Then I turn to procmon for help.
First, I start eclipse. Then, run procmon and add a filter of process name equals eclipse.exe. After I captured the file system activities when I tried to view a android framework class's declaration which ends in not finding the corresponding file. I noticed there is a failure on the following path: android_sdk_installation_
So, the solution is:
1. Create a sources folder in android_sdk_installation_
2. Copy everything in android_1.5_cupcake_src\
It's very likely that Eric is using an older version of android sdk which has different file structure from my android sdk 1.6r1. Though his blog isn't totally accurate for current version, I still want to thank him for showing me the right way to go with his smartness.
The step 2 isn't a good way to organize java file because it only put framework's source code in place. The best tool I'm aware of is this python script by Damon Kohle. He improved the one provided by Michael and it will adjust the source code organization to fit eclipse's needs.