leftmargin 애니메이션

    final int pos = position;

    Animation ani = new Animation()

    {

      @Override protected void applyTransformation(float interpolatedTime, Transformation t)

      {

        int iPagerPageCount = (int)Math.round(Math.ceil((aryGroupIdx.size()*1.0)/(4*1.0)));

        int iDeviceWidth = lib_device.getDeviceWidth(photo_send2_activity.this);

        int iWidth = iDeviceWidth - lib_common.getPixelValueOfDp(photo_send2_activity.this, 20);

        ((LinearLayout.LayoutParams)ivScroll.getLayoutParams()).leftMargin = pos * (iWidth / iPagerPageCount);

        ((LinearLayout.LayoutParams)ivScroll.getLayoutParams()).width = iWidth / iPagerPageCount;

        ivScroll.requestLayout();

      }

    };

    ani.setDuration(2000);

    ivScroll.startAnimation(ani);

참고 : http://stackoverflow.com/questions/13881419/android-change-left-margin-using-animation
이렇게 했는데, 애니메이션 안된다.
아래처럼 하면 애니메이션 잘 된다.

int iPagerPageCount = (int)Math.round(Math.ceil((aryGroupIdx.size()*1.0)/(4*1.0)));

int iDeviceWidth = lib_device.getDeviceWidth(photo_send2_activity.this);

int iWidth = iDeviceWidth - lib_common.getPixelValueOfDp(photo_send2_activity.this, 20);

int iLeftMargin = position * (iWidth / iPagerPageCount);

final LinearLayout.LayoutParams layoutParams = (LinearLayout.LayoutParams)ivScroll.getLayoutParams();

layoutParams.width = iWidth / iPagerPageCount;

ValueAnimator ani = ValueAnimator.ofInt(layoutParams.leftMargin, iLeftMargin);

ani.addUpdateListener(new ValueAnimator.AnimatorUpdateListener()

{

  @Override public void onAnimationUpdate(ValueAnimator valueAnimator)

  {

    layoutParams.leftMargin = (Integer)valueAnimator.getAnimatedValue();

    ivScroll.requestLayout();

  }

});

ani.setDuration(200);

ani.start();