Android 未调用自定义适配器getView()方法

Android 未调用自定义适配器getView()方法,android,android-adapter,Android,Android Adapter,下面是我在其中为列表设置自定义适配器的片段代码 没有错误,但列表视图为空。我已经实现了getCount(),它在我的ArrayList中返回正确数量的项。我在logcat中没有看到(“Inside”,“GetView”) 片段 public class ServiceCarListFragment extends Fragment { private String url; private ArrayList<CarDetail> carDetailList = n

下面是我在其中为列表设置自定义适配器的片段代码

没有错误,但
列表视图
为空。我已经实现了
getCount()
,它在我的ArrayList中返回正确数量的项。我在logcat中没有看到
(“Inside”,“GetView”)

片段

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())));
        }

    }
}
公共类ServiceCarListFragment扩展了片段{
私有字符串url;
私有ArrayList carDetailList=新ArrayList();
专用适配器;
私有ListView-mList;
@凌驾
创建时的公共void(Bundle savedInstanceState){
//TODO自动生成的方法存根
super.onCreate(savedInstanceState);
url=getActivity().getIntent().getStringExtra(“url”);
新下载的cardeTail().execute(url);
}
@凌驾
创建视图上的公共视图(布局、充气机、视图组容器、,
Bundle savedInstanceState){
//TODO自动生成的方法存根
视图v=充气机。充气(R.layout.fragment\u service\u car\u list,容器,错误);
mList=(ListView)v.findViewById(R.id.list);
mList.setAdapter(适配器);
用于(CarDetail汽车:carDetailList){
//开始为每个学生加载图像
car.loadImage(适配器);
}
返回v;
}
类DownloadCarDetail扩展异步任务{
@凌驾
受保护的ArrayList doInBackground(字符串…参数){
//TODO自动生成的方法存根
ArrayList-carDetailList=JsonParser.parseJson(参数[0]);
返回卡德塔利斯特;
}
@凌驾
PostExecute上受保护的void(ArrayList carDetailList){
//TODO自动生成的方法存根
ServiceCarListFragment.this.carDetailList=carDetailList;
Log.d(“dccs”,String.valueOf(serviceCalistfragment.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;
    }

}
公共类CarListAdapter扩展了BaseAdapter{
private ArrayList items=new ArrayList();
私人语境;
公共CarListAdapter(上下文、ArrayList项){
this.context=上下文;
这个项目=项目;
}
@凌驾
public int getCount(){
//TODO自动生成的方法存根
返回items.size();
}
@凌驾
公共对象getItem(int位置){
//TODO自动生成的方法存根
返回项目。获取(位置);
}
@凌驾
公共长getItemId(int位置){
//TODO自动生成的方法存根
返回位置;
}
@凌驾
公共视图getView(int位置、视图转换视图、视图组父视图){
//TODO自动生成的方法存根
Log.d(“内部”、“获取视图”);
LayoutInflater mInflater=(LayoutInflater)context.getSystemService(Activity.LAYOUT\u INFLATER\u SERVICE);
ViewHolder=null;
CarDetail car=items.get(位置);
if(convertView==null){
convertView=mInflater.充气(R.layout.car\u list\u row,空);
holder=新的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(支架);
}否则{
holder=(ViewHolder)convertView.getTag();
}
holder.tvCarName.setText(car.getCarName());
if(car.getImage()!=null){
holder.imgCar.setImageBitmap(car.getImage());
}否则{
//我的默认图像
holder.imgCar.setImageResource(R.drawable.ic\u action\u调用);
}
返回视图;
}
静态类视窗夹{
文本视图tvCarName;
TextView tvDailyPriceValue;
TextView tvWeeklyPriceValue;
图像视图imgCar;
}
}

未调用getView的唯一原因是:

  • getCount
    返回0
  • 您忘了在
    列表视图上调用
    setAdapter
  • 如果
    列表视图
    的可见性(或其容器的可见性)已消失
    。感谢@TaynãBonaldo的宝贵意见
  • ListView
    未附加到任何视口布局。也就是说,
    mListView=newlistview(…)
    在不使用
    myLayout.addView(mListView)
    的情况下使用
  • onpostExecute
    中,创建
    CarListAdapter
    的新实例后,我建议您将新实例更新到您的
    列表视图中。你确实需要再打一次电话

     mList.setAdapter(adapter);
    
    编辑:
    setAdapter
    应始终在ui线程上调用,以避免意外行为

    Edit2:

    这同样适用于
    RecyclerView
    。确保

    • 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
      setAdapter
    • 小部件的可见性必须设置为
      VISIBLE

    构造函数中缺少超类。请参见下面的示例:

    public AppDataAdapter(Activity a, int textViewResourceId, ArrayList<AppData> entries) {
        super(a, textViewResourceId, entries);
        this.entries = entries;
        this.activity = a;
    }
    
    public-AppDataAdapter(活动a、int-textViewResourceId、ArrayList条目){
    super(a,textViewResourceId,条目);
    this.entries=条目;
    本活动=a;
    }
    
    您一直在做的是

    在适配器中

    public CarListAdapter(Context context , ArrayList<CarDetail> items) {
    
        this.context = context;
        this.items = items;
    
    }
    
    我希望您将使用
    FragmentActivity

    adapter = new CarListAdapter(getActivity(),ServiceCarListFragment.this.carDetailList);
    
    adapter = new CarListAdapter(YOUR_ACTIVITY_CONTEXT, carDetailList);
    
    mList = (ListView)v.findViewById(R.id.list);
    mList.setAdapter(adapter);
    
    mList = (ListView)v.findViewById(R.id.list);
    mList.post(new Runnable() {
        public void run() {
            mList.setAdapter(adapter);
        }
    });
    
    adapter.getCount();