<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:gravity="center"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:clipToPadding="false" />
</LinearLayout>

private const float MIN_SCALE = 0.85f;
private const float MIN_ALPHA = 0.5f;
public void TransformPage(View page, float position)
{
int pageWidth = page.Width;
int pageHeight = page.Height;

if (position < -1)
{
    // [-Infinity,-1)
    // This page is way off-screen to the left.
    page.Alpha = 0;
    Console.WriteLine("1.Position: " + position);
}
else if (position <= 1)
{
    // [-1,1]
    // Modify the default slide transition to shrink the page as well
    float scaleFactor = Math.Max(MIN_SCALE, 1 - Math.Abs(position));
    float vertMargin = pageHeight * (1 - scaleFactor) / 2;
    float horzMargin = pageWidth * (1 - scaleFactor) / 2;
    if (position < 0)
    {
        page.TranslationX = (horzMargin - vertMargin / 2);
    }
    else {
        page.TranslationX = (-horzMargin + vertMargin / 2);
    }

    // Scale the page down (between MIN_SCALE and 1)
    page.ScaleX=(scaleFactor);
    page.ScaleY=(scaleFactor);

    // Fade the page relative to its size.
    page.Alpha = (MIN_ALPHA + (scaleFactor - MIN_SCALE) / (1 - MIN_SCALE) * (1 - MIN_ALPHA));
    Console.WriteLine("2.Position: " + position);
}
else {
    // (1,+Infinity]
    // This page is way off-screen to the right.
    page.Alpha = 0;
    Console.WriteLine("3.Position: " + position);
}
}