Why does my Android app crash after clicking the send message button?

Question

For some reason, when I click on the send message button, the chat that I do using the video tutorial crashes. I don’t see any error codes. Could you tell me the reason? Thanks in advance. I tried the suggested options, but the application crashes anyway.

public class MainActivity extends AppCompatActivity {

private static int SIGN_IN_CODE=1;
private RelativeLayout activity_main;
private FirebaseListAdapter<Message> adapter;
private FloatingActionButton sendBtn;

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(requestCode==SIGN_IN_CODE) {
           if(requestCode == RESULT_OK) {
               Snackbar.make(activity_main, "You are authorized", Snackbar.LENGTH_LONG).show();
               displayAllMessages();
               } else {
                 Snackbar.make(activity_main, "You are not authorizedы", Snackbar.LENGTH_LONG).show();
                 finish();
           }
        }
    }

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

        activity_main=findViewById(R.id.activity_main);
        sendBtn = findViewById(R.id.btnSend);
        sendBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                EditText textField = findViewById(R.id.messageField);
                if(textField.getText().toString()=="")
                    return;
                FirebaseDatabase.getInstance().getReference().push().setValue(new Message(FirebaseAuth.getInstance().getCurrentUser().getEmail(), textField.getText().toString()));
                textField.setText("");
            }
        });

        //Пользователь ещё не авторизован
        if (FirebaseAuth.getInstance().getCurrentUser()==null)
            startActivityForResult(AuthUI.getInstance().createSignInIntentBuilder().build(), SIGN_IN_CODE);
        //Пользователь авторизован
        else {
            Snackbar.make(activity_main, "You are authorized", Snackbar.LENGTH_LONG).show();
            displayAllMessages();
        }
    }

    private void displayAllMessages() {
        ListView listOfMessages = findViewById(R.id.list_of_messages);
        FirebaseListOptions<Message> options =
                new FirebaseListOptions.Builder<Message>()
                        .setQuery(FirebaseDatabase.getInstance().getReference(), Message.class)
                        .setLayout(R.layout.list_item)
                        .build();
        adapter = new FirebaseListAdapter<Message>(options){
            @Override
            protected void populateView(View v, Message model, int position) {
                TextView mess_user, mess_time, mess_text;
                mess_user = v.findViewById(R.id.message_user);
                mess_time = v.findViewById(R.id.message_time);
                mess_text = v.findViewById(R.id.message_text);

                mess_user.setText(model.getUserName());
                mess_text.setText(model.getTextMessage());
                mess_time.setText(DateFormat.format("dd-MM-yyyy HH:mm:ss", model.getMessageTime()));
            }
        };
        listOfMessages.setAdapter(adapter);
    }
}

import

My app

"Karasik" crashed again

Answer 1

change the condition

textField.getText().toString()==""

to be :

textField.getText().toString().equals("");

Like this :

sendBtn.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    EditText textField = findViewById(R.id.messageField);
                    if(!textField.getText().toString().equals("")){
                  FirebaseDatabase.getInstance().getReference().push().setValue(new Message(FirebaseAuth.getInstance().getCurrentUser().getEmail(), textField.getText().toString()));
                    textField.setText("");
                 }
                }
            });

Answer 2

Try replacing:

if(textField.getText().toString()=="") return;

With:

if(textField.getText().toString().equals("")) return;