Android 使用viewpager实现画廊式效果（展示图片）

先看一下效果

1.创建一个自定义类 ZoomOutPageTransformer

public class ZoomOutPageTransformer implements ViewPager.PageTransformer {
    //自由控制缩放比例
    private static final float MAX_SCALE = 1f;
    private static final float MIN_SCALE = 0.8f;//0.85f

    @Override
    public void transformPage(View page, float position) {

        if (position <= 1) {

            float scaleFactor = MIN_SCALE + (1 - Math.abs(position)) * (MAX_SCALE - MIN_SCALE);

            page.setScaleX(scaleFactor);

            if (position > 0) {
                page.setTranslationX(-scaleFactor * 2);
            } else if (position < 0) {
                page.setTranslationX(scaleFactor * 2);
            }
            page.setScaleY(scaleFactor);
        } else {

            page.setScaleX(MIN_SCALE);
            page.setScaleY(MIN_SCALE);
        }
    }
}

2.创建适配器  MyAdapter

public class MyAdapter extends PagerAdapter {

    private int[] mData;
    private Context mContext;

    public MyAdapter(Context ctx, int[] data) {
        this.mContext = ctx;
        this.mData = data;
    }

    @Override
    public int getCount() {
        return mData.length;// 返回数据的个数
    }

    @Override
    public Object instantiateItem(final ViewGroup container, final int position) {//子View显示
        View view = View.inflate(container.getContext(), R.layout.item, null);
        ImageView imageView = view.findViewById(R.id.iv_icon);
        imageView.setImageResource(mData[position]);

        imageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(mContext, "当前条目：" + position, Toast.LENGTH_SHORT).show();
            }
        });

        container.addView(view);//添加到父控件
        return view;
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == object;// 过滤和缓存的作用
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        container.removeView((View) object);//从viewpager中移除掉
    }
}

3.item布局

4.activity_main布局

5.Main_Activity

public class MainActivity extends AppCompatActivity {
    private ViewPager mViewPager;
    private LinearLayout ll_layout;

    //向导界面的图片
    private int[] mPics = new int[]{R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.mipmap.ic_launcher};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
    }

    private void initView() {
        mViewPager = (ViewPager) findViewById(R.id.viewPager);
        ll_layout = (LinearLayout) findViewById(R.id.ll_layout);

        //设置适配器
        mViewPager.setAdapter(new MyAdapter(this, mPics));
        mViewPager.setPageMargin(20);
        mViewPager.setOffscreenPageLimit(mPics.length);
        mViewPager.setPageTransformer(true, new ZoomOutPageTransformer());//设置画廊模式

        //左右都有图
        mViewPager.setCurrentItem(1);

        //viewPager左右两边滑动无效的处理
        ll_layout.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View view, MotionEvent motionEvent) {
                return mViewPager.dispatchTouchEvent(motionEvent);
            }
        });
    }
}