自定义适配器从片段获取空上下文

Question

我正在使用选项卡布局。我正在从live DB获取数据，以便在listview中显示信息。为此，我使用CustomAdapter。arraylist中正确获取的值。一旦将Arraylist数据传递给CustomAdapter，则上下文将出现null异常。如何将片段的上下文传递给自定义适配器。

自定义适配器构造函数

/**Here in Constructor, context getting null value. App Crashing*/
public HotelCustomAdapter(Context hotelMaster, int textViewResourceId,ArrayList<GetSetOffers> hotelLists) {
    super(hotelMaster,textViewResourceId, hotelLists);
    hotelList=hotelLists;
    context=hotelMaster;
    inflater = ( LayoutInflater )context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

已编辑：

碎片

从片段中，我调用AsyncTask类从云获取数据。从postExecute，我将Arraylist传递给fragment方法。此时，上下文为空。如何修复此问题。

片段类

public class OneFragment extends Fragment implements View.OnClickListener{
View view;
Button ok;
TextView text;
public ListView list;
HotelCustomAdapter hca;
ArrayList<GetSetOffers> temp;
Context context;
public OneFragment() {
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    ScrollView scroller = new ScrollView(getActivity());

    view = inflater.inflate(R.layout.fragment_one, container, false);
    ok = (Button) view.findViewById(R.id.ok);
    text = (TextView)view.findViewById(R.id.text);
    list = (ListView) view.findViewById(R.id.list);
    ok.setOnClickListener(this);
    context=view.getContext(); // Here the context is assigned
    new AsyncHotel(getActivity()).execute("19");
    return view;
}

//After the value got from postExecute, it was showing null to the context
public void getAdapterView(ArrayList<GetSetOffers> hotelList){
    //temp=hotelList;
    hca=new HotelCustomAdapter(context,R.layout.hotel_custom_listview,hotelList);
    list.setAdapter(hca);
}

@Override
public void onClick(View v) {
    switch (v.getId()) {
        case R.id.ok:
            text.setText("Y You Clicked.?");
    //hca=new HotelCustomAdapter(getActivity(),R.layout.hotel_custom_listview,temp);
    //list.setAdapter(hca);     // tried this
            break;
    }
}

}

postExecute（）方法

@Override
protected void onPostExecute(String result) {
    try {
        root = new JSONObject(result);
        validation = root.getInt("response");
        JSONArray data = root.getJSONArray("data");

        if (validation == 1) {
            for (int i = 0; i < data.length(); i++) {
                hgs = new GetSetOffers(); 
                hgs.setOfferTitle(data.getJSONObject(i).getString("hotel_name"));
                hgs.setOfferDescrip(data.getJSONObject(i).getString("city"));
                hgs.setOfferToDt(data.getJSONObject(i).getString("hotel_name"));

                hotelList.add(hgs);
            }
            OneFragment one=new OneFragment(); // I think here I am doing wrong
            one.getAdapterView(hotelList);
        }
  } catch (JSONException e) {
        e.printStackTrace();
    }
}

我认为将值从AsyncTask postExecute方法传递到Fragment是错误的。片段上下文再次为null。

上下文是全局声明的。在调用AsyncTask类之前，上下文变量被分配给Active。该片段上下文现在有值。AsyncTask类完成其任务，然后将列表传递给片段，方法是在postExecute（）方法中为该片段创建新对象，然后将该列表传递给自定义数组适配器，并且上下文为空。请参阅图像。

我再次尝试将收到的列表分配给片段中的全局变量。然后单击按钮后，我尝试将列表传递给自定义阵列适配器。现在，上下文具有值，列表更改为空，即使该列表已分配给全局变量

Answer 1

//After the value got from postExecute, it was showing null to the context 
public void getAdapterView(ArrayList<GetSetOffers> hotelList){
    hca=new HotelCustomAdapter(getActivity(),R.layout.hotel_custom_listview,hotelList);
    list.setAdapter(hca);
} 

仅执行此更改。无需更改适配器中的上下文。它会起作用的。

Answer 2

请试试这个-

//After the value got from postExecute, it was showing null to the context 
public void getAdapterView(ArrayList<GetSetOffers> hotelList){
    hca=new HotelCustomAdapter(getActivity(),R.layout.hotel_custom_listview,hotelList);
    list.setAdapter(hca);
} 

并且在适配器类中也这样做。

/**Here in Constructor, context getting null value. App Crashing*/ 
Activity context;
public HotelCustomAdapter(Activity hotelMaster, int textViewResourceId,ArrayList<GetSetOffers> hotelLists) { 
    super(hotelMaster,textViewResourceId, hotelLists); 
    hotelList=hotelLists; 
    this.context=hotelMaster; 
    inflater = ( LayoutInflater )context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
} 

Answer 3

因为这样的问题，我开始这样做：

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
           View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item, parent, false);
           ...
        }