畢加索圖像重新加載滾動在列表視圖

Question

我有一個問題，當我滾動我的列表視圖，圖像似乎繼續重新加載自己，它使得列表視圖滯後很多。 我能做些什麼來防止這種情況發生，我之前在我的listview中做過這件事，而且它沒有這樣做。

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

當用戶觸發一扔MotionEvent，應用程序下載圖像，它需要停止滾動的濃縮，然後回到儘快停止運動再次下載圖像。這樣做的效果幾乎是神奇的。

此外，谷歌給出了代碼，以顯示它是如何完成的。你可以在這裏找到它 - https://github.com/google/iosched

下面是如何添加一個滾動監聽器來停止和啓動隊列的快速片段。

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

我也有類似的問題，並結合從Detecting the scrolling direction in the adapter (up/down)和Fetch images with Callback in Picasso?提示。也就是說，我通過將適配器訪問的最後位置與當前位置進行比較來檢測用戶是向上還是向下滾動，並將他們遇到的下一個圖像加載到空目標中以加熱緩存。

Answer 4

使用調整與畢加索

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

//這絕對有幫助