Picasso IllegalArgumentException

Question

我正在尝试使用Picasso加载Facebook照片以获取列表视图。

我收到“ java.lang.IllegalArgumentException：Target不能为null ”

在这一行：

.into(holder.userpicture);

如果用户图片ImageView是'目标'，那么我不明白。我的猜测是它与我的适配器有关，但我无法弄清楚是什么。

非常感谢所有人的帮助！

修改

我发现了问题。我犯了一个粗心的错误。在这一行，我忘记了convertView部分：

holder.userpicture=(ImageView)findViewById(R.id.userpicture);

logcat的：

06-01 16:37:14.392: E/AndroidRuntime(7885): java.lang.IllegalArgumentException: Target must not be null.
06-01 16:37:14.392: E/AndroidRuntime(7885):     at com.squareup.picasso.RequestCreator.into(RequestCreator.java:479)
06-01 16:37:14.392: E/AndroidRuntime(7885):     at com.squareup.picasso.RequestCreator.into(RequestCreator.java:462)
06-01 16:37:14.392: E/AndroidRuntime(7885):     at com.example.mywebsite.AllProductsActivity$MyAdapter.getView(AllProductsActivity.java:327)

MyAdapter：

public class MyAdapter extends ArrayAdapter<HashMap<String, String>> {

    Context context;
    int resourceId;
    LayoutInflater inflater;
    private Context mContext;


    ArrayList<HashMap<String, String>>  items;
    public MyAdapter (Context context, int resourceId, ArrayList<HashMap<String, String>> items)
    {
        super(context, resourceId, items);
        mContext = context;
        this.items =items;
        inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent){
        final ViewHolder holder;
        if (convertView == null){

            convertView = inflater.inflate(R.layout.list_item, null);

            holder = new ViewHolder();
            holder.name = (TextView)convertView.findViewById(R.id.name);
            holder.userpicture=(ImageView)findViewById(R.id.userpicture);
            convertView.setTag(holder);

        } else {

            holder = (ViewHolder)convertView.getTag();
        }

        HashMap<String,String> item = (HashMap<String,String> ) items.get(position);
        if (item != null)
        {

            String facebookProfilePicUrl = "http://graph.facebook.com/"+TAG_FACEBOOKID+"/picture?width=100&height=100";

           Picasso.with(mContext).load(facebookProfilePicUrl)
.into(holder.userpicture);

            holder.name.setText(item.get(TAG_FACEBOOKID));


        }

        return convertView;
    }

    public class ViewHolder
    {
        TextView    name;
        ImageView userpicture;
    }
}

Answer 1

据推测，holder.userpicture是null。 res/layout/list_item没有名为userpicture的窗口小部件，或者您需要清理项目（例如，项目＆gt;从Eclipse主菜单中清除）。

另外，please use the three-parameter version of inflate()，如果您将行布局更改为使用RelativeLayout根，则不会遇到问题。

Answer 2

它为我工作::）

第1步：

在顶部声明您的图片视图：

public class BaseAdapterShow extends BaseAdapter {
    ImageView imgView;
}

第2步：

在你的getView（）中参考图像

实施例

imgView = (ImageView) convertView.findViewById(R.id.catrImg);

步骤3：

直接使用Picasa，如下所示：

Picasso.with(context).load(imageurl)
    .placeholder(R.drawable.profilepic)
    .error(R.drawable.profilepic)
    .resize(250, 200).into(imgView);

Answer 3

它会很好用★★★

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

    if (convertView == null){

        convertView = inflater.inflate(R.layout.list_item, null);

        ViewHolder holder = new ViewHolder();
        holder.name = (TextView)convertView.findViewById(R.id.name);
        holder.userpicture=(ImageView)findViewById(R.id.userpicture);
        convertView.setTag(holder);

    } else {

        holder = (ViewHolder)convertView.getTag();
    }

    ViewHolder holder = (ViewHolder) convertView.getTag();

    HashMap<String,String> item = (HashMap<String,String> ) items.get(position);
    if (item != null)
    {

        String facebookProfilePicUrl = "http://graph.facebook.com/"+TAG_FACEBOOKID+"/picture?width=100&height=100";

       Picasso.with(mContext).load(facebookProfilePicUrl).into(holder.userpicture);

        holder.name.setText(item.get(TAG_FACEBOOKID));


    }

    return convertView;
}

public class ViewHolder
{
    TextView    name;
    ImageView userpicture;
}

}