Objekt des Typs java.lang.String kann nicht in Typ konvertiert werden - Firebase Fehler

Question

sein Firebase Fehler Ich kann es nicht bekommen Bitte hilf mir zu lösen und erzähle mir den Grund, warum es passiert. Für Englisch Entschuldigung und versuchen Sie es beendet

E/AndroidRuntime: FATAL EXCEPTION: main 
       Process: com.example.kunalgharate.weedon, PID: 16793 
       com.google.firebase.database.DatabaseException: Can't convert object of type java.lang.String to type com.example.kunalgharate.weedon.Friends 
        at com.google.android.gms.internal.zg.zzb(Unknown Source) 
        at com.google.android.gms.internal.zg.zza(Unknown Source) 
        at com.google.firebase.database.DataSnapshot.getValue(Unknown Source) 
        at com.firebase.ui.database.ClassSnapshotParser.parseSnapshot(ClassSnapshotParser.java:22) 
        at com.firebase.ui.database.ObservableSnapshotArray.getObject(ObservableSnapshotArray.java:160) 
        at com.firebase.ui.database.CachingObservableSnapshotArray.getObject(CachingObservableSnapshotArray.java:40) 
        at com.firebase.ui.database.FirebaseRecyclerAdapter.getItem(FirebaseRecyclerAdapter.java:180) 
        at com.firebase.ui.database.FirebaseRecyclerAdapter.onBindViewHolder(FirebaseRecyclerAdapter.java:217) 
        at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:6482) 
        at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:6515) 
        at android.support.v7.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:5458) 
        at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5724) 
        at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5563) 
        at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5559) 
        at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2229) 
        at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1556) 
        at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1516) 
        at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:608) 
        at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3693) 
        at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3410) 
        at android.support.v7.widget.RecyclerView.consumePendingUpdateOperations(RecyclerView.java:1710) 
        at android.support.v7.widget.RecyclerView$1.run(RecyclerView.java:346) 
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:871) 
        at android.view.Choreographer.doCallbacks(Choreographer.java:683) 
        at android.view.Choreographer.doFrame(Choreographer.java:616) 
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:857) 
        at android.os.Handler.handleCallback(Handler.java:751) 
        at android.os.Handler.dispatchMessage(Handler.java:95) 
        at android.os.Looper.loop(Looper.java:154) 
        at android.app.ActivityThread.main(ActivityThread.java:6123) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:757) 

Anwendung zu lösen.

Aktivität Haupt

import android.content.Context; 
import android.content.Intent; 
import android.os.Build; 
import android.support.design.widget.TabLayout; 
import android.support.v4.view.ViewPager; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.support.v7.widget.LinearLayoutManager; 
import android.support.v7.widget.RecyclerView; 
import android.support.v7.widget.Toolbar; 
import android.util.Log; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.widget.TextView; 
import android.widget.Toast; 

import com.firebase.ui.database.FirebaseRecyclerAdapter; 
import com.google.firebase.auth.FirebaseAuth; 
import com.google.firebase.database.DatabaseReference; 
import com.google.firebase.database.FirebaseDatabase; 
import com.squareup.picasso.Picasso; 

import de.hdodenhof.circleimageview.CircleImageView; 

public class MainActivity extends AppCompatActivity { 
    private FirebaseAuth mAuth; 
    RecyclerView mSubsList; 
    DatabaseReference mFriendsDatabase; 
    DatabaseReference mUsersDatabase; 
    private String mCurrent_user_id; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     Toolbar toolbar = findViewById(R.id.main_page_toolbar); 
     setSupportActionBar(toolbar); 
     getSupportActionBar().setTitle("WeedON"); 
     mAuth = FirebaseAuth.getInstance(); 
     mCurrent_user_id = mAuth.getCurrentUser().getUid(); 
     mSubsList =findViewById(R.id.subscribes_list); 
     mSubsList.setHasFixedSize(true); 
     mSubsList.setLayoutManager(new LinearLayoutManager(this)); 


     mFriendsDatabase = FirebaseDatabase.getInstance().getReference().child("subscribers").child(mCurrent_user_id); 
     mFriendsDatabase.keepSynced(true); 
     mUsersDatabase = FirebaseDatabase.getInstance().getReference().child("Users"); 
     mUsersDatabase.keepSynced(true); 




    } 

    private void signOut() { 
     mAuth.signOut(); 
    } 


    @Override 
    protected void onStart() { 
     super.onStart(); 

     FirebaseRecyclerAdapter<Friends,MainViewHolder> firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<Friends,MainViewHolder>(


       Friends.class, 
       R.layout.single_service_layout, 
       MainViewHolder.class, 
       mFriendsDatabase 
       ) 
     { 
      @Override 
      protected void populateViewHolder(MainViewHolder viewHolder, Friends model, int position) { 



      } 
     }; 

     mSubsList.setAdapter(firebaseRecyclerAdapter); 
     } 





    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     super.onCreateOptionsMenu(menu); 

     getMenuInflater().inflate(R.menu.main_menu, menu); 

     return true; 
    } 


    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     super.onOptionsItemSelected(item); 

     if(item.getItemId() == R.id.main_logout_btn){ 

      // mUserRef.child("online").setValue(ServerValue.TIMESTAMP); 

      signOut(); 
      Intent intent = new Intent(this, LoginActivity.class); 
      startActivity(intent); 
      finish(); 
     // sendToStart(); 

     } 

     if(item.getItemId() == R.id.main_settings_btn){ 

      Intent settingsIntent = new Intent(MainActivity.this, SettingsActivity.class); 
      startActivity(settingsIntent); 

     } 

     if(item.getItemId() == R.id.main_all_btn){ 

      Intent settingsIntent = new Intent(MainActivity.this, AllServicesActivity.class); 
      startActivity(settingsIntent); 

     } 

     return true; 
    } 

    public static class MainViewHolder extends RecyclerView.ViewHolder{ 

     View mView; 

     public MainViewHolder(View itemView) { 
      super(itemView); 

      mView =itemView; 
     } 


    } 



} 

Database Screenshot

enter image description here

seine Nicht-Layout-Fehler oder Fehlercode zeigt, was soll ich tun?

Answer 1

Um diese Nachrichten anzuzeigen, bitte den folgenden Code verwenden:

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference(); 
DatabaseReference uidRef = rootRef.child("subscribers").child(mCurrent_user_id); 
ValueEventListener eventListener = new ValueEventListener() { 
    @Override 
    public void onDataChange(DataSnapshot dataSnapshot) { 
     for(DataSnapshot ds : dataSnapshot.getChildren()) { 
      String message = ds.getValue(String.class); 
      Log.d("TAG", message); 
     } 
    } 

    @Override 
    public void onCancelled(DatabaseError databaseError) {} 
}; 
uidRef.addListenerForSingleValueEvent(eventListener); 

Answer 2

von in Ihrer Datenbank suchen kann ich Ihre mFriendsDatabase DatabseReference Punkte, um einige ‚String‘ Werte und erzählen Sie Ihren firebaseRecyclerAdapter sehen, dass diejenigen sind vom Typ 'Friends, deshalb wird die Ausnahme ausgelöst.Meistens machen Sie einen Fehler, während Sie den Wert in der Datenbank speichern, anstatt ein Friends-Objekt zu speichern, speichern Sie einen String-Wert. Wenn das nicht der Fall ist, können Sie Ihre ändern firebaseRecyclerAdapter zu diesem ...

FirebaseRecyclerAdapter<String,MainViewHolder> firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<String,MainViewHolder>(


      String.class, 
      R.layout.single_service_layout, 
      MainViewHolder.class, 
      mFriendsDatabase 
      ) 
    { 
     @Override 
     protected void populateViewHolder(MainViewHolder viewHolder, String mString, int position) { 
      Log.d("TAG",mString); 
     } 
    }; 

    mSubsList.setAdapter(firebaseRecyclerAdapter);