add comments,and remove unused library.

Change-Id: I55c422205f7225a17e0a3e74209c4cecae4e5006
Signed-off-by: Sharl <amoiz.shine@gmail.com>
27 bugs fixed.

Change-Id: Ie4ff09bcf4a5360894afdb064aa44d60e13e8be0
Signed-off-by: Sharl <amoiz.shine@gmail.com>