如何从ListView中提取对象 - getItemAtPosition不起作用

Question

我为我的实现了一个自定义适配器ListView.如何从特定列表项中提取对象.以下是我的自定义适配器的外观:

MyCustomAdapter.java

public class MyCustomAdapter extends ArrayAdapter<DashboardBean> {


Context context;
int layoutResourceId;
DashboardBean currentMRB;
Vector<DashboardBean> data;

public MyCustomAdapter(Context context, int layoutResourceId, Vector<DashboardBean> 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;
    MyStringReaderHolder holder;

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

        holder= new MyStringReaderHolder();

        holder.project = (TextView)row.findViewById(R.id.project);
        holder.workRequest = (TextView)row.findViewById(R.id.work_request);
        holder.startDate  = (TextView)row.findViewById(R.id.start_date);
        holder.status = (TextView) row.findViewById(R.id.status);

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

    DashboardBean mrb =data.elementAt(position);
    System.out.println("Position="+position);

     holder.project.setText(mrb.project);
    holder.workRequest.setText(mrb.workRequest);
    holder.startDate.setText(mrb.startDate);
    holder.status.setText(mrb.status);
    return row;
}





static class MyStringReaderHolder {
     TextView project, workRequest, startDate, status;

   }
}

这是DashboardBean.java

 public class DashboardBean {

    public String project;
    public String workRequest;
    public String startDate;
    public String status;   

    public DashboardBean(String project,String workRequest,String startDate,String status)
    {
        this.project = project;
        this.workRequest = workRequest;
        this.startDate = startDate;
        this.status = status;
    }
}

这是我调用onClickListener()的java片段:

mListView.setOnItemClickListener(new OnItemClickListener() {
      public void onItemClick(AdapterView<?> myAdapter, View myView, 
            int myItemInt, long mylng) {
        TableRow tableRow = (TableRow) (mListView.getItemAtPosition(myItemInt));

        String project = ((TextView) tableRow.findViewById(R.id.project)).getText().toString();
        String workRequest = ((TextView) tableRow.findViewById(R.id.work_request)).getText().toString();
        String startDate = ((TextView) tableRow.findViewById(R.id.start_date)).getText().toString();
        String status = ((TextView) tableRow.findViewById(R.id.status)).getText().toString();

          showWorkRequest(project, workRequest, startDate, status);

      }

  });

和xml代码:

<?xml version="1.0" encoding="utf-8"?>
<TableRow xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/tabRow1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    style="@style/BodyRow"
    android:gravity="center_horizontal" >

    <RelativeLayout 
    android:id="@+id/relativeLayout1"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"

    android:gravity="center_horizontal" >

    <TextView
        android:id="@+id/status"
        android:layout_width="wrap_content"
        style="@style/BodyText"
        android:layout_height="wrap_content"

        android:layout_alignParentRight="true"
         android:textColor="@color/textColor"
        android:text="TextView" />

    <TextView
        android:id="@+id/start_date"
        style="@style/HourText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="TextView"  android:textColor="@color/textColor" android:textSize="10sp"/>

    <TextView
        android:id="@+id/project"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_toRightOf="@+id/start_date"
        android:gravity="center_horizontal"
        style="@style/LeftHeaderText"
        android:text="TextView" android:layout_marginLeft="5dp"
        android:textColor="@color/textColor" android:textStyle="bold"/>

    <TextView
        android:id="@+id/work_request"
        android:layout_width="wrap_content"
        style="@style/BodyText"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/project"
        android:layout_below="@+id/project"
        android:text="TextView"
         android:textColor="@color/textColor" />

</RelativeLayout>
</TableRow>

我想我不能使用onClickListener,因为它通常被使用,因为我是extendind自定义适配器.在那种情况下,他们可能是一个问题

public void onItemClick(AdapterView<?> myAdapter, View myView, 
            int myItemInt, long mylng)

但是日志说:DashboardBean上的ClassCastException.

无论如何,我无法解决它.有人可以帮忙吗？

Answer 1

这ClassCastException是由您的以下行引起的OnItemClickListener:

TableRow tableRow = (TableRow) (mListView.getItemAtPosition(myItemInt));

那是因为你的适配器充满了DashboardBean实例.该getItemAtPosition方法返回属于适配器使用的数据结构的对象,而不是TableRow显示对象的图形小部件(我假设)的实例.只写:

DashboardBean board = (DashboardBean) (mListView.getItemAtPosition(myItemInt));

代替违规线就可以了.然后,您可以直接使用DashboardBean对象中的字段,而不是通过TextViews和类似的UI元素.