package cn.wangmeng.test;

import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.SoftReference;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;

import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.os.Message;

public class AsyncImageLoader {

private HashMap<String, SoftReference<Drawable>> imageCache;

public AsyncImageLoader() {
imageCache = new HashMap<String, SoftReference<Drawable>>();
}

public Drawable loadDrawable(final String imageUrl, final ImageCallback imageCallback) {
if (imageCache.containsKey(imageUrl)) {
SoftReference<Drawable> softReference = imageCache.get(imageUrl);
Drawable drawable = softReference.get();
if (drawable != null) {
return drawable;
}
}
final Handler handler = new Handler() {
public void handleMessage(Message message) {
imageCallback.imageLoaded((Drawable) message.obj, imageUrl);
}
};
new Thread() {
@Override
public void run() {
Drawable drawable = loadImageFromUrl(imageUrl);
imageCache.put(imageUrl, new SoftReference<Drawable>(drawable));
Message message = handler.obtainMessage(0, drawable);
handler.sendMessage(message);
}
}.start();
return null;
}

public static Drawable loadImageFromUrl(String url) {
URL m;
InputStream i = null;
try {
m = new URL(url);
i = (InputStream) m.getContent();
} catch (MalformedURLException e1) {
e1.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
Drawable d = Drawable.createFromStream(i, "src");
return d;
}

public interface ImageCallback {
public void imageLoaded(Drawable imageDrawable, String imageUrl);
}

}


package cn.wangmeng.test;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.widget.ListView;

public class AsyncListImage extends Activity {
private ListView list;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
list=(ListView)findViewById(R.id.list);
List<ImageAndText> dataArray=new ArrayList<ImageAndText>();
ImageAndText test=new ImageAndText("http://www.wangmeng.cn/images/logo.gif", "test");
ImageAndText test1=new ImageAndText("http://www.wangmeng.cn/images/ad/t1.gif", "test1");
ImageAndText test2=new ImageAndText("http://www.wangmeng.cn/images/ad/t3.gif", "test2");
dataArray.add(test);
dataArray.add(test1);
dataArray.add(test2);
ImageAndTextListAdapter adapter=new ImageAndTextListAdapter(this, dataArray, list);
list.setAdapter(adapter);

}
}


package cn.wangmeng.test;

public class ImageAndText {
private String imageUrl;
private String text;

public ImageAndText(String imageUrl, String text) {
this.imageUrl = imageUrl;
this.text = text;
}
public String getImageUrl() {
return imageUrl;
}
public String getText() {
return text;
}
}


package cn.wangmeng.test;

import java.util.List;

import cn.wangmeng.test.AsyncImageLoader.ImageCallback;

import android.app.Activity;
import android.graphics.drawable.Drawable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

public class ImageAndTextListAdapter extends ArrayAdapter<ImageAndText> {

private ListView listView;
private AsyncImageLoader asyncImageLoader;

public ImageAndTextListAdapter(Activity activity, List<ImageAndText> imageAndTexts, ListView listView) {
super(activity, 0, imageAndTexts);
this.listView = listView;
asyncImageLoader = new AsyncImageLoader();
}

public View getView(int position, View convertView, ViewGroup parent) {
Activity activity = (Activity) getContext();

// Inflate the views from XML
View rowView = convertView;
ViewCache viewCache;
if (rowView == null) {
LayoutInflater inflater = activity.getLayoutInflater();
rowView = inflater.inflate(R.layout.image_and_text_row, null);
viewCache = new ViewCache(rowView);
rowView.setTag(viewCache);
} else {
viewCache = (ViewCache) rowView.getTag();
}
ImageAndText imageAndText = getItem(position);

// Load the image and set it on the ImageView
String imageUrl = imageAndText.getImageUrl();
ImageView imageView = viewCache.getImageView();
imageView.setTag(imageUrl);
Drawable cachedImage = asyncImageLoader.loadDrawable(imageUrl, new ImageCallback() {
public void imageLoaded(Drawable imageDrawable, String imageUrl) {
ImageView imageViewByTag = (ImageView) listView.findViewWithTag(imageUrl);
if (imageViewByTag != null) {
imageViewByTag.setImageDrawable(imageDrawable);
}
}
});
if (cachedImage == null) {
imageView.setImageResource(R.drawable.default_image);
}else{
imageView.setImageDrawable(cachedImage);
}
// Set the text on the TextView
TextView textView = viewCache.getTextView();
textView.setText(imageAndText.getText());

return rowView;
}

}


package cn.wangmeng.test;

import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

public class ViewCache {

private View baseView;
private TextView textView;
private ImageView imageView;

public ViewCache(View baseView) {
this.baseView = baseView;
}

public TextView getTextView() {
if (textView == null) {
textView = (TextView) baseView.findViewById(R.id.text);
}
return textView;
}

public ImageView getImageView() {
if (imageView == null) {
imageView = (ImageView) baseView.findViewById(R.id.image);
}
return imageView;
}

}