Carousel Layout

MainActivity.java

package catvinhquang.androiddeveloper;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.DisplayMetrics;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.ImageView;

public class MainActivity extends Activity {
    public final static float SCALE = 0.7f;
    public final static float DIFF_SCALE = 1 - SCALE;

    private int screenWidth;
    private int screenHeight;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        DisplayMetrics dm = getResources().getDisplayMetrics();
        screenWidth = dm.widthPixels;
        screenHeight = dm.heightPixels;

        final ViewPager root = new ViewPager(this);
        root.setPageMargin(-screenWidth / 2);
        root.setOffscreenPageLimit(3);
        root.setAdapter(new PhotoAdapter());
        root.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
                if (positionOffset >= 0f && positionOffset <= 1f) {
                    View cur = root.findViewById(position);
                    View next = root.findViewById(position + 1);

                    if (cur != null && next != null) {
                        cur.setScaleX(1 - DIFF_SCALE * positionOffset);
                        cur.setScaleY(1 - DIFF_SCALE * positionOffset);
                        next.setScaleX(SCALE + DIFF_SCALE * positionOffset);
                        next.setScaleY(SCALE + DIFF_SCALE * positionOffset);
                    }
                }
            }

            @Override
            public void onPageSelected(int position) {
            }

            @Override
            public void onPageScrollStateChanged(int state) {
            }
        });

        setContentView(root);
    }

    class PhotoAdapter extends PagerAdapter {
        private int[] images = new int[]{R.drawable.image1, R.drawable.image2,
                R.drawable.image3, R.drawable.image4,
                R.drawable.image5, R.drawable.image6,
                R.drawable.image7, R.drawable.image8,
                R.drawable.image9, R.drawable.image10};

        @NonNull
        @Override
        public Object instantiateItem(@NonNull ViewGroup container, int position) {
            Context c = container.getContext();

            FrameLayout root = new FrameLayout(c);
            root.setId(position);
            root.setScaleX(MainActivity.SCALE);
            root.setScaleY(MainActivity.SCALE);

            ImageView iv = new ImageView(c);
            FrameLayout.LayoutParams lp = new FrameLayout.LayoutParams(screenWidth / 2, screenHeight / 2);
            lp.gravity = Gravity.CENTER;
            iv.setLayoutParams(lp);
            iv.setImageResource(images[position]);
            root.addView(iv);

            container.addView(root);
            return root;
        }

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

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

        @Override
        public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
            container.removeView((View) object);
        }
    }
}