browse... and find the SDK root directory.
4. Press Apply, then OK.
（一进去直接就点左边android的分支，别忘了点android。。。） （引用）