我在ListActivity中有一个扩展的BaseAdapter:

private static class RequestAdapter extends BaseAdapter {

其中定义了一些处理程序和runnable
// Need handler for callbacks to the UI thread
    final Handler mHandler = new Handler();

    // Create runnable for posting
    final Runnable mUpdateResults = new Runnable() {
        public void run() {
            loadAvatar();
        }
    };

    protected static void loadAvatar() {
        // TODO Auto-generated method stub
        //ava.setImageBitmap(getImageBitmap("URL"+pic));
        buddyIcon.setImageBitmap(avatar);
    }

在适配器的getview函数中,我得到如下视图:
if (convertView == null) {
            convertView = mInflater.inflate(R.layout.messageitem, null);

            // Creates a ViewHolder and store references to the two children views
            // we want to bind data to.
            holder = new ViewHolder();
            holder.username = (TextView) convertView.findViewById(R.id.username);
            holder.date = (TextView) convertView.findViewById(R.id.dateValue);
            holder.time = (TextView) convertView.findViewById(R.id.timeValue);
            holder.notType = (TextView) convertView.findViewById(R.id.notType);
            holder.newMsg = (ImageView) convertView.findViewById(R.id.newMsg);
            holder.realUsername = (TextView) convertView.findViewById(R.id.realUsername);
            holder.replied = (ImageView) convertView.findViewById(R.id.replied);
            holder.msgID = (TextView) convertView.findViewById(R.id.msgID_fr);
            holder.avatar = (ImageView) convertView.findViewById(R.id.buddyIcon);
            holder.msgPreview = (TextView) convertView.findViewById(R.id.msgPreview);


            convertView.setTag(holder);
        } else {
            // Get the ViewHolder back to get fast access to the TextView
            // and the ImageView.
            holder = (ViewHolder) convertView.getTag();
        }

图像是这样加载的:
Thread sepThread = new Thread() {
                    public void run() {
                        String ava;
                        ava = request[8].replace(".", "_micro.");
                        Log.e("ava thread",ava+", username: "+request[0]);
                        avatar = getImageBitmap(URL+ava);
                        buddyIcon = holder.avatar;
                        mHandler.post(mUpdateResults);
                        //holder.avatar.setImageBitmap(getImageBitmap(URL+ava));
                    }
                };
                sepThread.start();

现在,我遇到的问题是,如果有更多的项目需要显示同一张图片,并不是所有这些图片都会显示出来。当你在列表中上下滚动时,也许你最终会填满所有的列表。
当我尝试注释行(holder.avatar.setimagebitmap…)时,应用程序有时会强制关闭“只有创建视图的线程可以请求…”。但只是有时候。
你知道我该怎么解决吗?任何一种选择。

最佳答案

当调用getview时,您得到了一个avatar imageview。您应该将此实例传递给septhread,septhread应该将此实例传递给mupdateresults。这样,位图将精确显示到下载它的imageview。否则位图将显示给某些不正确的BudddyIcon实例。您的线程下载了一段时间的图像,当它准备好时,BuddyIcon引用了另一个ImageView,因为已经调用了另一个GetView。
应该是这样的:

public View getView(...){
  //skip
  (new SepThread(holder.avatar)).start();
}

public class SepThread extends Thread() {
    ImageView imageView;
    public SepThread(ImageVIew iv){
      imageView=iv;
    }
    public void run() {
        //skip
        Bitmap avatar = getImageBitmap(URL+ava);
        mHandler.post(new UpdateResults(imageView, avatar));
    }
};

class UpdateResults extends Runnable() {
  ImageView imageView;
  Bitmap bitmap;
  public UpdateResults(ImageView iv, Bitmap b){
    imageView=iv;
    bitmap=b;
  }
  public void run() {
      loadAvatar(imageView, bitmap);
  }
};

protected static void loadAvatar(ImageView iv, Bitmap b) {
    iv.setImageBitmap(b);
}

当然,正如disretrospect上面所说的,你应该意识到回收的转换视图。
我做了一个完整的懒散的例子并发布了源码,可能也有帮助Lazy load of images in ListView

08-16 22:01