Android实现单页显示3个Item的ViewPager炫酷切换效果

<FrameLayout  android:layout_width="match_parent"  android:layout_height="160dp"  android:clipChildren="false"  android:layout_centerInParent="true"  android:background="#aadc71ff"  >  <android.support.v4.view.ViewPager    android:id="@+id/id_viewpager"    android:layout_width="match_parent"    android:layout_marginLeft="60dp"    android:clipChildren="false"    android:layout_marginRight="60dp"    android:layout_height="120dp"    android:layout_gravity="center"    >  </android.support.v4.view.ViewPager></FrameLayout>

mViewPager.setPageMargin(20);//设置page间间距，自行根据需求设置mViewPager.setOffscreenPageLimit(3);//>=3mViewPager.setAdapter...//写法不变//setPageTransformer 决定动画效果mViewPager.setPageTransformer(true, new RotateDownPageTransformer());

<?xml version="1.0" encoding="utf-8"?><FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:tools="http://schemas.android.com/tools"  android:layout_width="match_parent"  android:layout_height="wrap_content"  android:background="#aadc71ff"  android:clipChildren="false"  tools:context="com.example.administrator.banner2.MainActivity">  <android.support.v4.view.ViewPager    android:id="@+id/viewpager"    android:layout_width="match_parent"    android:layout_height="150dp"    android:layout_gravity="center"    android:layout_marginBottom="10dp"    android:layout_marginLeft="30dp"    android:layout_marginRight="30dp"    android:layout_marginTop="10dp"    android:clipChildren="false"></android.support.v4.view.ViewPager>  <LinearLayout    android:id="@+id/dotLayout"    android:layout_width="match_parent"    android:layout_height="10dp"    android:layout_gravity="bottom"    android:layout_marginBottom="10dp"    android:gravity="center"    android:orientation="horizontal"></LinearLayout></FrameLayout>

import android.os.Bundle;import android.os.Handler;import android.support.v4.view.PagerAdapter;import android.support.v4.view.ViewPager;import android.support.v7.app.AppCompatActivity;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.RelativeLayout;import com.zhy.magicviewpager.transformer.ScaleInTransformer;import java.util.Timer;import java.util.TimerTask;public class MainActivity extends AppCompatActivity {  private ViewPager mViewPager;  private PagerAdapter mAdapter;  private LinearLayout dotLayout;  private Timer timer;  private Handler mHandler = new Handler();  private int prePosition = 0;  int[] imgRes = {R.drawable.a, R.drawable.b, R.drawable.c, R.drawable.d,      R.drawable.e, R.drawable.f, R.drawable.g, R.drawable.h, R.drawable.i};  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    mViewPager = (ViewPager) findViewById(R.id.viewpager);    dotLayout = (LinearLayout) findViewById(R.id.dotLayout);    initDots();    mViewPager.setPageMargin(20);    mViewPager.setOffscreenPageLimit(3);    mViewPager.setAdapter(mAdapter = new PagerAdapter() {      @Override      public Object instantiateItem(ViewGroup container, int position) {        ImageView view = new ImageView(MainActivity.this);        view.setScaleType(ImageView.ScaleType.FIT_XY);        view.setImageResource(imgRes[position % imgRes.length]);        container.addView(view);        return view;      }      @Override      public void destroyItem(ViewGroup container, int position, Object object) {        container.removeView((View) object);      }      @Override      public int getCount() {        return Integer.MAX_VALUE;      }      @Override      public boolean isViewFromObject(View view, Object o) {        return view == o;      }    });    mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {      @Override      public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {      }      @Override      public void onPageSelected(int position) {        dotLayout.getChildAt(prePosition).setEnabled(false);        dotLayout.getChildAt(position % imgRes.length).setEnabled(true);        prePosition = position % imgRes.length;      }      @Override      public void onPageScrollStateChanged(int state) {      }    });    mViewPager.setPageTransformer(true, new ScaleInTransformer());    if (null != timer) {      timer.cancel();    }    timer = new Timer();    timer.schedule(new TimerTask() {      @Override      public void run() {        mHandler.post(new Runnable() {          @Override          public void run() {            mViewPager.setCurrentItem(mViewPager.getCurrentItem() + 1);          }        });      }    }, 0, 1000);  }  private void initDots() {    if (null != dotLayout) {      dotLayout.removeAllViews();    }    for (int i = 0; i < imgRes.length; i++) {      ImageView dot = new ImageView(this);      dot.setEnabled(false);      dot.setImageResource(R.drawable.dot);      LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);      params.leftMargin = 10;      dot.setLayoutParams(params);      dotLayout.addView(dot);    }    dotLayout.getChildAt(0).setEnabled(true);  }}

<?xml version="1.0" encoding="utf-8"?><selector xmlns:android="http://schemas.android.com/apk/res/android">  <item android:state_enabled="true">    <shape android:shape="rectangle">      <size android:width="15dp" android:height="3dp"></size>      <corners android:radius="10dp" />      <solid android:color="#ff0000" />    </shape>  </item>  <item android:state_enabled="false">    <shape android:shape="rectangle">      <size android:width="15dp" android:height="3dp"></size>      <corners android:radius="10dp" />      <solid android:color="#ffffff" />    </shape>  </item></selector>