Question

我正在尝试通过AsyncTask将数据设置为适配器。这引起了很多悲痛 - 最近一次尝试设置阵列适配器时。

以下方法称为onPostExecute（）;

private void setQueues(final JSONObject[] qInfo) 
{
    queues = new QueueItem[qInfo.length];

    for(int i = 0; i < qInfo.length; i++)
    {
        queues[i] = new QueueItem();
        //final int ii = i;

        // Formatting the queue title
        String name = qInfo[i].optString("name").replace("-", " ");
        queues[i].label = name;

        try {
            if(qInfo[i].getString("active").contains("1"))
            {
                queues[i].value = true;
            }
            else
            {
                queues[i].value = false;
            }
        } 
        catch (JSONException e) 
        {
            e.printStackTrace();
        }
    }
    lv.setAdapter(new QueueAdapter(getActivity(), 
            R.layout.queues_items, queues));

这会导致以下异常运行时：link here

编辑：根据要求，这是QueueAdapter：

public class QueueAdapter extends ArrayAdapter<QueueItem>{

Context context; 
int layoutResourceId;    
QueueItem data[] = null;

public QueueAdapter(Context context, int layoutResourceId, QueueItem[] data) {
    super(context, layoutResourceId, data);
    this.layoutResourceId = layoutResourceId;
    this.context = context;
    this.data = data;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row = convertView;
    QueueHolder holder = null;

    if(row == null)
    {
        LayoutInflater inflater = ((Activity)context).getLayoutInflater();
        row = inflater.inflate(layoutResourceId, parent, false);

        holder = new QueueHolder();
        holder.queueswitch = (Switch)row.findViewById(R.id.queues_item_switch);
        holder.txtLabel = (TextView)row.findViewById(R.id.queues_item_text);

        row.setTag(holder);
    }
    else
    {
    holder = (QueueHolder)row.getTag();
    }

    QueueItem queue = data[position];
    holder.txtLabel.setText(queue.label);
    holder.queueswitch.setChecked(queue.value);

    return row;
}

static class QueueHolder
{
    Switch queueswitch;
    TextView txtLabel;
}
}

Answer 1

lv.setAdapter(new QueueAdapter(getActivity(), 
            R.layout.queues_items, queues));

此代码段应该在try块中..因为如果有JSONException该数组中的所有元素都将为null ...

我的意思是说..把for循环放在try块而不是oppt ..如果你仍然想在发生Exception时循环..那么尝试使用Collections而不是array ..

NullPointer为ListView设置适配器时出现异常

1 个答案: