Android com.google.firebase.database.DatabaseException:Can'；t将java.lang.String类型的对象转换为Recension

我有一个很多人都有过的问题，但我不明白如何才能摆脱它。请帮我拿我的箱子，不要标为复制品。我有一个与firebase链接的回收视图。 我必须检索“修订”后面的所有项目。 所有项目都有一些文本视图，其中写入了数据库中的一些字符串。但是，当我尝试检索数据库中的项目时，会出现以下错误：

这是我的最新课程：

public class Recensione {
private String Commento;
private String Rating;
private String Username;
private String Data;

public String getData() {
    return Data;
}

public void setData(String data) {
    Data = data;
}

public String getUsername() {
    return Username;
}

public void setUsername(String username) {
    Username = username;
}

public String getRating() {
    return Rating;
}

public void setRating(String rating) {
    Rating = rating;
}


public String getCommento() {
    return Commento;
}

public void setCommento(String commento) {
    Commento = commento;
}}

这里是我的占位符片段/DisplayStudio.class：

public static class PlaceholderFragment extends Fragment implements OnMapReadyCallback {

    private GoogleMap googleMapa;

    /**
     * The fragment argument representing the section number for this
     * fragment.
     */
    private static final String ARG_SECTION_NUMBER = "section_number";

    public PlaceholderFragment() {
    }

    /**
     * Returns a new instance of this fragment for the given section
     * number.
     */
    public static DisplayStudio.PlaceholderFragment newInstance(int sectionNumber) {
        DisplayStudio.PlaceholderFragment fragment = new DisplayStudio.PlaceholderFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        return fragment;
    }

    RecyclerView rv;
    MyCommentsAdapter adapter;
    ArrayList<Recensione> recensioni = new ArrayList<>();
    DatabaseReference mDatabase;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        Bundle bl = getArguments();
        if (getArguments().getInt(ARG_SECTION_NUMBER)==1)
        {

            View rootView = inflater.inflate(R.layout.fragment_profilo, container, false);

            Intent intent = getActivity().getIntent();

            String desc = intent.getStringExtra("Desc");
            final String names = intent.getStringExtra("Nome");

            TextView test = (TextView) rootView.findViewById(R.id.nome);
            TextView descr = (TextView) rootView.findViewById(R.id.desc);
            TextView key = (TextView) rootView.findViewById(R.id.key);

            test.setText(names);
            descr.setText(desc);

            String MyKey = bl.getString(MY_STUDIO_KEY);
            key.setText(MyKey);

        return rootView;
        }
        else if(getArguments().getInt(ARG_SECTION_NUMBER)==2)
        {


            Intent intent = getActivity().getIntent();
            final String names = intent.getStringExtra("Nome");

            //INITIALIZE FIREBASE
            mDatabase = FirebaseDatabase.getInstance().getReference().child("Studi").child(names).child("valutazioni").child("recensioni");
            mDatabase.keepSynced(true);
            /* Ricarica tutte le opinioni */
            refreshData();
            View rootView = inflater.inflate(R.layout.fragment_opinioni, container, false);
            rv = (RecyclerView) rootView.findViewById(R.id.MyRecView2s);

            Recensione rc = new Recensione();
            rc.setUsername("Luca");
            rc.setCommento("Non male, da app");
            rc.setRating("10");
            rc.setData("oggi");
            //ci vuole il push prima del setvalue
            mDatabase.child(names).setValue(rc);
            rv.setLayoutManager(new LinearLayoutManager(getActivity()));

            return rootView;
        }
        else
        {
            View rootView = inflater.inflate(R.layout.fragment_maps, container, false);
            SupportMapFragment mapFragment = SupportMapFragment.newInstance();
            getChildFragmentManager().beginTransaction().replace(R.id.map , mapFragment).commit();
            mapFragment.getMapAsync(this);


            if (mapFragment == null) {
                getChildFragmentManager().beginTransaction().replace(R.id.map , mapFragment).commit();
                mapFragment.getMapAsync(this);
            }


            return rootView;
        }
    }
    private void getUpdates(DataSnapshot dataSnapshot){

        recensioni.clear();

        for (DataSnapshot ds : dataSnapshot.getChildren()){
            Recensione s=new Recensione();
            s.setUsername(ds.getValue(Recensione.class).getUsername());
            s.setCommento(ds.getValue(Recensione.class).getCommento());
            s.setRating(ds.getValue(Recensione.class).getRating());
            s.setData(ds.getValue(Recensione.class).getData());
            recensioni.add(s);
        }

        if(recensioni.size()>0){
            adapter=new MyCommentsAdapter(getActivity(), recensioni);
            rv.setAdapter(adapter);
        }else {
            Toast.makeText(getActivity(),"NON CI SONO ANCORA OPINIONI.", Toast.LENGTH_LONG).show();

        }
    }
    //RETRIEVE
    private void refreshData(){

        mDatabase.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(DataSnapshot dataSnapshot, String s) {
                getUpdates(dataSnapshot);
            }

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

            @Override
            public void onChildRemoved(DataSnapshot dataSnapshot) {

            }

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

            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });

    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        googleMapa = googleMap;
        Intent intent = getActivity().getIntent();

        final String names = intent.getStringExtra("Nome");

        String posizione1 = intent.getStringExtra("Posizione1");
        String posizione2 = intent.getStringExtra("Posizione2");

        try
        {
            //Toast.makeText(MapsActivity.this,posizione1 + " " + posizione2 , Toast.LENGTH_LONG).show();   //not a double
            Double protein = Double.parseDouble(posizione1);
            Double protein2 = Double.parseDouble(posizione2);
             LatLng sydney = new LatLng(protein,protein2);                                                                           //custom icon in drawable
            googleMap.addMarker(new MarkerOptions().position(sydney).title(names)/*.icon(BitmapDescriptorFactory.fromResource(R.drawable.cast_abc_scrubber_control_off_mtrl_alpha))*/);
            googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(sydney, 12.0f));

        }
        catch(NumberFormatException e)
        {
            //  Toast.makeText(DisplayStudio.this, e.toString() , Toast.LENGTH_LONG).show();   //not a double
        }



    }
}

/**
 * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
 * one of the sections/tabs/pages.
 */
public class SectionsPagerAdapter extends FragmentPagerAdapter {

    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {
        // getItem is called to instantiate the fragment for the given page.
        // Return a PlaceholderFragment (defined as a static inner class below).
        return DisplayStudio.PlaceholderFragment.newInstance(position + 1);
    }

    @Override
    public int getCount() {
        // Show 3 total pages.
        return 3;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0:
                return "PROFILO";
            case 1:
                return "OPINIONI";
            case 2:
                return "MAPS";
        }
        return null;
    }
}}

public静态类PlaceholderFragment扩展了mapreadycallback上的片段实现{
私人谷歌地图谷歌地图；
/**
*表示此文件节号的片段参数
*碎片。
*/
私有静态最终字符串ARG\u SECTION\u NUMBER=“SECTION\u NUMBER”；
公共占位符片段（）{
}
/**
*返回给定节的此片段的新实例
*号码。
*/
publicstaticdisplaystudio.placeholderFragmentNewInstance（int sectionNumber）{
DisplayStudio.PlaceholderFragment=新的DisplayStudio.PlaceholderFragment（）；
Bundle args=新Bundle（）；
参数Putin（参数段号，段号）；
fragment.setArguments（args）；
返回片段；
}
回收视图rv；
MyCommentsAdapter适配器；
ArrayList recensioni=新的ArrayList（）；
数据库参考数据库；
@凌驾
创建视图上的公共视图（布局、充气机、视图组容器、，
Bundle savedInstanceState）{
Bundle bl=getArguments（）；
if（getArguments（）.getInt（ARG\u节号）==1）
{
视图根视图=充气机。充气（R.layout.fragment_profilo，container，false）；
Intent Intent=getActivity（）.getIntent（）；
String desc=intent.getStringExtra（“desc”）；
最终字符串名称=intent.getStringExtra（“Nome”）；
TextView测试=（TextView）rootView.findViewById（R.id.nome）；
TextView descr=（TextView）rootView.findviewbyd（R.id.desc）；
TextView键=（TextView）rootView.findViewById（R.id.key）；
test.setText（名称）；
描述设置文本（描述）；
String MyKey=bl.getString（MY_STUDIO_KEY）；
key.setText（MyKey）；
返回rootView；
}
else if（getArguments（）.getInt（ARG\u节号）==2）
{
Intent Intent=getActivity（）.getIntent（）；
最终字符串名称=intent.getStringExtra（“Nome”）；
//初始化FIREBASE
mDatabase=FirebaseDatabase.getInstance（）.getReference（）.child（“Studi”）.child（names.child（“valutazioni”）.child（“recensioni”）；
mDatabase.keepSynced（true）；
/*里卡里卡·塔特·勒奥皮尼奥尼*/
刷新数据（）；
视图根视图=充气机。充气（R.layout.fragment\u opinioni，container，false）；
rv=（RecyclerView）rootView.findviewbyd（R.id.MyRecView2s）；
Recension rc=新Recension（）；
rc.setUsername（“Luca”）；
rc.setCommento（“非男性，da应用程序”）；
rc.设定值（“10”）；
rc.setData（“oggi”）；
//ci vuole il推送原始设置值
mDatabase.child（名称）.setValue（rc）；
rv.setLayoutManager（新的LinearLayoutManager（getActivity（））；
返回rootView；
}
其他的
{
视图根视图=充气机。充气（R.layout.fragment\u映射，容器，false）；
SupportMapFragment mapFragment=SupportMapFragment.newInstance（）；
getChildFragmentManager（）.beginTransaction（）.replace（R.id.map，mapFragment.commit（）；
getMapAsync（这个）；
if（mapFragment==null）{
getChildFragmentManager（）.beginTransaction（）.replace（R.id.map，mapFragment.commit（）；
getMapAsync（这个）；
}
返回rootView；
}
}
私有void getUpdates（DataSnapshot DataSnapshot）{
第i.clear（）款；
对于（DataSnapshot ds:DataSnapshot.getChildren（））{
Recension s=新的Recension（）；
s、 setUsername（ds.getValue（recension.class.getUsername（））；
s、 setCommento（ds.getValue（recension.class.getCommento（））；
s、 setRating（ds.getValue（recension.class.getRating（））；
s、 setData（ds.getValue（recension.class.getData（））；
第i条增补；
}
如果（recensioni.size（）>0）{
adapter=new MyCommentsAdapter（getActivity（），recensioni）；
rv.设置适配器（适配器）；
}否则{
Toast.makeText（getActivity（），“NON-CI SONO ANCORA OPINIONI.”，Toast.LENGTH_LONG.show（）；
}
}
//取回
私有数据（）{
mDatabase.addChildEventListener（新的ChildEventListener（）{
@凌驾
公共void onChildAdded（DataSnapshot DataSnapshot，字符串s）{
获取更新（dataSnapshot）；
}
@凌驾
公共void onChildChanged（DataSnapshot DataSnapshot，字符串s）{
获取更新（dataSnapshot）；
}
@凌驾
ChildRemoved上的公共void（DataSnapshot DataSnapshot）{
}
@凌驾
已移动ChildMoved上的公共void（DataSnapshot DataSnapshot，字符串s）{
}
@凌驾
已取消的公共void（DatabaseError DatabaseError）{
}
});
}
@凌驾
4月1日公开作废（谷歌地图谷歌地图）{
谷歌地图=谷歌地图；
Intent Intent=getActivity（）.getIntent（）；
最终字符串名称=intent.getStringExtra（“Nome”）；
字符串posizione1=intent.getStringExtra（“posizione1”）；
字符串posizione2=intent.getStringExtra（“posizione2”）；
尝试
{
public static class PlaceholderFragment extends Fragment implements OnMapReadyCallback {

    private GoogleMap googleMapa;

    /**
     * The fragment argument representing the section number for this
     * fragment.
     */
    private static final String ARG_SECTION_NUMBER = "section_number";

    public PlaceholderFragment() {
    }

    /**
     * Returns a new instance of this fragment for the given section
     * number.
     */
    public static DisplayStudio.PlaceholderFragment newInstance(int sectionNumber) {
        DisplayStudio.PlaceholderFragment fragment = new DisplayStudio.PlaceholderFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        return fragment;
    }

    RecyclerView rv;
    MyCommentsAdapter adapter;
    ArrayList<Recensione> recensioni = new ArrayList<>();
    DatabaseReference mDatabase;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        Bundle bl = getArguments();
        if (getArguments().getInt(ARG_SECTION_NUMBER)==1)
        {

            View rootView = inflater.inflate(R.layout.fragment_profilo, container, false);

            Intent intent = getActivity().getIntent();

            String desc = intent.getStringExtra("Desc");
            final String names = intent.getStringExtra("Nome");

            TextView test = (TextView) rootView.findViewById(R.id.nome);
            TextView descr = (TextView) rootView.findViewById(R.id.desc);
            TextView key = (TextView) rootView.findViewById(R.id.key);

            test.setText(names);
            descr.setText(desc);

            String MyKey = bl.getString(MY_STUDIO_KEY);
            key.setText(MyKey);

        return rootView;
        }
        else if(getArguments().getInt(ARG_SECTION_NUMBER)==2)
        {


            Intent intent = getActivity().getIntent();
            final String names = intent.getStringExtra("Nome");

            //INITIALIZE FIREBASE
            mDatabase = FirebaseDatabase.getInstance().getReference().child("Studi").child(names).child("valutazioni").child("recensioni");
            mDatabase.keepSynced(true);
            /* Ricarica tutte le opinioni */
            refreshData();
            View rootView = inflater.inflate(R.layout.fragment_opinioni, container, false);
            rv = (RecyclerView) rootView.findViewById(R.id.MyRecView2s);

            Recensione rc = new Recensione();
            rc.setUsername("Luca");
            rc.setCommento("Non male, da app");
            rc.setRating("10");
            rc.setData("oggi");
            //ci vuole il push prima del setvalue
            mDatabase.child(names).setValue(rc);
            rv.setLayoutManager(new LinearLayoutManager(getActivity()));

            return rootView;
        }
        else
        {
            View rootView = inflater.inflate(R.layout.fragment_maps, container, false);
            SupportMapFragment mapFragment = SupportMapFragment.newInstance();
            getChildFragmentManager().beginTransaction().replace(R.id.map , mapFragment).commit();
            mapFragment.getMapAsync(this);


            if (mapFragment == null) {
                getChildFragmentManager().beginTransaction().replace(R.id.map , mapFragment).commit();
                mapFragment.getMapAsync(this);
            }


            return rootView;
        }
    }
    private void getUpdates(DataSnapshot dataSnapshot){

        recensioni.clear();

        for (DataSnapshot ds : dataSnapshot.getChildren()){
            Recensione s=new Recensione();
            s.setUsername(ds.getValue(Recensione.class).getUsername());
            s.setCommento(ds.getValue(Recensione.class).getCommento());
            s.setRating(ds.getValue(Recensione.class).getRating());
            s.setData(ds.getValue(Recensione.class).getData());
            recensioni.add(s);
        }

        if(recensioni.size()>0){
            adapter=new MyCommentsAdapter(getActivity(), recensioni);
            rv.setAdapter(adapter);
        }else {
            Toast.makeText(getActivity(),"NON CI SONO ANCORA OPINIONI.", Toast.LENGTH_LONG).show();

        }
    }
    //RETRIEVE
    private void refreshData(){

        mDatabase.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(DataSnapshot dataSnapshot, String s) {
                getUpdates(dataSnapshot);
            }

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

            @Override
            public void onChildRemoved(DataSnapshot dataSnapshot) {

            }

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

            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });

    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        googleMapa = googleMap;
        Intent intent = getActivity().getIntent();

        final String names = intent.getStringExtra("Nome");

        String posizione1 = intent.getStringExtra("Posizione1");
        String posizione2 = intent.getStringExtra("Posizione2");

        try
        {
            //Toast.makeText(MapsActivity.this,posizione1 + " " + posizione2 , Toast.LENGTH_LONG).show();   //not a double
            Double protein = Double.parseDouble(posizione1);
            Double protein2 = Double.parseDouble(posizione2);
             LatLng sydney = new LatLng(protein,protein2);                                                                           //custom icon in drawable
            googleMap.addMarker(new MarkerOptions().position(sydney).title(names)/*.icon(BitmapDescriptorFactory.fromResource(R.drawable.cast_abc_scrubber_control_off_mtrl_alpha))*/);
            googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(sydney, 12.0f));

        }
        catch(NumberFormatException e)
        {
            //  Toast.makeText(DisplayStudio.this, e.toString() , Toast.LENGTH_LONG).show();   //not a double
        }



    }
}

/**
 * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
 * one of the sections/tabs/pages.
 */
public class SectionsPagerAdapter extends FragmentPagerAdapter {

    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {
        // getItem is called to instantiate the fragment for the given page.
        // Return a PlaceholderFragment (defined as a static inner class below).
        return DisplayStudio.PlaceholderFragment.newInstance(position + 1);
    }

    @Override
    public int getCount() {
        // Show 3 total pages.
        return 3;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0:
                return "PROFILO";
            case 1:
                return "OPINIONI";
            case 2:
                return "MAPS";
        }
        return null;
    }
}}

private void getUpdates(DataSnapshot dataSnapshot){
    recensioni.clear();
    for (DataSnapshot ds : dataSnapshot.getChildren()){
        Recensione s=new Recensione();
        s.setUsername(ds.getValue(String.class));
        s.setCommento(ds.getValue(String.class));
        s.setRating(ds.getValue(String.class));
        s.setData(ds.getValue(String.class));
        recensioni.add(s);
    }

    if(recensioni.size()>0){
        adapter=new MyCommentsAdapter(getActivity(), recensioni);
        rv.setAdapter(adapter);
    }else {
        Toast.makeText(getActivity(),"NON CI SONO ANCORA OPINIONI.", Toast.LENGTH_LONG).show();
    }
}