1. Open Existing Android Studio project.2. After opening, Projects---Android inside is empty. At this point, you need to select the Projects-> Project panel, right-click Open Module settings.3. Click on the + sign above settings, then select Android and click OK.
With the above steps, you should be able to find Attach Debugger to Android process below run.
There seems to be no process to choose when debugging, and after attempting to set up the SDK in modules, there are processes that can be attached to it. If the selected SDK does not have source code, when the jump will jump to the version of decompile, if there is source code, will jump to the source code. Reference: http://blog.csdn.net/tuhuolong/article/details/46563739
Http://www.cnblogs.com/Lefter/p/4176991.html
"Original" How to debug native Android framework-level source code under Android Studio