毕加索图像重新加载滚动在列表视图

Question

我有一个问题，当我滚动我的列表视图，图像似乎继续重新加载自己，它使得列表视图滞后很多。 我能做些什么来防止这种情况发生，我之前在我的listview中做过这件事，而且它没有这样做。

public class PostsAdapter extends BaseAdapter{ 
    public List<PostList> postList; 
    protected Context context; 

    public void add(PostList object,int position) { 
      postList.add(position,object); 
     } 

     public PostsAdapter(Context context) { 
      this.context = context; 
      postList = new ArrayList<PostList>(); 
     } 

    @Override 
    public int getCount() { 
     // TODO Auto-generated method stub 
     return postList.size(); 
    } 

    @Override 
    public Object getItem(int position) { 
     // TODO Auto-generated method stub 
     return postList.get(position); 
    } 

    @Override 
    public long getItemId(int position) { 
     // TODO Auto-generated method stub 
     return position; 
    } 
    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     // TODO Auto-generated method stub 
     ViewHolder holder; 
     if(convertView == null){ 
      convertView = LayoutInflater.from(context).inflate(R.layout.posts_list, null); 
      holder = new ViewHolder(); 
      holder.image = (ImageView)convertView.findViewById(R.id.postImage); 
      holder.username = (TextView)convertView.findViewById(R.id.postUsername); 
      convertView.setTag(holder); 
     }else{ 
      holder = (ViewHolder)convertView.getTag(); 
     } 
     holder.username.setText(postList.get(position).user); 
     Picasso.with(context).load(postList.get(position).postPicture).into(holder.image); 

     return convertView; 
    } 
static class ViewHolder{ 
     ImageView image; 
     TextView username; 
    } 

Answer 1

public class PostsAdapter extends BaseAdapter 
    { 
     public List<PostList> postList; 
     protected Context context; 

    public PostsAdapter(Context context,ArrayList<PostList> List) 
    { 
     this.context = context; 
     postList = List; 
    } 

    @Override 
    public int getCount() 
    { 
    // TODO Auto-generated method stub 
    return postList.size(); 
    } 

@Override 
public Object getItem(int position) { 
    // TODO Auto-generated method stub 
    return postList.get(position); 
} 

@Override 
public long getItemId(int position) { 
    // TODO Auto-generated method stub 
    return position; 
} 
@Override 
public View getView(int position, View convertView, ViewGroup parent) { 
    // TODO Auto-generated method stub 
    ViewHolder holder; 
    if(convertView == null){ 
     convertView = LayoutInflater.from(context).inflate(R.layout.posts_list, null); 
     holder = new ViewHolder(); 
     holder.image = (ImageView)convertView.findViewById(R.id.postImage); 
     holder.username = (TextView)convertView.findViewById(R.id.postUsername); 
     convertView.setTag(holder); 
    }else{ 
     holder = (ViewHolder)convertView.getTag(); 
    } 
    holder.username.setText(postList.get(position).user); 
    Picasso.with(context).load(postList.get(position).postPicture).into(holder.image); 

    return convertView; 
} 
    static class ViewHolder 
{ 
    ImageView image; 
    TextView username; 
} 

Answer 2

当用户触发一扔MotionEvent，应用程序下载图像，它需要停止滚动的浓缩，然后回到尽快停止运动再次下载图像。这样做的效果几乎是神奇的。

此外，谷歌给出了代码，以显示它是如何完成的。你可以在这里找到它 - https://github.com/google/iosched

下面是如何添加一个滚动监听器来停止和启动队列的快速片段。

listView.setOnScrollListener(new OnScrollListener() { 
    @Override 
    public void onScrollStateChanged(AbsListView listView, int scrollState) { 
     // Pause disk cache access to ensure smoother scrolling 
     if (scrollState == AbsListView.OnScrollListener.SCROLL_STATE_FLING) { 
      imageLoader.stopProcessingQueue(); 
     } else { 
      imageLoader.startProcessingQueue(); 
     } 
    } 

    @Override 
    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { 
      // TODO Auto-generated method stub 
    } 
}); 

Answer 3

我也有类似的问题，并结合从Detecting the scrolling direction in the adapter (up/down)和Fetch images with Callback in Picasso?提示。也就是说，我通过将适配器访问的最后位置与当前位置进行比较来检测用户是向上还是向下滚动，并将他们遇到的下一个图像加载到空目标中以加热缓存。

Answer 4

使用调整与毕加索

    Picasso.with(context) 
       .load(imageURL) 
       .tag(context) 
       .placeholder(R.drawable.kanye8080s) 
       .error(R.drawable.stadiumarcadium) 
       .into(imageView) 
       .resize(x,y); 

//这绝对有帮助