ListView设置快速滑动时不加载图片

 1 package com.example.listview_01;
 2 
 3 import android.widget.AbsListView;
 4 import android.widget.BaseAdapter;
 5 import android.widget.AbsListView.OnScrollListener;
 6 
 7 public class ListViewOnscrollLister implements OnScrollListener {
 8 
 9     // 添加标志位
10     public static boolean isLoadImg = true;
11 
12     public BaseAdapter basedapter;
13 
14     public ListViewOnscrollLister(BaseAdapter basedapter) {
15         this.basedapter = basedapter;
16     }
17 
18     @Override
19     public void onScrollStateChanged(AbsListView view, int scrollState) {
20         switch (scrollState) {
21         case OnScrollListener.SCROLL_STATE_FLING:
22             isLoadImg = false;
23             break;
24         case OnScrollListener.SCROLL_STATE_IDLE:
25             isLoadImg = true;
26             basedapter.notifyDataSetChanged();
27             break;
28         case OnScrollListener.SCROLL_STATE_TOUCH_SCROLL:
29             isLoadImg = false;
30             break;
31 
32         }
33 
34     }
35 
36     @Override
37     public void onScroll(AbsListView view, int firstVisibleItem,
38             int visibleItemCount, int totalItemCount) {
39         // TODO Auto-generated method stub
40 
41     }
42 
43 }

 1 package com.example.listview_01;
 2 
 3 import java.util.List;
 4 import java.util.concurrent.ArrayBlockingQueue;
 5 import java.util.concurrent.BlockingQueue;
 6 import java.util.concurrent.ThreadPoolExecutor;
 7 import java.util.concurrent.TimeUnit;
 8 
 9 import android.content.Context;
10 import android.os.Handler;
11 import android.util.Log;
12 import android.view.LayoutInflater;
13 import android.view.View;
14 import android.view.ViewGroup;
15 import android.widget.BaseAdapter;
16 import android.widget.ImageView;
17 import android.widget.TextView;
18 
19 import com.example.listview_01.ImageLoader.ImgResult;
20 
21 public class ImgAdapter extends BaseAdapter {
22 
23     private Context context;
24     private List<ViewItem> list;
25     private LayoutInflater inflater;
26     private BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<Runnable>(
27             200);
28     // 设置线程线程池
29     private ThreadPoolExecutor executor = new ThreadPoolExecutor(4, 10, 200,
30             TimeUnit.SECONDS, workQueue);
31     private Handler handler = new Handler() {
32         public void handleMessage(android.os.Message msg) {
33             ImgResult imgresult = (ImgResult) msg.obj;
34             imgresult.img.setImageBitmap(imgresult.bitmap);
35         };
36     };
37 
38     public ImgAdapter(Context context, List<ViewItem> list) {
39         this.context = context;
40         this.list = list;
41         inflater = LayoutInflater.from(context);
42     }
43 
44     @Override
45     public int getCount() {
46         return list.size();
47     }
48 
49     @Override
50     public Object getItem(int position) {
51         return list.get(position);
52     }
53 
54     @Override
55     public long getItemId(int position) {
56         return position;
57     }
58 
59     @Override
60     public View getView(int position, View convertView, ViewGroup parent) {
61         // TODO Auto-generated method stub
62         ImgHolder imgHolder = null;
63         if (null == convertView) {
64             convertView = inflater.inflate(R.layout.activity_img, null);
65             imgHolder = new ImgHolder(convertView);
66             convertView.setTag(imgHolder);
67         } else {
68             imgHolder = (ImgHolder) convertView.getTag();
69         }
70         ViewItem item = list.get(position);
71         imgHolder.addressTxt.setText(item.getAddress());
72         imgHolder.titleTxt.setText(item.getTitle());
73         // 设置快速滚动不加载图片停止滚动时加载图片
74         if (MainActivity.onscroll.isLoadImg) {
75             executor.submit(new ImageLoader(item.getImgUrl(), handler,
76                     imgHolder.imgView));
77         }
78         return convertView;
79     }
80 
81     class ImgHolder {
82         public TextView titleTxt;
83         public TextView addressTxt;
84         public ImageView imgView;
85 
86         public ImgHolder(View convertView) {
87             titleTxt = (TextView) convertView.findViewById(R.id.title);
88             addressTxt = (TextView) convertView.findViewById(R.id.content);
89             imgView = (ImageView) convertView.findViewById(R.id.imageView1);
90         }
91     }
92 }

 1 package com.example.listview_01;
 2 
 3 import java.io.IOException;
 4 import java.io.InputStream;
 5 import java.net.HttpURLConnection;
 6 import java.net.MalformedURLException;
 7 import java.net.URL;
 8 
 9 import android.graphics.Bitmap;
10 import android.graphics.BitmapFactory;
11 import android.os.Handler;
12 import android.os.Message;
13 import android.widget.ImageView;
14 
15 public class ImageLoader implements Runnable {
16 
17     private String path;
18     private Handler handler;
19     private ImageView imgView;
20 
21     public ImageLoader(String url, Handler handler, ImageView imgView) {
22         this.path = url;
23         this.handler = handler;
24         this.imgView = imgView;
25     }
26 
27     @Override
28     public void run() {
29         try {
30             URL url = new URL(path);
31             HttpURLConnection connection = (HttpURLConnection) url
32                     .openConnection();
33             connection.setDoInput(true);
34             connection.setRequestMethod("GET");
35             InputStream is = connection.getInputStream();
36             Bitmap bitmap = BitmapFactory.decodeStream(is);
37             Message msg = Message.obtain();
38             msg.obj = new ImgResult(imgView, bitmap);
39             handler.sendMessage(msg);
40             is.close();
41             connection.disconnect();
42         } catch (IOException e) {
43             // TODO Auto-generated catch block
44             e.printStackTrace();
45         }
46     }
47 
48     public class ImgResult {
49         public ImageView img;
50         public Bitmap bitmap;
51 
52         public ImgResult(ImageView imgs, Bitmap bitmaps) {
53             img = imgs;
54             bitmap = bitmaps;
55         }
56     }
57 }

1 adapter = new ImgAdapter(this, list);
2 listView.setAdapter(adapter);
3 onscroll = new ListViewOnscrollLister(adapter);
4 listView.setOnScrollListener(onscroll);