viewpager實現畫廊(中間圖片全部顯示，左右顯示一部分b佈局)無限輪播效果

1.佈局

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="10dp"
    android:background="#FFFFFF"
    android:clipChildren="false"
    android:gravity="center_horizontal"
    android:layerType="software"
    android:orientation="vertical">
    <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>

2.代碼

MainActivity

import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.ViewGroup;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private ViewPager vp;
    List<Integer> list = new ArrayList<>();

    @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;
        }
        list.add(R.mipmap.a);
        list.add(R.mipmap.b);
        list.add(R.mipmap.c);
        list.add(R.mipmap.d);
        vp.setLayoutParams(lp);
//setPageMargin表示設置圖片之間的間距
        vp.setPageMargin(getResources().getDimensionPixelSize(R.dimen.activity_horizontal_margin));
        vp.setPageTransformer(true, new MyGallyPageTransformer());
        vp.setAdapter(new MyViewpagerAdapter(list, MainActivity.this));
        vp.setCurrentItem(2000);
    }
}

MyGallyPageTransformer

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);
        }
    }
}

MyViewpagerAdapter

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

import java.util.List;


public class MyViewpagerAdapter extends PagerAdapter {

    private List<Integer> list;
    private Context context;
    private int xinWidth;
    private int xinHeight;

    public MyViewpagerAdapter(List<Integer> list, Context context) {
        this.context = context;
        this.list = list;
    }

    @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);
        vp_iv.setImageResource(list.get(position%list.size()));
        container.addView(vp_iv);
        return vp_iv;
    }

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