android - Listview 上的通用图像加载器很慢

Question

我已经确保我只有一个 ImageLoader 实例，所以我知道这不是问题，出于某种原因，它仅在显示从网络加载的全新图像时才会滞后。所以我假设它与 UI 断断续续的事实有关，因为它正在解码图像，但我认为 Universal Image Loader 异步处理所有内容。这是我的 BaseAdapter 的 getView 方法。

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    LayoutInflater inflater = (LayoutInflater) mContext
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    JSONObject thePost = null;
    try { 
        thePost = mPosts.getJSONObject(position).getJSONObject("data");
    } catch (Exception e) {
        System.out.println("errreoroer");
    }

    LinearLayout postItem = (LinearLayout) inflater.inflate(R.layout.column_post, parent, false);   

    String postThumbnailUrl = null;


    try {

        //parse thumbnail
        postThumbnailUrl = thePost.getString("thumbnail");          

    } catch (Exception e) {}        

    //grab the post view objects

    ImageView postThumbnailView = (ImageView)postItem.findViewById(R.id.thumbnail);

    if (!(postThumbnailUrl.equals("self") || postThumbnailUrl.equals("default") || postThumbnailUrl.equals("nsfw")))
        mImageLoader.displayImage(postThumbnailUrl, postThumbnailView);         


    return postItem;

}

Answer 1

我认为您的问题不是 ImageLoader。事实上，您没有使用系统传回给您的 convertView，因此您根本没有回收 View ，您只是为列表的每一行增加一个新 View 。

尝试更改您的 getView() 方法以使用 convertView:

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    LinearLayout postItem = convertView
    if(null == postItem){
        LayoutInflater inflater = (LayoutInflater) mContext
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        postItem = (LinearLayout) inflater.inflate(R.layout.column_post, parent, false);   
    }

    JSONObject thePost = null;
    try { 
        thePost = mPosts.getJSONObject(position).getJSONObject("data");
    } catch (Exception e) {
        System.out.println("errreoroer");
    }
    String postThumbnailUrl = null;
    try {

        //parse thumbnail
        postThumbnailUrl = thePost.getString("thumbnail");          

    } catch (Exception e) {}        

    //grab the post view objects
    ImageView postThumbnailView = (ImageView)postItem.findViewById(R.id.thumbnail);
    if (!(postThumbnailUrl.equals("self") || postThumbnailUrl.equals("default") || postThumbnailUrl.equals("nsfw")))
        mImageLoader.displayImage(postThumbnailUrl, postThumbnailView);         

    return postItem;

}