Android 自定义适配器不工作
我的Android 自定义适配器不工作,android,Android,我的列表视图有一个自定义适配器。它在setAdapter处为我提供NullPointerException。我已经检查了我的代码好几次,但都不知道是什么导致了NPE。以下是相关的代码片段: 活动: ListView mListView; Vector<DashboardBean> dashboardBean= new Vector<DashboardBean>(); MyCustomAdapter adapter; adapter = new MyCustomAdapt
列表视图有一个自定义适配器。它在setAdapter
处为我提供NullPointerException
。我已经检查了我的代码好几次,但都不知道是什么导致了NPE。以下是相关的代码片段:
活动:
ListView mListView;
Vector<DashboardBean> dashboardBean= new Vector<DashboardBean>();
MyCustomAdapter adapter;
adapter = new MyCustomAdapter(MyDashboardActivity.this,
R.layout.testdashboard_row, dashboardBean);
adapter.clear();
dashboardBean.add(new DashboardBean(projects, workRequests, status));
mListView.setAdapter(adapter);
自定义适配器:
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.status = (TextView) row.findViewById(R.id.status);
row.setTag(holder);
}
else
{
holder=(MyStringReaderHolder) row.getTag();
}
DashboardBean mrb = data.elementAt(position);
holder.project.setText(mrb.project);
holder.workRequest.setText(mrb.workRequest);
holder.status.setText(mrb.status);
return row;
}
static class MyStringReaderHolder
{
TextView project, workRequest, startDate, status, actualHours;
}
}
公共类MyCustomAdapter扩展了ArrayAdapter{
语境;
国际布局资源;
仪表板bean currentMRB;
矢量数据;
公共MyCustomAdapter(上下文、int-layoutResourceId、向量数据)
{
超级(上下文、布局资源ID、数据);
this.layoutResourceId=layoutResourceId;
this.context=context;
这个数据=数据;
}
@凌驾
公共视图getView(int位置、视图转换视图、视图组父视图){
视图行=转换视图;
mystringraderholder;
if(行==null)
{
LayoutInflater充气器=((活动)上下文)。getLayoutInflater();
行=充气机。充气(layoutResourceId,父级,false);
holder=新MyStringReaderHolder();
holder.project=(TextView)row.findViewById(R.id.project);
holder.workRequest=(TextView)row.findViewById(R.id.work\u请求);
holder.status=(TextView)row.findViewById(R.id.status);
row.setTag(支架);
}
其他的
{
holder=(MyStringReaderHolder)行。getTag();
}
DashboardBean mrb=data.elementAt(位置);
holder.project.setText(mrb.project);
holder.workRequest.setText(mrb.workRequest);
holder.status.setText(mrb.status);
返回行;
}
静态类MyStringReaderHolder
{
TextView项目、工作请求、开始日期、状态、实际小时数;
}
}
有人能帮忙吗?在您的“活动”代码段中,您从未为mListView
赋值:
ListView mListView; //initialize me please :)
因此,它为null,并且将始终抛出NullPointerException
。也许您已经在xml中定义了一些东西,并且希望调用findViewById(int)
嗯,它被初始化了。但是,请输入错误的id。非常感谢您指出:)
ListView mListView; //initialize me please :)
mListView = (ListView) findViewById(R.id.theListViewId);