Custom SeekBar Drawable Android

Custom SeekBar Drawable Android

I want to personalised the default android seekbar to:

I read about nine patch image and create 6 png images :
the first 3 is for the gray progress bar (progressDrawable) as shown below:
right image

2.center

left

the result of these should be

The blue images represent the progress and are as follows:
right

left

and the thumb is as follows:

My question is how can i use nine patch image to generate the custom
seekbar exactly as first picture and also how can i apply this to my
seekbar.