Android广告轮播图实现

来源：互联网发布：如何参加淘宝客编辑：程序博客网时间：2024/04/30 10:36

第一步，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="match_parent"    tools:context="com.example.xw.myviewpager.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_alignParentBottom="true"        android:orientation="horizontal"        android:background="#66000000"        android:layout_height="30dp">        <LinearLayout            android:id="@+id/point_container"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:orientation="horizontal"            android:layout_gravity="center"            android:gravity="center"           >        </LinearLayout>    </LinearLayout></RelativeLayout></RelativeLayout>

这里的point_container用来做小圆点的容器

二圆点形状和状态选择器

bg_shape.xml

<?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

<?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

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

enable="false"是灰色圆点，当state_enabled="true"是白色圆点
三 MainActivity

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;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();                        }                        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        imas = new int[]{R.drawable.a, R.drawable.b, R.drawable.c, R.drawable.d, R.drawable.e,};        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;        }    }}

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