毕加索将图片加载到列表适配器中的错误图像视图中

Question

我正在使用picasso将服务器中的图像加载到列表视图项,如下所示:

public View getView(int position, View convertView, ViewGroup parent) {
    LayoutInflater inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View participantView;
    if(convertView == null) {
        participantView = inflater.inflate(R.layout.participant_item, parent, false);
    } else {
        participantView = convertView;
    }

    TextView textView = (TextView) participantView.findViewById(R.id.participantName);
    textView.setText(getItem(position).getName());
    ImageView imageView = (ImageView) participantView.findViewById(R.id.participantImage);
    String profilePic = getItem(position).getProfilePic();

    if(!profilePic.equals("None")) {
        Log.d("tom.debug", "creating picture for user: " + getItem(position).getName());
        Picasso.with(this.context)
            .load(urlToProfilePics + profilePic)
            .placeholder(R.drawable.sample_0)
            .resize(52, 52)
            .into(imageView);
    } else {
        //load the place holder into the image view
        Picasso.with(this.context).load(R.drawable.sample_0);
    }

    if(!getItem(position).isHere()) {
        imageView.setColorFilter(Color.DKGRAY, PorterDuff.Mode.MULTIPLY);
    }

    return participantView;
}

if语句下的调试日志仅针对真正具有配置文件图片的用户触发.(没有的用户将获得值None).

但是,一些其他列表视图项(没有配置文件pic)也会加载图片.

另一个有用的事实(我认为):当在列表中上下滚动时,获取错误的项目会发生变化.

我不确定我在这里缺少什么.

Answer 1

确保在每次要从适配器上的getView()上使用Picasso时调用cancelRequest.

// 1st: reset the imageView
Picasso.with(this.context).cancelRequest(holder.imageView); 

// 2nd start a new load for the imageView
Picasso.with(this.context).load(...).into(holder.imageView); 

原因是您从convertView参数重用的视图属于Picasso可能已经为另一张图片加载的上一行.

这只是在使用convertView时才真正需要,如果你刚刚为新布局充气,则不需要它.但是你总是可以调用以使代码更容易.

Answer 2

我想我也遇到过同样的情况。我建议您的适配器使用ViewHolder模式。

会是这样的。

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

    final ViewHolder holder;
    View participantView = convertView;
    if (participantView == null || participantView.getTag() == null) {
        LayoutInflater inflater = (LayoutInflater) mContext
        .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            // don't forget to inflate the same layout
        participantView = inflater.inflate(R.layout.participant_item, null);
        holder = getHolder(participantView);
        assert participantView != null;
        participantView.setTag(holder);
    } else {
        holder = (ViewHolder) participantView.getTag();
    }

    holder.textView.setText(getItem(position).getName());
    String profilePic = getItem(position).getProfilePic();

    if(!profilePic.equals("None")) {
        Log.d("tom.debug", "creating picture for user: " + getItem(position).getName());
        Picasso.with(this.context)
        .load(urlToProfilePics + profilePic)
        .placeholder(R.drawable.sample_0)
        .resize(52, 52)
        .into(holder.imageView);
    } else {
        //load the place holder into the image view
        Picasso.with(this.context).load(R.drawable.sample_0);
    }

    if(!getItem(position).isHere()) {
        holder.imageView.setColorFilter(Color.DKGRAY, PorterDuff.Mode.MULTIPLY);
    }

    resetViews(participantView);

    return participantView;
}

void resetViews(View v) {
    ViewHolder mHolder = new ViewHolder(v);
    mHolder.textView.invalidate();
    mHolder.imageView.invalidate();
}

static class ViewHolder { 
  TextView textView;
  ImageView imageView;
}