Android应用List图标异步加载
1、创建异步加载类:
Java代码
import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.os.Message;
import android.widget.ImageView;
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;
public class AsyncImageLoader {
// SoftReference是软引用,是为了更好的为了系统回收变量
private HashMap<String, SoftReference<Drawable>> imageCache;
public AsyncImageLoader() {
imageCache = new HashMap<String, SoftReference<Drawable>>();
}
public Drawable loadDrawable(final String imageUrl, final ImageView imageView,
final ImageCallback imageCallback) {
if (imageCache.containsKey(imageUrl)) {
// 从缓存中获取
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, imageView, imageUrl);
}
};
// 建立新一个新的线程下载图片
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;
}
// 回调接口
public inte易做图ce ImageCallback {
public void imageLoaded(Drawable imageDrawable, ImageView imageView, String imageUrl);
}
}
import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.os.Message;
import android.widget.ImageView;
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;
public class AsyncImageLoader {
// SoftReference是软引用,是为了更好的为了系统回收变量
private HashMap<String, SoftReference<Drawable>> imageCache;
public AsyncImageLoader() {
imageCache = new HashMap<String, SoftReference<Drawable>>();
}
public Drawable loadDrawable(final String imageUrl, final ImageView imageView,
final ImageCallback imageCallback) {
if (imageCache.containsKey(imageUrl)) {
// 从缓存中获取
SoftReference<Drawable> softReference = imageCache.get(imageUrl);
Drawable drawable = softReference.get();
if (drawable != null) {
return drawable;
}
}
final Handler handler = new Handler() {
public
补充:移动开发 , Android ,