Android最简单的轮播图实现

最简单的轮播图

参考http://www.cnblogs.com/xurui1995/p/5759371.html博文

xml布局

<?xml version="1.0" encoding="utf-8"?><RelativeLayout 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"    tools:context="com.example.playpicture.MainActivity">    <RelativeLayout        android:layout_width="match_parent"        android:layout_height="180dp">        <android.support.v4.view.ViewPager            android:id="@+id/vp"            android:layout_width="match_parent"            android:layout_height="match_parent">        </android.support.v4.view.ViewPager>        <LinearLayout            android:layout_width="match_parent"            android:layout_height="30dp"            android:layout_alignParentBottom="true"            android:background="#66000000"            android:orientation="horizontal">            <LinearLayout                android:id="@+id/point_container"                android:layout_width="match_parent"                android:layout_height="wrap_content"                android:layout_gravity="center"                android:gravity="center"                android:orientation="horizontal">            </LinearLayout>        </LinearLayout>    </RelativeLayout></RelativeLayout>

在Drawable下新建下面3个Drawable resource file

bg_shape

<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android"    android:shape="oval">    <corners android:radius="5dp"/>    <solid android:color="#FFFFFF"/></shape>

bg_shape2

<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android"    android:shape="oval">    <corners android:radius="5dp"/>    <solid android:color="#808080"/></shape>

selector

<?xml version="1.0" encoding="utf-8"?><selector xmlns:android="http://schemas.android.com/apk/res/android">    <item android:drawable="@drawable/bg_shape" android:state_enabled="true" />    <item android:drawable="@drawable/bg_shape2" android:state_enabled="false" /></selector>

下面是完整代码：

package com.example.playpicture;import android.os.Bundle;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 java.util.ArrayList;/** * 在Activity中使用页面改变监听实现可以手动滑动的轮播图 */public class MainActivity extends AppCompatActivity implements ViewPager.OnPageChangeListener{    private ViewPager vp;    private  int[] imas;    private LinearLayout ll;    private ArrayList<ImageView> imaList;    private Boolean flag;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //初始化布局        initViews();        //数据        initData();        //适配器        initAdapter();        flag=true;        //实现自动轮播        new Thread(new Runnable() {            @Override            public void run() {                while (flag) {                    try {                        Thread.sleep(2000);                    } catch (InterruptedException e) {                        e.printStackTrace();                    }                    //这里加上MainActivity.this获取当前context环境                    MainActivity.this.runOnUiThread(new Runnable() {                        @Override                        public void run() {                            vp.setCurrentItem(vp.getCurrentItem() + 1);                        }                    });                }            }        }).start();    }    private void initAdapter() {        ll.getChildAt(0).setEnabled(true);        vp.setAdapter(new MyAdapter());        vp.setCurrentItem(Integer.MAX_VALUE/2+2);//这里以一个%5为0的数开始，这样打开默认会在第0个item显示    }    @Override    protected void onDestroy() {        super.onDestroy();        flag=false;    }    private void initData() {    }    private void initViews() {        vp = (ViewPager) findViewById(R.id.vp);        vp.setOnPageChangeListener(this);        ll= (LinearLayout) findViewById(R.id.point_container);        //图片数组，将要实现轮播的图片放这数组里        imas = new int[]{R.drawable.pic1, R.drawable.pic2, R.drawable.pic3, R.drawable.pic4, R.drawable.pic5,};        ImageView iv;        imaList = new ArrayList<ImageView>();        View pointview;        for (int i = 0; i < imas.length; i++) {            iv = new ImageView(this);            iv.setImageResource(imas[i]);            imaList.add(iv);            //加小白点            pointview =new View(this);            pointview.setEnabled(false);            pointview.setBackgroundResource(R.drawable.selector);            LinearLayout.LayoutParams params =new LinearLayout.LayoutParams(15,15);            //params.gravity= Gravity.CENTER;            if(i!=0)                params.leftMargin=10;            ll.addView(pointview,                    params );        }    }    @Override    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {    }    @Override    public void onPageSelected(int position) {        for(int i=0;i<ll.getChildCount();i++){            ll.getChildAt(i).setEnabled(false);        }        ll.getChildAt(position%5).setEnabled(true);//设置小白点    }    @Override    public void onPageScrollStateChanged(int state) {    }    class MyAdapter extends PagerAdapter {        @Override        public Object instantiateItem(ViewGroup container, int position) {            int newposition =position%5;//得到新位置            ImageView imageView=imaList.get(newposition);            container.addView(imageView);            return imageView;//把View对象返回给框架，必须重写        }        @Override        public void destroyItem(ViewGroup container, int position, Object object) {            container.removeView((View) object);        }        @Override        public int getCount() {            return Integer.MAX_VALUE;        }        @Override //判断复用        public boolean isViewFromObject(View view, Object object) {            return view==object;        }    }}

这就是最简单的轮播图实现（经测试）