使用ViewPager实现屏幕滑动效果

oncreate中设置viewPager
 
        viewPager.setPageTransformer(true,new DepthPageTransformer());//设置页面过滤动画效果
        pagerAdapter = new ScreenSlidePagerAdapter(getSupportFragmentManager());//获得页面适配的适配器
        viewPager.setAdapter(pagerAdapter);//设置适配器

创建一个适配器
 
    private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {
        public ScreenSlidePagerAdapter(FragmentManager fm) {
            super(fm);
        }
        @Override
        public Fragment getItem(int position) {
            return new ScreenSlidePageFragment();
        }
        @Override
        public int getCount() {
            return NUM_PAGES;
        }
    }

新建一个Frament装载内容

public class ScreenSlidePageFragment extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState) {
        ViewGroup rootView = (ViewGroup) inflater.inflate(
                R.layout.activity_main, container, false);
        return rootView;
    }
}

Frament的 xml文件：（只显示一些文本）

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/content"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
 
    <TextView style="?android:textAppearanceMedium"
        android:padding="16dp"
        android:lineSpacingMultiplier="1.2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/lorem_ipsum" />
</ScrollView>

Activity中的xml文件：（就是一个viewPager）

<android.support.v4.view.ViewPager
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/pager"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

下面给出两种过滤动画效果：

1.新页面覆盖旧页面：

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) {
            //这一页是屏幕左边。
            view.setAlpha(0);
 
        } else if (position <= 0) { // [-1,0]
            // 使用默认的幻灯片过渡当向左移动页面
            view.setAlpha(1);
            view.setTranslationX(0);
            view.setScaleX(1);
            view.setScaleY(1);
 
        } else if (position <= 1) { // (0,1]
            // 褪色的页面
            view.setAlpha(1 - position);
 
            // 抵消默认幻灯片过渡
            view.setTranslationX(pageWidth * -position);
 
            float scaleFactor = MIN_SCALE + (1 - MIN_SCALE) * (1 - Math.abs(position));
            view.setScaleX(scaleFactor);
            view.setScaleY(scaleFactor);
 
        } else { // (1,+Infinity]
            view.setAlpha(0);
        }
    }
}

2.缩小页面过滤效果翻页

public class ZoomOutPageTransformer implements ViewPager.PageTransformer {
    private static final float MIN_SCALE = 0.85f;
    private static final float MIN_ALPHA = 0.5f;
    @Override
    public void transformPage(View view, float position) {
        int viewPagerWidth = view.getWidth();
        int viewPagerHight = view.getHeight();
        if (position < -1){
            view.setAlpha(0f);
        } else if (position <= 1){
            float scaleFactor = Math.max(MIN_SCALE,1 - Math.abs(position));
            float vertMargin = viewPagerHight * (1 - scaleFactor) / 2;
            float horzMargin = viewPagerWidth * (1 - scaleFactor) / 2;
            if (position < 0){
                view.setTranslationX(horzMargin - vertMargin / 2);
            }else {
                view.setTranslationX(-horzMargin + vertMargin / 2);
            }
            view.setScaleX(scaleFactor);
            view.setScaleY(scaleFactor);
            view.setAlpha(MIN_ALPHA + (scaleFactor - MIN_SCALE) / (1 - MIN_SCALE) * (1 - MIN_ALPHA));
        } else {
            view.setAlpha(0);
        }
    }
}