Created
March 8, 2014 01:26
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ZoomOutPageTransformer
From http://developer.android.com/training/animation/screen-slide.html
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public class ZoomOutPageTransformer implements ViewPager.PageTransformer { | |
private static final float MIN_SCALE = 0.85f; | |
private static final float MIN_ALPHA = 0.5f; | |
public void transformPage(View view, float position) { | |
int pageWidth = view.getWidth(); | |
int pageHeight = view.getHeight(); | |
if (position < -1) { // [-Infinity,-1) | |
// This page is way off-screen to the left. | |
view.setAlpha(0); | |
} 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) { | |
view.setTranslationX(horzMargin - vertMargin / 2); | |
} else { | |
view.setTranslationX(-horzMargin + vertMargin / 2); | |
} | |
// Scale the page down (between MIN_SCALE and 1) | |
view.setScaleX(scaleFactor); | |
view.setScaleY(scaleFactor); | |
// Fade the page relative to its size. | |
view.setAlpha(MIN_ALPHA + | |
(scaleFactor - MIN_SCALE) / | |
(1 - MIN_SCALE) * (1 - MIN_ALPHA)); | |
} else { // (1,+Infinity] | |
// This page is way off-screen to the right. | |
view.setAlpha(0); | |
} | |
} | |
} |
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