viewpager实现画廊(中间图片全部显示，左右显示一部分b布局)无限轮播效果

一、布局

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:layout_marginTop="10dp"
    android:gravity="center_horizontal"
    android:background="#FFFFFF"
    android:clipChildren="false"
    android:layerType="software"
    >

<android.support.v4.view.ViewPager
    android:id="@+id/vp"
    android:layout_width="300dp"
    android:layout_height="220dp"
    android:layout_gravity="center"
    android:clipChildren="false"
    >

android.support.v4.view.ViewPager>

LinearLayout>

发现上面的RelativeLayout(可以用其它layout替换)和ViewPager的android:clipChildren都设置为了false。

android:clipChildren表示是否限制子View在其范围内，在animations动画以及本文的情况下可以发挥很大的作用。默认为true。

二、适配器

import android.content.Context;
import android.support.v4.view.PagerAdapter;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

import com.baway.chilijie.bean.Data;
import com.bumptech.glide.Glide;

import java.util.List;

/**
 * Created by MacBook- on 2017/4/13.
 */
public class MyViewpagerAdapter extends PagerAdapter {
    private List myInfoLists;
    private Context context;
    private int xinWidth;
    private int xinHeight;

    public MyViewpagerAdapter(List myInfoLists, Context context) {
       this.context=context;
        this.myInfoLists=myInfoLists;
    }

    @Override
    public int getCount() {
        return Integer.MAX_VALUE;
    }

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

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        ImageView vp_iv= new ImageView(context);
        Glide.with(context).load(myInfoLists.get(position%myInfoLists.size()).getActivityImg()).into(vp_iv);
        container.addView(vp_iv);
        return vp_iv;
    }

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

三、自定义 PageTransformer类

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

/**
 * Created by MacBook- on 2017/4/14.
 */
public class MyGallyPageTransformer implements ViewPager.PageTransformer {
    private static final float min_scale = 0.85f;
    @Override
    public void transformPage(View page, float position) {
        float scaleFactor = Math.max(min_scale, 1 - Math.abs(position));
        if (position < -1) {
            page.setScaleX(scaleFactor);
            page.setScaleY(scaleFactor);
        } else if (position < 0) {
            page.setScaleX(scaleFactor);
            page.setScaleY(scaleFactor);
        } else if (position >= 0 && position < 1) {
            page.setScaleX(scaleFactor);
            page.setScaleY(scaleFactor);
        } else if (position >= 1) {
            page.setScaleX(scaleFactor);
            page.setScaleY(scaleFactor);
        }
    }
}

四、Activity

public class MainActivity extends AppCompatActivity{

private ViewPager vp;

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

vp = (ViewPager) findViewById(R.id.vp);

vp.setOffscreenPageLimit(3);
int pagerWidth = (int) (getResources().getDisplayMetrics().widthPixels * 3.0f / 5.0f);
ViewGroup.LayoutParams lp = vp.getLayoutParams();
if (lp == null) {
    lp = new ViewGroup.LayoutParams(pagerWidth, ViewGroup.LayoutParams.MATCH_PARENT);
} else {
    lp.width = pagerWidth;
}
vp.setLayoutParams(lp);
//setPageMargin表示设置图片之间的间距
vp.setPageMargin(getResources().getDimensionPixelSize(R.dimen.activity_horizontal_margin));
vp.setPageTransformer(true,new MyGallyPageTransformer());
vp.setAdapter(new MyViewpagerAdapter(data.getActivityInfo().getActivityInfoList(),getActivity()));
vp.setCurrentItem(2000);

} }