I use a SeekBar in my application and I would like to customize it a little bit. I already figured out how to change the Drawable for the thumb and
I'm not sure about Seekbars, but Progressbars can be customized by using a custom style (defined in your styles.xml) like so:
Then you can set up a custom drawable based on the android system's progress_horizontal.xml (it's in the frameworks/base/core/res/drawable folder of an AOSP checkout). Here's an example from an open-source project.