Animating Drawer Toggle

AnimatingDrawerToggle.java

public class AnimatingDrawerToggle extends ActionBarDrawerToggle {

    public enum State {
        UP,
        HOME
    }

    private static final float MENU_POSITION = 0f;
    private static final float ARROW_POSITION = 1.0f;

    private final int duration;
    private final DrawerLayout drawerLayout;
    private final Activity activity;
    private State currentState;

    public AnimatingDrawerToggle(Activity activity, DrawerLayout drawerLayout, Toolbar toolbar, int openDrawerContentDescriptionResource, int closeDrawerContentDescriptionResource) {
        super(activity, drawerLayout, toolbar, openDrawerContentDescriptionResource, closeDrawerContentDescriptionResource);
        duration = activity.getResources().getInteger(android.R.integer.config_shortAnimTime);
        this.drawerLayout = drawerLayout;
        this.activity = activity;
        currentState = State.HOME;
    }

    public void animateToUp() {
        if (currentState != State.UP) {
            ValueAnimator anim = ValueAnimator.ofFloat(MENU_POSITION, ARROW_POSITION);
            anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                @Override
                public void onAnimationUpdate(ValueAnimator valueAnimator) {
                    float slideOffset = (Float) valueAnimator.getAnimatedValue();
                    onDrawerSlide(drawerLayout, slideOffset);
                }
            });

            anim.setInterpolator(new DecelerateInterpolator());
            anim.setDuration(duration);
            anim.start();

            currentState = State.UP;
        }
    }

    public void animateToHome() {
        if (currentState != State.HOME) {
            ValueAnimator anim = ValueAnimator.ofFloat(ARROW_POSITION, MENU_POSITION);
            anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                @Override
                public void onAnimationUpdate(ValueAnimator valueAnimator) {
                    float slideOffset = (Float) valueAnimator.getAnimatedValue();
                    onDrawerSlide(drawerLayout, slideOffset);
                }
            });

            anim.setInterpolator(new DecelerateInterpolator());
            anim.setDuration(duration);
            anim.start();
            currentState = State.HOME;
        }
    }

    public State getCurrentState() {
        return currentState;
    }
}