提示：Android ADT error, dx.jar was not loaded from the SDK folder

升级以后，DEBUG或者生成apk时，提示dx.jar was not loaded from the SDK folder。网络上试了N种办法没有解决，

最后，在https://stackoverflow.com/questions/5228453/android-adt-error-dx-jar-was-not-loaded-from-the-sdk-folder中，solution倒没有解决，但其中，第24条回答中提示：

I just encountered the same problem yesterday, in Eclipse of Neon Release (4.6.0).

It's a compatible issue related to 26.0.0 of android-sdk "build-tools".

Simple Solution:

• Delete "26.0.0" in "build-tools" directory
• Use "25.0.2" instead
• Restart eclipse

Other Solution:

• add this in the project.properties of your project:
  sdk.buildtools=25.0.2

Good luck!

于是，我在project.properties中，增加一句sdk.buildtools=25.0.3

即解决问题（前提是sdk\build-tools目录下是有25.0.3）