java_mot_testing/app/src/main/res/layout/ex9_data_binding.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <data>
        <variable
            name="calc"
            type="io.n0x.android.java_mot_testing.FractionCalculator" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <Button
            android:id="@+id/button_add"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="+"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <Button
            android:id="@+id/button_sub"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="-"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/button_add" />

        <Button
            android:id="@+id/button_mult"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="*"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/button_sub" />

        <Button
            android:id="@+id/button_div"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="/"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.501"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/button_mult" />

        <TextView
            android:id="@+id/txt_equals"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="48dp"
            android:text="="
            android:textSize="34sp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.183"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/button_div" />

        <TextView
            android:text="@{calc.denomResult}"
            android:id="@+id/txt_denom_result"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="3dp"
            android:layout_marginBottom="412dp"
            android:textAlignment="center"
            android:textSize="34sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.247"
            app:layout_constraintStart_toEndOf="@+id/txt_equals"
            app:layout_constraintTop_toBottomOf="@+id/txt_enum_result" />

        <TextView
            android:text="Test1234"
            android:id="@+id/txt_enum_result"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="32dp"
            android:textAlignment="center"
            android:textSize="34sp"
            app:layout_constraintBottom_toTopOf="@+id/txt_denom_result"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.247"
            app:layout_constraintStart_toEndOf="@+id/txt_equals"
            app:layout_constraintTop_toBottomOf="@+id/button_div" />

        <EditText
            android:text="@{calc.enumRight}"
            android:id="@+id/enumRight"
            android:layout_width="140dp"
            android:layout_height="50dp"
            android:layout_marginTop="32dp"
            android:ems="10"
            android:hint="Zähler"
            android:inputType="numberSigned"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toEndOf="@+id/button_add"
            app:layout_constraintTop_toTopOf="parent" />

        <EditText
            android:text="@{calc.enumLeft}"
            android:id="@+id/enumLeft"
            android:layout_width="140dp"
            android:layout_height="50dp"
            android:layout_marginTop="32dp"
            android:ems="10"
            android:hint="Zähler"
            android:inputType="numberSigned"
            app:layout_constraintEnd_toStartOf="@+id/button_add"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <EditText
            android:text="@{calc.denomLeft}"
            android:id="@+id/denomLeft"
            android:layout_width="140dp"
            android:layout_height="50dp"
            android:layout_marginTop="32dp"
            android:ems="10"
            android:hint="Nenner"
            android:inputType="number"
            app:layout_constraintEnd_toStartOf="@+id/button_mult"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/enumLeft" />

        <EditText
            android:text="@{calc.denomRight}"
            android:id="@+id/denomRight"
            android:layout_width="140dp"
            android:layout_height="50dp"
            android:layout_marginTop="32dp"
            android:ems="10"
            android:hint="Nenner"
            android:inputType="number"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toEndOf="@+id/button_mult"
            app:layout_constraintTop_toBottomOf="@+id/enumRight" />

    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>