Why is EditText.getText() returning null?

Question

So while I was making my first project in android studio, I tried making an alert box where I can take inputs from 2 EditTexts and take them as arguments for creating an RecyclerView Element, but it turns out it's returning null (even though IDs of the EditTexts are mentioned correctly)

        fa = findViewById(R.id.add_alarm_fab);
        fa.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view){

                AlertDialog.Builder builder = new AlertDialog.Builder(AdminActivity.this);
                builder.setTitle("Add slots");

                View customLayout = getLayoutInflater().inflate(R.layout.alert_dialog_layout,null);
                builder.setView(customLayout);

                builder.setPositiveButton("Add", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        EditText editText1 = findViewById(R.id.edCentre);
                        EditText editText2 = findViewById(R.id.edSlots);

                        String centreName = editText1.getText().toString();

                        Integer slots = Integer.parseInt(editText2.getText().toString());
                        if (centreName!=null && slots!=null)
                            medCentreArrayList.add(new MedCentre(centreName,slots));
                        ad.notifyDataSetChanged();
                    }
                });
                builder.create().show();
            }
        });

This is my XML file for the alert dialog:-

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <EditText
        android:id="@+id/edSlots"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:ems="10"
        android:hint="Slots available"
        android:inputType="textPersonName"
        android:padding="20dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <EditText
        android:id="@+id/edCentre"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:padding="20dp"
        android:ems="10"
        android:hint="Centre Name"
        android:inputType="textPersonName"
        app:layout_constraintBottom_toTopOf="@+id/edSlots"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

Image of alert dialog layout:

And Image of alert dialog:

Answer 1

Looks like you need to find your view in the dialog container, something like this:

EditText editText1 = customLayout.findViewById(R.id.edCentre);