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Ich bin relativ neu in Android-Entwicklung, und ich habe eine Anwendung erstellt, die Daten aus der Datenbank (MySQL) und (sollte) auf einer Karte in einem Fragment in Android geladen. Alle meine Java-Klassen zeigen keine Fehler an, aber wenn ich die Anwendung starte, bläst die Karte nicht innerhalb der RecyclerView auf. CardView nicht auf RecyclerView
Nachfolgend sind einige der Lösungen, die ich ohne Erfolg versucht:
CardView not shown in RecyclerView,
Android MySQL Tutorial to Perform Basic CRUD OperationHow to implement RecyclerView with CardView rows in a Fragment with TabLayout
Jede Hilfe würde geschätzt. Fragment, das die Klasse Ich verwende:
public class bloodBanks extends Fragment {
private RecyclerView recylerView;
private MyAdapter adapter;
private List<MyData>data_List;
private OnFragmentInteractionListener mListener;
public bloodBanks() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment bloodBanks.
*/
// TODO: Rename and change types and number of parameters
public static bloodBanks newInstance(String param1, String param2) {
bloodBanks fragment = new bloodBanks();
Bundle args = new Bundle();
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v= inflater.inflate(R.layout.fragment_blood_banks, container, false);
//perform(v);
recylerView=(RecyclerView) v.findViewById(R.id.recyle);
recylerView.setHasFixedSize(true);
data_List = new ArrayList<>();
adapter=new MyAdapter(getActivity(),data_List);
recylerView.setAdapter(adapter);
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
llm.setOrientation(LinearLayoutManager.VERTICAL);
recylerView.setLayoutManager(llm);
load_data_from_server(0);
return v;
}
private void load_data_from_server(final int id) {
AsyncTask<Integer,Void,Void> task = new AsyncTask<Integer, Void, Void>() {
@Override
protected Void doInBackground(Integer... params) {
OkHttpClient client= new OkHttpClient();
Request request = new Request.Builder()
.url("http://192.168.137.1:81/card.php?id="+id)
.build();
try {
Response response = client.newCall(request).execute();
JSONArray array = new JSONArray(response.body().string());
for (int i=0;i<array.length();i++){
JSONObject object=array.getJSONObject(i);
MyData data=new MyData(object.getInt("id"),object.getString("hospName"),object.getString("contact"));
data_List.add(data);
}
} catch(IOException e){
e.printStackTrace();
}catch (JSONException e){
System.out.println("No More Hospitals");
}
return null;
}
@Override
protected void onPostExecute(Void aVoid) {
adapter.notifyDataSetChanged();
}
};
task.execute(id);
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* 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);
}
}
Mein Adapter Klasse:
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder>{
private Context context;
private List<MyData> my_data;
public MyAdapter(Context context, List<MyData> my_data) {
this.context = context;
this.my_data = my_data;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.cards,parent,false);
return new ViewHolder(itemView);
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.hospName.setText(my_data.get(position).getHospName());
holder.contact.setText(my_data.get(position).getContact());
}
@Override
public int getItemCount() {
return my_data.size();
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView hospName;
public TextView contact;
public ViewHolder(View itemView){
super(itemView);
hospName=(TextView) itemView.findViewById(R.id.hosp);
contact=(TextView) itemView.findViewById(R.id.contact);
}
}
}
Datendefinitionen:
public class MyData {
private int id;
private String hospName,contact;
public MyData(int id, String hospName, String contact) {
this.id = id;
this.hospName = hospName;
this.contact = contact;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getHospName() {
return hospName;
}
public void setHospName(String hospName) {
this.hospName = hospName;
}
public String getContact() {
return contact;
}
public void setContact(String contact) {
this.contact = contact;
}
}
Cards.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.CardView
android:id="@+id/cdBanks"
android:layout_width="329dp"
android:layout_height="137dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.022"
android:layout_marginLeft="8dp"
app:layout_constraintLeft_toLeftOf="parent">
<RelativeLayout
android:layout_width="337dp"
android:layout_height="wrap_content">
<ImageView
android:id="@+id/hospPhoto"
android:layout_width="148dp"
android:layout_height="wrap_content"
android:src="@drawable/contacts_icon" />
<TextView
android:id="@+id/hosp"
android:layout_width="195dp"
android:layout_height="wrap_content"
android:layout_toRightOf="@+id/hospPhoto"
android:textSize="26sp"
tools:layout_editor_absoluteX="256dp"
tools:layout_editor_absoluteY="16dp" />
<TextView
android:id="@+id/contact"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/hosp"
android:layout_toRightOf="@+id/hospPhoto" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/contact"
android:layout_toRightOf="@+id/hospPhoto"
android:text="Blood Units: " />
</RelativeLayout>
</android.support.v7.widget.CardView>
</LinearLayout>
fragment_blood_banks. XML
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:card_view="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
card_view:context="layout.bloodBanks">
<android.support.v7.widget.RecyclerView
android:id="@+id/recyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
card_view:cardUSeCompatPadding="true"
card_view:cardElevation="5dp"
card_view:cardCornerRadius="5dp"
android:scrollbars="vertical"
android:layout_marginRight="6dp"
android:layout_marginLeft="6dp"
android:layout_marginTop="6dp"
/>
</android.support.constraint.ConstraintLayout>
Layout XML-Dateien ??? – Rahul
Bitte poste 'cards' und' fragment_blood_banks' XML-Codes. – Ircover
@Ircover Ich habe meine Frage bearbeitet, um die XML-Dateien einzuschließen. –