package com.example.animation;
import android.support.v4.view.ViewPager;
import android.view.View;
public class DepthPageTransformer implements ViewPager.PageTransformer
{
private static final float MIN_SCALE = 0.75F;
@Override
public void transformPage(View view, float position)
{
int pageWidth = view.getWidth();
if(position < -1)
{
// [-Infinity,-1)
// this page is way off-screen to the left
view.setAlpha(0);
}
else if(position <= 0)
{
// [-1,0]
// use the default slide transition when moving to the left page
view.setAlpha(1);
view.setTranslationX(0);
view.setScaleX(1);
view.setScaleY(1);
}
else if(position <= 1)
{
// (0,1]
// fade the page out
view.setAlpha(1 - position);
// counteract the default slide transition
view.setTranslationX(pageWidth * -position);
// scale the page down (between MIN_SCALE and 1)
float scaleFactor = MIN_SCALE + (1 - MIN_SCALE) * (1 - Math.abs(position));
view.setScaleX(scaleFactor);
view.setScaleY(scaleFactor);
}
else
{
// (1,+Infinity]
// this page is way off-screen to the right
view.setAlpha(0);
}
}
}