when data is changed in real time database(firebase) app crashes

Question

it don't just do with this data , error is same with when i save data from other device into databse (firebase) app crashes where data is retrieved and set into recycle view in other device

onDataChange is realtime when data is changed it is automatically called
Notification Class



public class Notifications {
    private String Name;
    private String Email;
    private String Message;
    private String Time;
    private String Date;

    public Notifications() {

    }

    public Notifications(String Name, String Email, String Message, String Time, String Date) {
        this.Name = Name;
        this.Email = Email;
        this.Message = Message;
        this.Time = Time;
        this.Date = Date;
    }

    public String getName() {
        return Name;
    }

    public String getEmail() {
        return Email;
    }

    public String getMessage() {
        return Message;
    }

    public String getTime() {
        return Time;
    }

    public String getDate() {
        return Date;
    }
}

DatabaseReference userref = FirebaseDatabase.getInstance().getReference().child("Notification");
        userref.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                if (dataSnapshot.exists()) {
                    notificationList.clear();
                    for (DataSnapshot userSnapshot : dataSnapshot.getChildren()) {

                        Notifications notifications = userSnapshot.getValue(Notifications.class);

                        notificationList.add(notifications);

                    }
                    Collections.reverse(notificationList);
                    mAdapter = new Adapter_Notification(notificationList);
                    mRecyclerView.addItemDecoration(new DividerItemDecoration(getContext(), LinearLayoutManager.VERTICAL));

                    mRecyclerView.setAdapter(mAdapter);


                }

            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });

this error is shown

com.google.firebase.database.DatabaseException: Can't convert object of type java.lang.Boolean to type com.example.simpleapplocker.Notifications

at the line

 notificationList.add(notifications);

after start is retrieves that data and shows in recycle view it mean data exists or maybe notification is created but other data is not uploaded and this function is called maybe??

sir first check your notification model class attributes data types. and check your datachange respone . is it give you the object or boolean result. — Hasnain Sabir, Sep 13 '19 at 07:02
According to your request from [here](https://stackoverflow.com/questions/57883129/how-can-i-point-to-the-random-key-firebase-user-id/57885392#comment102253424_57885392), I will ask you now to add add your database structure as a JSON file or at least as a screenshot. Please also responde with @AlexMamo — Alex Mamo, Sep 13 '19 at 08:45
@AlexMamo thanks for being here i just added image here actually it works fine when there is change in any notification children but it crashes when new children is added there is also a function setOnAddChildren but then it don't retrieves all notifications — Muhammad Owais Chaudhary, Sep 13 '19 at 14:29
@HasnainSabir i just updated question with image you can have a look there is not boolean value — Muhammad Owais Chaudhary, Sep 13 '19 at 14:30
@MuhammadOwaisChaudhary Please also add the content of your `Notifications` class. — Alex Mamo, Sep 13 '19 at 14:32

score 1 · Answer 1 · answered Sep 02 '20 at 19:32

Try this method, it worked for me

FirebaseDatabase database = FirebaseDatabase.getInstance();
                DatabaseReference myRef = database.getReference("Notification");
                myRef.addChildEventListener(new ChildEventListener() {
                    @Override
                    public void onChildAdded(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
                        if(dataSnapshot.exist()) {
        Notifications notifications = userSnapshot.getValue(Notifications.class);
        
                                notificationList.add(notifications);
        
                            }
                            Collections.reverse(notificationList);
                            mAdapter = new 
      Adapter_Notification(notificationList);
                            mRecyclerView.addItemDecoration(new DividerItemDecoration(getContext(), LinearLayoutManager.VERTICAL));
        
                            mRecyclerView.setAdapter(mAdapter);
     
                    }
        
                    @Override
                    public void onChildChanged(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
        
                    }
        
                    @Override
                    public void onChildRemoved(@NonNull DataSnapshot dataSnapshot) {
        
                    }
        
                    @Override
                    public void onChildMoved(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
        
                    }
        
                    @Override
                    public void onCancelled(@NonNull DatabaseError databaseError) {
        
                    }
                });

Muntasir Aonik · Answer 2 · 2019-09-12T19:02:15.600

0

Notifications notifications = userSnapshot.getValue(Notifications.class);

In this line, you are getting the error that says Boolean object can't be converted to Notifications. This may appear if you have set the value of that child to true or false (Without double quotes). See it again and try to add a double quote around the "true" or "false" that you want to set to the child value.

edited Sep 12 '19 at 19:02

answered Sep 12 '19 at 18:18

Muntasir Aonik

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then how it will get data of all notifications that exists – Muhammad Owais Chaudhary Sep 12 '19 at 18:23
try this method and let me know if it works. this method will only call when app starts. – Muntasir Aonik Sep 12 '19 at 18:27
Please add your database structure and please also response – Muntasir Aonik Sep 12 '19 at 18:52
i just added image you can check – Muhammad Owais Chaudhary Sep 13 '19 at 14:30
Use Firebase Recycleradapter. @MuhammadOwaisChaudhary – Muntasir Aonik Sep 22 '19 at 07:40

when data is changed in real time database(firebase) app crashes

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