android-viewpager

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

package viewpager.sunfan.viewpager;

import android.app.Activity;
import android.os.Bundle;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

import java.util.LinkedList;
import java.util.List;

public class MainActivity extends Activity {

    int[] mImgIds = new int[]{R.drawable.img1,R.drawable.img2,R.drawable.img3};
    List<ImageView> mImageViews = new LinkedList<ImageView>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ViewPager mViewPager = (ViewPager) findViewById(R.id.view_pager);
        mViewPager.setPageTransformer(true,new ZoomOutPageTransformer());
        mViewPager.setAdapter(new PagerAdapter() {
            @Override
            public Object instantiateItem(ViewGroup container, int position) {
                ImageView imageView = new ImageView(MainActivity.this);
                imageView.setImageResource(mImgIds[position]);
                imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
                container.addView(imageView);
                mImageViews.add(imageView);
                return imageView;
            }

            @Override
            public void destroyItem(ViewGroup container, int position, Object object) {
                container.removeView(mImageViews.get(position));

            }

            @Override
            public int getCount() {
                return mImgIds.length;
            }

            @Override
            public boolean isViewFromObject(View view, Object object) {
                return view==object;
            }
        });

    }
}

package viewpager.sunfan.viewpager;

import android.support.v4.view.ViewPager;
import android.view.View;

/**
 * Created by sunfan on 15-4-17.
 */
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);
        }
    }
}