android – 自定义适配器getView()方法未被调用
作者:互联网
这是片段的代码,我在其中为列表设置自定义适配器.
没有错误,但ListView为空.我已经实现了getCount(),它返回了我的ArrayList中正确数量的项目.我没有在logcat中看到(“Inside”,“GetView”)
分段
public class ServiceCarListFragment extends Fragment {
private String url;
private ArrayList<CarDetail> carDetailList = new ArrayList<CarDetail>();
private CarListAdapter adapter;
private ListView mList;
@Override
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
url = getActivity().getIntent().getStringExtra("url");
new DownloadCarDetail().execute(url);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub
View v = inflater.inflate(R.layout.fragment_service_car_list, container, false);
mList = (ListView) v.findViewById(R.id.list);
mList.setAdapter(adapter);
for (CarDetail car : carDetailList) {
// START LOADING IMAGES FOR EACH STUDENT
car.loadImage(adapter);
}
return v;
}
class DownloadCarDetail extends AsyncTask<String, String, ArrayList<CarDetail>> {
@Override
protected ArrayList<CarDetail> doInBackground(String... params) {
// TODO Auto-generated method stub
ArrayList<CarDetail> carDetailList = JsonParser.parseJson(params[0]);
return carDetailList;
}
@Override
protected void onPostExecute(ArrayList<CarDetail> carDetailList) {
// TODO Auto-generated method stub
ServiceCarListFragment.this.carDetailList = carDetailList;
Log.d("dccs", String.valueOf(ServiceCarListFragment.this.carDetailList.size()));
adapter = new CarListAdapter(getActivity(), ServiceCarListFragment.this.carDetailList);
Log.d("dccs", String.valueOf((adapter.getCount())));
}
}
}
CustomAdapter
public class CarListAdapter extends BaseAdapter {
private ArrayList<CarDetail> items = new ArrayList<CarDetail>();
private Context context;
public CarListAdapter(Context context, ArrayList<CarDetail> items) {
this.context = context;
this.items = items;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return items.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return items.get(position);
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
Log.d("Inside", "GetView");
LayoutInflater mInflater = (LayoutInflater) context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
ViewHolder holder = null;
CarDetail car = items.get(position);
if (convertView == null) {
convertView = mInflater.inflate(R.layout.car_list_row, null);
holder = new ViewHolder();
holder.tvCarName = (TextView) convertView.findViewById(R.id.tvCarName);
holder.tvDailyPriceValue = (TextView) convertView.findViewById(R.id.tvWeeklyPriceValue);
holder.tvWeeklyPriceValue = (TextView) convertView.findViewById(R.id.tvWeeklyPriceValue);
holder.imgCar = (ImageView) convertView.findViewById(R.id.imgCar);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.tvCarName.setText(car.getCarName());
if (car.getImage() != null) {
holder.imgCar.setImageBitmap(car.getImage());
} else {
// MY DEFAULT IMAGE
holder.imgCar.setImageResource(R.drawable.ic_action_call);
}
return convertView;
}
static class ViewHolder {
TextView tvCarName;
TextView tvDailyPriceValue;
TextView tvWeeklyPriceValue;
ImageView imgCar;
}
}
解决方法:
getView未被调用的唯一原因是:
> getCount返回0.
>你忘了在ListView上调用setAdapter.
>如果ListView的可见性(或其容器的可见性)为GONE.感谢@TaynãBonaldo的宝贵意见.
> ListView未附加到任何视口布局.也就是说,使用mListView = new ListView(…)而不使用myLayout.addView(mListView).
在onPostExcute中,在创建CarListAdapter的新实例后,我建议您将新实例更新到ListView.确实你需要再次打电话
mList.setAdapter(adapter);
编辑:应始终在ui线程上调用setAdapter,以避免意外行为
EDIT2:
这同样适用于RecyclerView.确保这一点
> getItemCount返回的值大于0(通常是数据集大小)
>必须在UI线程上调用setLayoutManager和setAdapter
>必须将窗口小部件的可见性设置为可见
标签:android-adapter,android 来源: https://codeday.me/bug/20190911/1804098.html