AlertDialog.java

LayoutInflater factory = LayoutInflater.from(this); // this это context
// final - для того чтобы использовать его в OnClickListener()
final View alertView = factory.inflate(R.layout.layout_add_note, null);

AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setView(alertView);
builder.setTitle(R.string.alert_title_add);
builder.setNegativeButton(R.string.alert_cancel, null);
builder.setPositiveButton(R.string.menu_add, new DialogInterface.OnClickListener() {
    @Override
    public void onClick(DialogInterface dialog, int id) {
        EditText editTextNote = (EditText) alertView.findViewById(R.id.editTextNote);
        EditText editTextNoteTitle = (EditText) alertView.findViewById(R.id.editTextNoteTitle);
      
        addNote(editTextNoteTitle.getText().toString() ,editTextNote.getText().toString());
      
        dataUpdated();
    }
});
builder.show();

// layout_add_note
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">

    <EditText
        android:id="@+id/editTextNoteTitle"
        android:inputType="textEmailAddress"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:layout_marginLeft="4dp"
        android:layout_marginRight="4dp"
        android:layout_marginBottom="4dp"
        android:hint="@string/title" />

    <EditText
        android:id="@+id/editTextNote"
        android:inputType="text|textMultiLine"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:layout_marginLeft="4dp"
        android:layout_marginRight="4dp"
        android:layout_marginBottom="4dp"
        android:hint="@string/note" />

</LinearLayout>