Why does My app stops after i press the button

Question

this is how i have registered the users..but it is not sending anything to database though the registration completes just fine

private void registerUser(){



        //getting email and password from edit texts
        String email = editTextEmail.getText().toString().trim();
        String password  = editTextPassword.getText().toString().trim();

        //checking if email and passwords are empty
        if(TextUtils.isEmpty(email)){
            Toast.makeText(this,"Please enter email",Toast.LENGTH_LONG).show();
            return;
        }

        if(TextUtils.isEmpty(password)){
            Toast.makeText(this,"Please enter password",Toast.LENGTH_LONG).show();
            return;
        }

        //if the email and password are not empty
        //displaying a progress dialog

        progressDialog.setMessage("Registering Please Wait...");
        progressDialog.show();


        //creating a new user
        firebaseAuth.createUserWithEmailAndPassword(email, password)
                .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        //checking if success
                        if(task.isSuccessful()){
                            finish();
                            startActivity(new Intent(getApplicationContext(), ProfileActivity.class));
                        }else{
                            //display some message here
                            Toast.makeText(MainActivity.this,"Registration Error",Toast.LENGTH_LONG).show();
                        }
                        progressDialog.dismiss();
                    }
                });

    }

then here is my login.activity. i can log in just fine but i wonder what cretiria is this code using to log in users??

private void userLogin(){
    String email = editTextEmail.getText().toString().trim();
    String password  = editTextPassword.getText().toString().trim();


    //checking if email and passwords are empty
    if(TextUtils.isEmpty(email)){
        Toast.makeText(this,"Please enter email",Toast.LENGTH_LONG).show();
        return;
    }

    if(TextUtils.isEmpty(password)){
        Toast.makeText(this,"Please enter password",Toast.LENGTH_LONG).show();
        return;
    }

    //if the email and password are not empty
    //displaying a progress dialog

    progressDialog.setMessage("Registering Please Wait...");
    progressDialog.show();

    //logging in the user
    firebaseAuth.signInWithEmailAndPassword(email, password)
            .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(@NonNull Task<AuthResult> task) {
                    progressDialog.dismiss();
                    //if the task is successfull
                    if(task.isSuccessful()){
                        //start the profile activity
                        finish();
                        startActivity(new Intent(getApplicationContext(), ProfileActivity.class));
                    }
                }
            });

}

Answer 1

The problem is described here:

com.fasterxml.jackson.databind.JsonMappingException: Can not instantiate value of type [simple type, class com.example.moses.bstation.Person] from String value; no single-String constructor/factory method

It seems that the mapping between the JSON response and the Person class is incorrect.

Double check your Person class implementation, also please share your Person class implementation and a sample from the JSON response.

Answer 2

change your person class like this

    public class Person {

    private String Username;
    private String Email;

    public Person(String email,String userName) {
     this.Username=userName;
     this.Email=email;

      /*Blank default constructor essential for Firebase*/
    }
    //Getters and setters
    public String getUsername() {
        return Username;
    }

    public void setUsername(String Username) {
        this.Username = Username;
    }

    public String getEmail() {
        return Email;
    }

    public void setEmail(String Email) {
        this.Email = Email;
    }
}

then use it like this

 Person person=new Person();
 person.setUsername(Username);
 person.setEmail(Email);
 Firebase newRef = ref.child("Users").push();
 newRef.setValue(person);

then use this to get values

 newRef.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(DataSnapshot dataSnapshot, String s) {
               Person person = dataSnapshot.getValue(Person.class);
 String string = "Username: "+person.getName()+"\nEmail: "+person.getEmail()+"\n\n";

            }

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

            }

            @Override
            public void onChildRemoved(DataSnapshot dataSnapshot) {

            }

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

            }

            @Override
            public void onCancelled(FirebaseError firebaseError) {

            }
        });