android - Android Picasso 懒加载

Question

我在我的 android 项目中使用 Picasso 库。我的主要活动中有一个 ListView。所有行项都填充有来自使用 SAXParser 解析的 XML 的数据。我创建了处理列表项的自定义列表适配器。如何使用毕加索实现某种延迟加载图像。这是我的代码（自定义适配器）：

public class PicassoAdapter extends BaseAdapter {

    private Activity activity;
    private ArrayList<HashMap<String, String>> data;
    private static LayoutInflater inflater=null;

    public PicassoAdapter(Activity a, ArrayList<HashMap<String, String>> d)
    {
        activity = a;
        data=d;
        inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public int getCount() {
         return data.size();
    }


    @Override
    public Object getItem(int position) {
        return position;
    }

    @Override
    public long getItemId(int position) {
         return position;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        View vi=convertView;
        if(convertView==null)
            vi = inflater.inflate(R.layout.list_item, null);

        TextView title = (TextView) vi.findViewById(R.id.pid); // title
        ImageView image = (ImageView) vi.findViewById(R.id.slika1);//  slika

        HashMap<String, String> song = new HashMap<String, String>();
        song = data.get(position);

        Log.i("&&&&&&&&&&&&&&&",data.get(0).get(MainActivity.KEY_TITLE));

        // Setting all values in listview
        title.setText(song.get(MainActivity.KEY_TITLE));
        Picasso.with(vi.getContext()).load(song.get(MainActivity.KEY_THUMB_URL)).into(image);  
        return vi;
    }
}

Answer 1

对于ListView它的要求占位符

Picasso.with(vi.getContext())
    .load(song.get(MainActivity.KEY_THUMB_URL))
    .placeholder(R.drawable.user_placeholder)
    .error(R.drawable.user_placeholder_error)
    .into(image);