Code Block Sample

This is how the code should look like:

Kotlin:

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import com.google.firebase.database.DatabaseReference
import com.google.firebase.database.FirebaseDatabase
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)


        // Database reference pointing to root of database
        val rootRef: DatabaseReference = FirebaseDatabase.getInstance().reference

        // Database reference pointing to demo node
        val demoRef: DatabaseReference = rootRef.child("demo")

        btnSubmit.setOnClickListener {
            val value: String = etValue.text.toString()

            // Push creates a unique id in database
            demoRef.setValue(value)
        }
    }
}

Java:

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;

public class MainActivity extends AppCompatActivity {

    EditText editText;
    Button submit;
    DatabaseReference rootRef, demoRef;

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

        editText = findViewById(R.id.etValue);
        submit = findViewById(R.id.btnSubmit);

        // Database reference pointing to root of database
        rootRef = FirebaseDatabase.getInstance().getReference();

        // Database reference pointing to demo node
        demoRef = rootRef.child("demo");

        submit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String value = editText.getText().toString();

                // Push creates a unique id in database
                demoRef.setValue(value);
            }
        });
    }
}

This is what it currently looks like when inserted inside the UB tabs block:

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import com.google.firebase.database.DatabaseReference
import com.google.firebase.database.FirebaseDatabase
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)


        // Database reference pointing to root of database
        val rootRef: DatabaseReference = FirebaseDatabase.getInstance().reference

        // Database reference pointing to demo node
        val demoRef: DatabaseReference = rootRef.child("demo")

        btnSubmit.setOnClickListener {
            val value: String = etValue.text.toString()

            // Push creates a unique id in database
            demoRef.setValue(value)
        }
    }
}

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;

public class MainActivity extends AppCompatActivity {

    EditText editText;
    Button submit;
    DatabaseReference rootRef, demoRef;

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

        editText = findViewById(R.id.etValue);
        submit = findViewById(R.id.btnSubmit);

        // Database reference pointing to root of database
        rootRef = FirebaseDatabase.getInstance().getReference();

        // Database reference pointing to demo node
        demoRef = rootRef.child("demo");

        submit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String value = editText.getText().toString();

                // Push creates a unique id in database
                demoRef.setValue(value);
            }
        });
    }
}

It was working perfectly fine earlier. I am not sure what issue came up with the recent update.