广告轮播2

1、权限

<uses-permission android:name="android.permission.INTERNET"/>

2、视图

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical"
 6     >
 7     <android.support.v4.view.ViewPager
 8         android:id="@+id/vp"
 9         android:layout_width="match_parent"
10         android:layout_height="match_parent"
11         android:layout_weight="1"
12         >   
13     </android.support.v4.view.ViewPager>
14    
15     <LinearLayout 
16         android:layout_width="wrap_content"
17         android:layout_height="wrap_content"
18         android:id="@+id/ll"
19         android:orientation="horizontal"
20         android:layout_gravity="center_horizontal"
21         >
22         
23     </LinearLayout>
24     <TextView 
25         android:layout_width="match_parent"
26         android:layout_height="match_parent"
27         android:layout_weight="1"
28         />
29 </LinearLayout>

3、MainActivity代码

  1 package com.zyhui.zyh_adv2;
  2 
  3 import java.io.IOException;
  4 import java.io.InputStream;
  5 import java.net.HttpURLConnection;
  6 import java.net.URL;
  7 import java.util.ArrayList;
  8 import java.util.List;
  9 
 10 import android.os.AsyncTask;
 11 import android.os.Bundle;
 12 import android.os.Handler;
 13 import android.support.v4.view.PagerAdapter;
 14 import android.support.v4.view.ViewPager;
 15 import android.support.v4.view.ViewPager.OnPageChangeListener;
 16 import android.util.Log;
 17 import android.view.View;
 18 import android.view.ViewGroup;
 19 import android.widget.ImageView;
 20 import android.widget.LinearLayout;
 21 import android.app.Activity;
 22 import android.graphics.Bitmap;
 23 import android.graphics.BitmapFactory;

//============================================
//1、要理解往ViewPager中加载广告图片
//2、广告图片切换时，下面的小圆圈跟着切换
//3、广告相隔一定的时间，自动切换
//
//注意初始化视图时所做的事情
//============================================

 24 
 25 public class MainActivity extends Activity implements OnPageChangeListener {
 26     private ViewPager vp;
 27     private LinearLayout ll;
 28     private List<ImageView> views;
 29     private List<Banner> banners;
 30     private int currentIndex = 300;
 31     private long lastTime;
 32     private MyAdapter adapter;
 33     private Handler handler = new Handler();
 34     private Runnable run = new Runnable(){
 35         @Override
 36         public void run() {
 37             if(System.currentTimeMillis() - lastTime > 1000){
 38                 currentIndex++;
 39                 vp.setCurrentItem(currentIndex);//实现自动切换的方法
 40                 //Log.i("zyh",currentIndex+"--aakk");
 41                 lastTime = System.currentTimeMillis();
 42             }
 43             
 44             handler.postDelayed(run, 1000);
 45         }
 46     };
 47     
 48     @Override
 49     protected void onCreate(Bundle savedInstanceState) {
 50         super.onCreate(savedInstanceState);
 51         setContentView(R.layout.activity_main);
 52         
 53         initView();
 54     }
 55     
 56     private void initView() {
 57         vp = (ViewPager) findViewById(R.id.vp);
 58         ll = (LinearLayout) findViewById(R.id.ll);
 59         views = new ArrayList<ImageView>();
 60         banners = new ArrayList<Banner>();
 61         for(int i=0; i<5; i++){
 62             ImageView img = new ImageView(this);
 63             img.setImageResource(android.R.color.white);
 64             views.add(img);//广告内容
 65             
 66             Banner banner = new Banner();
 67             banner.setUrl("http://192.168.1.100/android/adv/lmm"+(i+1)+".jpg");
 68             banners.add(banner);
 69             
 70             //广告图片下面的小圆
 71             ImageView img_circle = new ImageView(this);
 72             img_circle.setImageResource(R.drawable.nomal);
 73             img_circle.setPadding(10, 5, 10, 5);
 74             ll.addView(img_circle);
 75             
 76             //启动异步任务
 77             MyHttpBannerTask task = new MyHttpBannerTask();
 78             task.execute(banner.getUrl(),String.valueOf(i));
 79         }
 80         
 81         adapter = new MyAdapter();
 82         vp.setAdapter(adapter);
 83         vp.setCurrentItem(300);
 84         
 85         //通过这个的监听，来实现小圆圈切换
 86         vp.setOnPageChangeListener(this);
 87         
 88         lastTime = System.currentTimeMillis();
 89         handler.postDelayed(run, 2000);//实现自动切换方法
 90     }
 91     
 92     //PagerAdapter可以参考:http://www.tuicool.com/articles/NvuYJz
 93     //和http://blog.csdn.net/harvic880925/article/details/38487149
 94     private class MyAdapter extends PagerAdapter{
 95 
 96         //返回当前有效视图的个数
 97         @Override
 98         public int getCount() {
 99             // TODO Auto-generated method stub
100             return Integer.MAX_VALUE;
101         }
102         
103         /**
104          * 功能：该函数用来判断instantiateItem(ViewGroup, int)函数所返回来的Key与一个页面视图是否是代表的同一个视图
105          * (即它俩是否是对应的，对应的表示同一个View)
106          *    返回值：如果对应的是同一个View，返回True，否则返回False。
107          */
108         @Override
109         public boolean isViewFromObject(View view, Object object) {
110             // TODO Auto-generated method stub
111             return view == object;
112         }
113         
114         //这个函数的实现的功能是创建指定位置的页面视图
115         @Override
116         public Object instantiateItem(ViewGroup container, int position) {
117             int index = position%views.size();
118             ((ViewPager)container).addView(views.get(index));
119             //Log.i("zyh", position + "----bbbb");
120             return views.get(index);
121         }
122         
123         // PagerAdapter只缓存三张要显示的图片，如果滑动的图片超出了缓存的范围，就会调用这个方法，将图片销毁-已验证
124         @Override
125         public void destroyItem(ViewGroup container, int position, Object object) {
126             //Log.i("zyh", position+"--abc");
127             ((ViewPager)container).removeView(views.get(position%views.size()));
128         }
129     }
130 
131     @Override
132     public void onPageScrolled(int position, float positionOffset,
133             int positionOffsetPixels) {
134         // TODO Auto-generated method stub
135         
136     }
137 
138     @Override
139     public void onPageSelected(int position) {
140         currentIndex = position;
141         //Log.i("zyh",currentIndex+"--bbkk");//手主动滑动时,currentIndex才有可能变小
142         int index = position%views.size();
143         setCurrentSelector(index);
144         lastTime = System.currentTimeMillis();
145     }
146 
147     //小圆圈切换
148     private void setCurrentSelector(int index) {
149         for(int i=0; i<ll.getChildCount(); i++){
150             ImageView child = (ImageView) ll.getChildAt(i);
151             if(i == index){
152                 child.setImageResource(R.drawable.select);
153             }else{
154                 child.setImageResource(R.drawable.nomal);
155             }
156         }
157     }
158 
159     @Override
160     public void onPageScrollStateChanged(int state) {
161         // TODO Auto-generated method stub
162         
163     }
164     
165     @Override
166     protected void onDestroy() {
167         super.onDestroy();
168         handler.removeCallbacks(run);
169     }
170     
171     //异步任务
172     private class MyHttpBannerTask extends AsyncTask<String, Void, Bitmap>{
173         private int position;
174         @Override
175         protected Bitmap doInBackground(String... params) {
176             Bitmap bitmap = null;
177             String path = params[0];
178             int position = Integer.valueOf(params[1]);
179             try {
180                 bitmap = loadImageByUrl(path);
181             } catch (Exception e) {
182                 // TODO Auto-generated catch block
183                 e.printStackTrace();
184             }
185             
186             banners.get(position).setBitmap(bitmap);
187             this.position = position;
188             return bitmap;
189         }
190         
191         @Override
192         protected void onPostExecute(Bitmap result) {
193             super.onPostExecute(result);
194             if(result != null){
195                 views.get(position).setImageBitmap(result);
196             }
197         }
198     }
199 
200     public Bitmap loadImageByUrl(String path){
201         //Log.i("zyh", path);
202         Bitmap bitmap = null;
203         try {
204             URL url = new URL(path);
205             HttpURLConnection conn = (HttpURLConnection) url.openConnection();
206             conn.setRequestMethod("GET");
207             conn.setReadTimeout(5000);
208             int code = conn.getResponseCode();
209             //Log.i("zyh", code + "");
210             if(code == 200){
211                 InputStream is = conn.getInputStream();
212                 bitmap = BitmapFactory.decodeStream(is);
213             }
214         }catch (IOException e) {
215             e.printStackTrace();
216         }
217         return bitmap;
218     }
219 
220 }

4、辅助类

 1 package com.zyhui.zyh_adv2;
 2 
 3 import android.graphics.Bitmap;
 4 
 5 public class Banner {
 6     private String url;
 7     private Bitmap bitmap;
 8     
 9     public Banner() {
10     }
11     
12     public Banner(String url, Bitmap bitmap) {
13         this.url = url;
14         this.bitmap = bitmap;
15     }
16     
17     
18     public String getUrl() {
19         return url;
20     }
21     public void setUrl(String url) {
22         this.url = url;
23     }
24     public Bitmap getBitmap() {
25         return bitmap;
26     }
27     public void setBitmap(Bitmap bitmap) {
28         this.bitmap = bitmap;
29     }
30     
31 }

posted @ 2016-05-31 22:31 zhongyinghe 阅读(176) 评论(0) 收藏举报

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