viewpager的动画

网址：http://android.jobbole.com/81083/

ZoomOutPageTransformer
当在相邻界面滑动时，这个page transformer使页面收缩并褪色。当页面越靠近中心，它将渐渐还原到正常大小并且图像渐入。

Depth Page Transformer
这个page transformer使用默认动画的屏幕左滑动画。但是为右滑使用一种“潜藏”效果的动画。潜藏动画将page淡出，并且线性缩小它。

mPager.setPageTransformer(true, new ZoomOutPageTransformer());

ZoomOutPageTransformer .java 类

package com.zhy.view;

 

import android.annotation.SuppressLint;

import android.support.v4.view.ViewPager;

import android.util.Log;

import android.view.View;

 

public class ZoomOutPageTransformer implements ViewPager.PageTransformer

{

private static final float MIN_SCALE = 0.85f;//该值是滑动时候显示的大小（滑动中）

private static final float MIN_ALPHA = 0.5f;

 

@SuppressLint("NewApi")

public void transformPage(View view, float position)

{

int pageWidth = view.getWidth();

int pageHeight = view.getHeight();

 

Log.e("TAG", view + " , " + position + "");

 

if (position < -1)

{ // [-Infinity,-1)

// This page is way off-screen to the left.

view.setAlpha(0);

 

} else if (position <= 1) //a页滑动至b页 ； a页从 0.0 -1 ；b页从1 ~ 0.0

{ // [-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);

}

}

}