Custom Adapter ListView Error

Question

I am trying to list some user detail in a Listview , in each row show 4 String.

The String is got from Firebase .

I always get some error. Any idea about the reason of the error or any other solution?

This is my code:

MainActivity

public class SearchActivity extends AppCompatActivity {

    private ListView mListView;
    //public ArrayList<String> mUser = new ArrayList<>();
    private String userID;
    private String Lat;
    private String Lng;
    private Button mRefresh;
    private String Name;
    private String Birthday;
    private String Gender;
    private String Email;

    private FirebaseAuth mAuth = FirebaseAuth.getInstance();
    private FirebaseDatabase firebaseDatabase = FirebaseDatabase.getInstance();
    private DatabaseReference DatabaseReference = firebaseDatabase.getReference();

    //private DatabaseReference DatabaseReference = firebaseDatabase.getReference().child("Users/");
    //private DatabaseReference CoordenateReference = firebaseDatabase.getReference().child("Coordenate/");

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_search);


        mListView = findViewById(R.id.listViewSearch);

        FirebaseUser user = mAuth.getCurrentUser();
        userID = user.getUid();
        mRefresh = findViewById(R.id.buttonRefresh);


        mRefresh.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                DatabaseReference.addValueEventListener(new ValueEventListener() {
                    @Override
                    public void onDataChange(DataSnapshot dataSnapshot) {
                        listClean();
                        FirebaseUser user = mAuth.getCurrentUser();
                        userID = user.getUid();
                        Lat = dataSnapshot.child("Users").child(userID).child("Coordenates/Rute/Lat").getValue(String.class);
                        Lng = dataSnapshot.child("Users").child(userID).child("Coordenates/Rute/Lng").getValue(String.class);
                        DataSnapshot dS = dataSnapshot.child("Coordenate").child(Lat).child(Lng);

                        for(DataSnapshot Ds : dS.getChildren()) {
                            Object key = Ds.getKey();
                            String StringKey = String.valueOf(key);
                            getname(StringKey);
                            //mUser.add(getName(StringKey));
                            //mUser.add(Name);
                        }

                    }

                    @Override
                    public void onCancelled(DatabaseError databaseError) {
                        Toast.makeText(SearchActivity.this,"Error 404",Toast.LENGTH_SHORT).show();

                    }
                });
            }
        });



    }
    private void getname(String ID){


        final String IDfinal = ID;
        Toast.makeText(SearchActivity.this,ID,Toast.LENGTH_SHORT).show();
        DatabaseReference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                Name = dataSnapshot.child("Users").child(IDfinal).child("name").getValue(String.class);
                Email = dataSnapshot.child("Users").child(IDfinal).child("email").getValue(String.class);
                Gender = dataSnapshot.child("Users").child(IDfinal).child("gender").getValue(String.class);
                Birthday = dataSnapshot.child("Users").child(IDfinal).child("data_birth").getValue(String.class);

                list();


                Toast.makeText(SearchActivity.this,Name,Toast.LENGTH_SHORT).show();

            }

            @Override
            public void onCancelled(DatabaseError databaseError) {
                Toast.makeText(SearchActivity.this,"Error 404",Toast.LENGTH_SHORT).show();

            }
        });
    }

    private void list(){
        //final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, mUser);
        //mListView.setAdapter(new customAdapter(this,new String[]{Name}));
        //mUser.add(Name);
        //arrayAdapter.notifyDataSetChanged();
        setContentView(R.layout.activity_search);
        List<UserInformation> userInformationsList = new ArrayList<>();
        UserInformation userInformation = new UserInformation(Name,Email,Gender,Birthday);
        userInformationsList.add(userInformation);
        customAdapter customAdapterIntent= new customAdapter((ValueEventListener) this,R.layout.userslist,userInformationsList);
        mListView.setAdapter(customAdapterIntent);
    }
}

This is userslist.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical">

    <TextView
        android:id="@+id/textNameList"
        android:textSize="25dp"
        android:textAlignment="textStart"
        android:text="Name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="start"
        android:layout_margin="10dp"/>

    <TextView
        android:id="@+id/textEmailList"
        android:textSize="15dp"
        android:textAlignment="textStart"
        android:text="Age"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="start"
        android:layout_margin="10dp"/>

    <TextView
        android:id="@+id/textBirthdayList"
        android:textSize="15dp"
        android:textAlignment="textStart"
        android:text="Birthday"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="start"
        android:layout_margin="10dp"/>

    <TextView
        android:id="@+id/textGenderList"
        android:textSize="15dp"
        android:textAlignment="textStart"
        android:text="gender"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="start"
        android:layout_margin="10dp"/>

This is Userinformation.java

public class UserInformation {


    private static String Name;
    private static String Gender;
    private static String Email;
    private static String Birthday;

    public UserInformation(String Name,String Gender,String Email,String Birthday){
        this.Birthday=Birthday;
        this.Email=Email;
        this.Gender=Gender;
        this.Name=Name;
    }

    public static String getName(){return Name;}
    public static String getEmail(){return Email;}
    public static String getGender(){return Gender;}
    public static String getBirthday(){return Birthday;}

}

This is the adapter

public class customAdapter extends ArrayAdapter<UserInformation> {




    public customAdapter(ValueEventListener context, int layoutResource, 
    List<UserInformation> userInformationsList) {
        super((Context) context, layoutResource, userInformationsList);

    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        View view = convertView;

        if (view == null) {
            LayoutInflater layoutInflater = LayoutInflater.from(getContext());
            view = layoutInflater.inflate(R.layout.userslist, null);
        }

        UserInformation userInformation = getItem(position);

        if (userInformation != null) {
            TextView Name = (TextView) view.findViewById(R.id.textNameList);
            //name.setText(name[position]);
            TextView email = (TextView) view.findViewById(R.id.textEmailList);
            //email.setText(Email[position]);
            TextView gender = (TextView) view.findViewById(R.id.textGenderList);
            //gender.setText(Gender[position]);
            TextView birthday = (TextView) view.findViewById(R.id.textBirthdayList);
            //birthday.setText(Birthday[position]);

            if (Name != null) {
                Name.setText(UserInformation.getName());
            }
            if (email != null) {
                email.setText(UserInformation.getEmail());
            }
            if (gender != null) {
                gender.setText(UserInformation.getGender());
            }
            if (birthday != null) {
                birthday.setText(UserInformation.getBirthday());
            }
        }

        return view;
    }
}

This is the error

E/AndroidRuntime: FATAL EXCEPTION: main
              Process: com.example.enrik.afrodita, PID: 2629
              java.lang.ClassCastException: 
com.example.enrik.afrodita.SearchActivity cannot be cast to 
com.google.firebase.database.ValueEventListener
                  at 
com.example.enrik.afrodita.SearchActivity.list(SearchActivity.java:130)
                  at 

com.example.enrik.afodita.SearchActivity.access$1100(SearchActivity.java:24)
                  at 

com.example.enrik.adita.Searchivity$2.onDataChange(SearchActivity.java:106)
                  at com.google.android.gms.internal.zzdtn.zza(Unknown Source)
                  at com.google.android.gms.internal.zzdvi.zzbur(Unknown Source)
                  at com.google.android.gms.internal.zzdvo.run(Unknown Source)
                  at android.os.Handler.handleCallback(Handler.java:751)
                  at android.os.Handler.dispatchMessage(Handler.java:95)
                  at android.os.Looper.loop(Looper.java:154)
                  at android.app.ActivityThread.main(ActivityThread.java:6119)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

Answer 1

You need to pass Context not ValueEventListener so change adapter as

public customAdapter(/*ValueEventListener*/ Context context, int layoutResource, 
List<UserInformation> userInformationsList) {
    super(context, layoutResource, userInformationsList);

}

and remove the cast as well

 customAdapter customAdapterIntent= new customAdapter(/*(ValueEventListener)*/ this,R.layout.userslist,userInformationsList);

where context is required by the layoutinflater or adapter to access the resources when you call getContext()

and also remove setContentView(R.layout.activity_search); from list method, you are doing it twice , so no need

---

Thank so much, I did as you said and It works but it only list the last user's information

You need to fetch all the users and add them in list because currently you are storing information of last user in as string values and using those values to create list of single user object.

// outside onCreate
List<UserInformation> users = new ArrayList<>();


mRefresh.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {

        DatabaseReference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                listClean();
                FirebaseUser user = mAuth.getCurrentUser();
                userID = user.getUid();
                Lat = dataSnapshot.child("Users").child(userID).child("Coordenates/Rute/Lat").getValue(String.class);
                Lng = dataSnapshot.child("Users").child(userID).child("Coordenates/Rute/Lng").getValue(String.class);
                DataSnapshot dS = dataSnapshot.child("Coordenate").child(Lat).child(Lng);

                for(DataSnapshot Ds : dS.getChildren()) {
                    Object key = Ds.getKey();
                    String StringKey = String.valueOf(key);

                    // fetch the user Object based on key and add it to list
                    users.add(lidataSnapshot.child("Users").child(StringKey).getValue(UserInformation.class));
                }
                 // now display list with all user information 
                 customAdapter customAdapterIntent= new customAdapter(SearchActivity.this,
                                                                      R.layout.userslist,
                                                                      users);
                 mListView.setAdapter(customAdapterIntent);

            }

            @Override
            public void onCancelled(DatabaseError databaseError) {
                Toast.makeText(SearchActivity.this,"Error 404",Toast.LENGTH_SHORT).show();

            }
        });
    }
});