Drawable.setState() How do I control the specific state of the drawable?

I have a drawable like this:

<selector xmlns:android="http://schemas.android.com/apk/res/android">

<item android:state_pressed="true"
      android:state_window_focused="true"
      android:drawable="@drawable/seek_thumb_pressed" />

<item android:state_focused="true"
      android:state_window_focused="true"
      android:drawable="@drawable/seek_thumb_selected" />

<item android:state_selected="true"
      android:state_window_focused="true"
      android:drawable="@drawable/seek_thumb_selected" />

<item android:drawable="@drawable/seek_thumb_normal" />

In code, how do I set my Drawable's specific state? I'd like to set it to the state_pressed=true state.