Regarding seekbar drawables

Question

i actually used that <clip> to set the drawables for the seekbar as :

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android"&gt;

<item android:id="@+android:id/background" android:drawable="@drawable/progbar2" />

<item android:id="@+android:id/SecondaryProgress">
<clip android:drawable="@drawable/progbar3" />
</item>
<item android:id="@+android:id/progress">
<clip android:drawable="@drawable/progbar1"/>
</item>

</layer-list>

bt while setting the progress using the fns incrementProgressBy() and incrementSecondaryProgressBy() i get weired behavior...as the secondary progress gets incremented...the progresss also gets upto tht mark...i.e...it also gets drawn (on secondary progress)... can u help?