Question

我在收到Firebase时遇到此错误，请在哪里出错。我需要你的帮助我是Firebase的新手。我真的不知道什么是错的，代码在我看来是正常的。

错误：

E/AndroidRuntime: FATAL EXCEPTION: main
  Process: com.example.murilo.firebaseimagemtexo, PID: 11124
  com.google.firebase.database.DatabaseException: Can't convert object of type java.lang.String to type com.example.murilo.firebaseimagemtexo.Movie
      at com.google.android.gms.internal.zzanp.zze(Unknown Source)
      at com.google.android.gms.internal.zzanp.zzb(Unknown Source)
      at com.google.android.gms.internal.zzanp.zza(Unknown Source)
      at com.google.firebase.database.DataSnapshot.getValue(Unknown Source)
      at com.example.murilo.firebaseimagemtexo.BdFire.fetechUpdate(BdFire.java:84)
      at com.example.murilo.firebaseimagemtexo.BdFire$1.onChildAdded(BdFire.java:50)
      at com.google.android.gms.internal.zzajg.zza(Unknown Source)
      at com.google.android.gms.internal.zzalg.zzcxk(Unknown Source)
      at com.google.android.gms.internal.zzalj$1.run(Unknown Source)
      at android.os.Handler.handleCallback(Handler.java:739)
      at android.os.Handler.dispatchMessage(Handler.java:95)
      at android.os.Looper.loop(Looper.java:148)
      at android.app.ActivityThread.main(ActivityThread.java:5451)
      at java.lang.reflect.Method.invoke(Native Method)
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

课堂电影：

public class Movie {
private  String nome;
private  String url;

public Movie() {
}

public String getNome() {
    return nome;
}

public void setNome(String nome) {
    this.nome = nome;
}

public String getUrl() {
    return url;
}

public void setUrl(String url) {
    this.url = url;
}}

BdFire类：

public class BdFire {
Context c;
ListView lv;
ArrayList<Movie>movies = new ArrayList<>();
CustomAdapter adapter;
FirebaseDatabase database;
DatabaseReference myRef;

public BdFire(Context c, ListView lv) {
    this.c = c;
    this.lv = lv;
    database = FirebaseDatabase.getInstance();
    myRef = database.getReference("Movie");
}

//save
public  void saveOnline(String nome,String url){

    Movie m = new Movie();

    m.setNome(nome);
    m.setUrl(url);

    myRef.push().setValue(m);
}

//retrive

public  void refreshDate(){
    myRef.addChildEventListener(new ChildEventListener() {
        @Override
        public void onChildAdded(DataSnapshot dataSnapshot, String s) {
            fetechUpdate(dataSnapshot);
        }

        @Override
        public void onChildChanged(DataSnapshot dataSnapshot, String s) {
            fetechUpdate(dataSnapshot);
        }

        @Override
        public void onChildRemoved(DataSnapshot dataSnapshot) {

        }

        @Override
        public void onChildMoved(DataSnapshot dataSnapshot, String s) {

        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });


}

public  void fetechUpdate(DataSnapshot dataSnapshot){
        movies.clear();

    for (DataSnapshot ds:dataSnapshot.getChildren())
    {
        Movie m = new Movie();
        System.out.println(ds.getValue());
        m.setNome(ds.getValue(Movie.class).getNome());
        m.setUrl(ds.getValue(Movie.class).getUrl());

        movies.add(m);

    }
    if (movies.size()>0){
        adapter = new CustomAdapter(c,movies);
        lv.setAdapter(adapter);

    }

}}

Class CustmAdapter：

public class CustomAdapter extends BaseAdapter {

Context c;
ArrayList<Movie> movies;
LayoutInflater inflater;

public CustomAdapter(Context c, ArrayList<Movie> movies) {
    this.c = c;
    this.movies = movies;
}

@Override
public int getCount() {
    return movies.size();
}

@Override
public Object getItem(int position) {
    return movies.get(position);
}

@Override
public long getItemId(int position) {
    return position;
}

@Override
public View getView(int postion, View convertView, ViewGroup viewGroup) {

    if (inflater == null){
        inflater=(LayoutInflater) c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    }
    if(convertView == null){
     convertView = inflater.inflate(R.layout.model,viewGroup,false);
    }

    MyViewHolder holder = new MyViewHolder(convertView);
    holder.nomeTxt.setText(movies.get(postion).getNome());
    PicassoCliente.downloadImage(c,movies.get(postion).getUrl(),holder.img);


    return convertView;
}}

FIREBASE

Answer 1

saveOnline()：myRef.push().setValue(m)中的此声明表明myRef的孩子是Movie的实例。在refreshDate()中，您向ChildEventListener添加了myRef。 onChildAdded()的数据快照为Movie。在fetechUpdate中，您无法循环数据快照的子项以构建电影列表。孩子是Movie的字符串成员。

Helpe无法将java.lang.String类型的对象转换为type

1 个答案: