将搜索结果从片段传递给另一个片段

Question

我有片段执行搜索并从服务器获取结果并使用列表视图将结果发送到另一个片段展示它。结果它显示空列表什么都不显示片段搜索

public class Search extends Fragment implements View.OnClickListener {
EditText Drugname;
Button SendDrug;
private ProgressDialog plog;
private List<SearchAvailDrug> drugreq= new ArrayList<SearchAvailDrug> () ;
private CustomListAdapter adapter;
public Search() {
// Required empty public constructor
}
OnHeadlineSelectedListener mCallback;
// Container Activity must implement this interface
public interface OnHeadlineSelectedListener {
public void onArticleSelected(int position);
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mCallback = (OnHeadlineSelectedListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnHeadlineSelectedListener");
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_search, container, false);
Drugname=(EditText) view.findViewById(R.id.searchdrug);
SendDrug =(Button) view.findViewById(R.id.startdrug) ;
adapter = new CustomListAdapter(this, drugreq);
SendDrug.setOnClickListener(this);
return view;
}
@Override
public void onClick(View v) {
SendDataUp(Drugname.getText().toString());
}


@Override
public void onDetach() {
super.onDetach();
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
private void SendDataUp(final String Drugname){
Log.i("SendDataUp","Start");
String url = Urls.URL_AvailDrug;
//showing dialog box
plog = new ProgressDialog(getActivity());
plog.setIndeterminate(false);
plog.setMessage("Registration  Please wait ...");
plog.show();
// Start Using Volley
// Request a string response
StringRequest stringRequest = new StringRequest(Request.Method.POST, url,
new Response.Listener<String>() {
@RequiresApi(api = Build.VERSION_CODES.KITKAT)
@Override
public void onResponse(String response) {
hidePDialog();
String UserIdNum=null;
Log.v("Search",response);
try {
if (response.equalsIgnoreCase(String.valueOf(false)))
{
hidePDialog();
;

}
else
{
for (int i = 0; i < response.length(); i++) {
JSONArray RideJArray = new JSONArray(response);
SearchAvailDrug ride = new SearchAvailDrug();                                     ride.setDrugBrand(jpart.getString("BrandName"));                                      ride.setPharmcyNameAr(jpart.getString("phname_ar"));                                        ride.setPharmcyNameEn(jpart.getString("phname_ar"));
ride.setPhinfo(jpart.getString("info")); ;
ride.setLang(jpart.getDouble("lang"));
ride.setLat(jpart.getDouble("lat"));
drugreq.add(ride);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
adapter.notifyDataSetChanged();
Bundle args = new Bundle();
args.putParcelableArrayList("mylist", (ArrayList<? extends Parcelable>) drugreq);
Fragment fragment = new Listpage();
fragment.setArguments(args);
FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.content_nav_main, fragment);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();

// shownextpage();

}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
hidePDialog();
// Error handling
System.out.println("Something went wrong!");
error.printStackTrace();
Toast.makeText(getActivity(), "FAILED TO CONNECT",Toast.LENGTH_LONG).show();
}
})
{
@Override
public String getBodyContentType() {
return "application/x-www-form-urlencoded; charset=UTF-8";
}
@Override
protected Map<String, String> getParams()
{
Map<String, String> params = new HashMap<String, String>();
params.put("BrandName",Drugname);
return params;

}
};
// Add the request to the queue
int socketTimeout = 30000;//30 seconds - change to what you want
RetryPolicy policy = new DefaultRetryPolicy(socketTimeout, DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT);
stringRequest.setRetryPolicy(policy);
Volley.newRequestQueue(getActivity()).add(stringRequest);
}
private void shownextpage(){
Bundle args = new Bundle();
Fragment fragment = new Listpage();
fragment.setArguments(args);
FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.content_nav_main, fragment);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
}
private void hidePDialog() {
if (plog != null) {
plog.dismiss();
plog = null;
}
}
}

并在另一个片段列表视图中显示这是代码

public class Listpage extends Fragment {
private ListView listView;
private CustomListAdapter adapter;
private List<SearchAvailDrug> drugreq= new ArrayList<SearchAvailDrug>() ;
public Listpage() {
// Required empty public constructor
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_Listpage_list, container, false);
Bundle args = getArguments();
ArrayList<SearchAvailDrug>arrayList;
// arrayList = (ArrayList<SearchAvailDrug>)args.getParcelableArrayList("mylist");
drugreq = args.getParcelableArrayList("mylist");
adapter = new CustomListAdapter(this, drugreq);
listView = (ListView) view.findViewById(R.id.listpharmcy);
listView.setAdapter(adapter);
return  view;
}
}

它显示空列表视图的问题在我加载片段之后

Answer 1

在处理碎片和参数时，应遵循"newInstance"的建议，否则，Android操作系统可能会用null参数重新创建实例。

https://stackoverflow.com/a/9245510/6828464