erreur de liaison de données: la liaison de données n'existe pas

Question

J'ai essayé l'application listview pour utiliser le modèle mvvm.

mais j'ai des erreurs dans le studio android.

Je ne sais pas pourquoi ce projet ne fonctionne pas.

structure image

erreur:

1. Erreur: (18, 49) Erreur: package com.example.jhseo.flight_mvvm.databinding n'existe

2. Erreur: (30, 13) erreur: impossible de trouver la classe de symbole FlightActivityBinding

3. Erreur: L'exécution a échoué pour la tâche ': app: compileDebugJavaWithJavac'.

   java.lang.RuntimeException: Found data binding errors. ****/ data binding error ****msg:Identifiers must have user defined types from the XML file. viewModel is missing it file:E:\workspace_mobile\test\Flight-Mvvm\app\src\main\res\layout\flight_item.xml loc:15:27 - 15:35 ****\ data binding error ****

FlightActivity

public class FlightActivity extends AppCompatActivity implements FlightViewModel.DataListener{ 
private FlightActivityBinding binding; 
private FlightViewModel flightViewModel; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 

binding = DataBindingUtil.setContentView(this, R.layout.flight_activity); 
flightViewModel = new FlightViewModel(this, this); 
binding.setViewModel(flightViewModel); 

setupListVIew(binding.flightListView); 

@Override 
protected void onDestroy() { 
super.onDestroy(); 
} 

@Override 
public void onListChanged(ArrayList<Flight> flights) { 
FlightListAdapter adapter =(FlightListAdapter) binding.flightListView.getAdapter(); 
adapter.setFlights(flights); 
adapter.notifyDataSetChanged(); 
} 

private void setupListVIew(ListView flightListView) { 
FlightListAdapter adapter = new FlightListAdapter(this); 
flightListView.setAdapter(adapter); 
}   
} 

FlightViewModel

public class FlightViewModel { 

FlightFactory flightFactory; 
... 
public ObservableArrayList<Flight> flightList; 

private Context context; 
private DataListener dataListener; 
private Realm realm; 

public FlightViewModel(Context context, DataListener dataListener) { 
this.context = context; 
this.dataListener = dataListener; 
init(); 
loadData(); 
} 

public void setDataListener(DataListener dataListener) { this.dataListener = dataListener; } 

... 

public void searchByConditionInListAndSet() { 
RealmQuery<Flight> query = realm.where(Flight.class); 

if (!"".equals(terminal.get())) { 
query = query.equalTo("terminal", terminal.get()); 
} 
flightList.addAll(query.findAll().subList(0, (int) query.count())); 
if (dataListener != null) { 
dataListener.onListChanged(flightList); 
} 
... 
} 
public interface DataListener { 
void onListChanged(ArrayList<Flight> flights); 
} 
} 

ItemViewModel

public class ItemViewModel extends BaseObservable { 
private Flight flight; 
private Context context; 

public ItemViewModel(Flight flight, Context context) { 
this.flight = flight; 
this.context = context; 
} 
... 
public void onItemClick(View view) { 
//TODO: Detail Page 
//context.startActivity(); 
} 

public void setFlight(Flight flight) { 
this.flight = flight; 
notifyChange(); 
} 
} 

flight_activity.xml

flight_item.xml

<data> 
     <variable 
      name="itemModel" 
      type="com.example.jhseo.flight_mvvm.viewModel.ItemViewModel"/> 
    </data> 

    <LinearLayout android:orientation="horizontal" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:onClick="@{viewModel::onItemClick}"> 

     <LinearLayout 
      android:layout_width="50dp" 
      android:layout_height="wrap_content"> 

      <TextView 
       android:id="@+id/timeTextView" 
       android:layout_width="wrap_content" 
       android:layout_height="match_parent" 
       android:text="@{itemModel.time}" /> 
     </LinearLayout> 

     <LinearLayout 
      android:layout_width="100dp" 
      android:layout_height="wrap_content"> 

      <TextView 
       android:id="@+id/flightStateTextView" 
       android:layout_width="wrap_content" 
       android:layout_height="match_parent" 
       android:text="@{itemModel.flightState}" /> 
     </LinearLayout> 

     <LinearLayout 
      android:id="@+id/destinationi" 
      android:layout_width="80dp" 
      android:layout_height="wrap_content"> 

      <TextView 
       android:id="@+id/destinationTextView" 
       android:layout_width="wrap_content" 
       android:layout_height="match_parent" 
       android:text="@{itemModel.destination}" /> 
     </LinearLayout> 

     <LinearLayout 
      android:id="@+id/counterAndGatei" 
      android:layout_width="80dp" 
      android:layout_height="wrap_content"> 

      <TextView 
       android:id="@+id/counterAndGateTextView" 
       android:layout_width="wrap_content" 
       android:layout_height="match_parent" 
       android:text="@{itemModel.counterAndGate}" /> 
     </LinearLayout> 
     <LinearLayout 
      android:id="@+id/origini" 
      android:layout_width="70dp" 
      android:layout_height="wrap_content"> 

      <TextView 
       android:id="@+id/originTextView" 
       android:layout_width="wrap_content" 
       android:layout_height="match_parent" 
       android:text="@{itemModel.origin}" /> 
     </LinearLayout> 

     <LinearLayout 
      android:id="@+id/carouseli" 
      android:layout_width="40dp" 
      android:layout_height="wrap_content"> 

      <TextView 
       android:id="@+id/carouselTextView" 
       android:layout_width="wrap_content" 
       android:layout_height="match_parent" 
       android:text="@{itemModel.carousel}" /> 
     </LinearLayout> 

     <LinearLayout 
      android:id="@+id/exitDoori" 
      android:layout_width="70dp" 
      android:layout_height="wrap_content"> 

      <TextView 
       android:id="@+id/exitDoorTextView" 
       android:layout_width="wrap_content" 
       android:layout_height="match_parent" 
       android:text="@{itemModel.exitDoor}" /> 
     </LinearLayout> 
    </LinearLayout> 
</layout> 

Answer 1

L'erreur que vous avez obtenue est assez claire: il n'y a pas d'identifiant viewModel défini dans flight_item.xml.

changement

android:onClick="@{viewModel::onItemClick}" 

à

android:onClick="@{itemModel::onItemClick}" 

dans le fichier flight_item.xml.