fragment_game.xml

<?xml version="1.0" encoding="utf-8"?><!--
  ~ Copyright 2018, The Android Open Source Project
  ~
  ~ Licensed under the Apache License, Version 2.0 (the "License");
  ~ you may not use this file except in compliance with the License.
  ~ You may obtain a copy of the License at
  ~
  ~     http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing, software
  ~ distributed under the License is distributed on an "AS IS" BASIS,
  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ~ See the License for the specific language governing permissions and
  ~ limitations under the License.
  -->

<layout 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"
    tools:context="com.example.android.navigation.GameFragment">

    <data>

        <variable
            name="game"
            type="com.example.android.navigation.GameFragment" />
    </data>

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fillViewport="true">

        <androidx.constraintlayout.widget.ConstraintLayout
            android:id="@+id/frameLayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <ImageView
                android:id="@+id/questionImage"
                android:layout_width="0dp"
                android:layout_height="@dimen/image_header_height"
                android:layout_marginStart="@dimen/horizontal_margin"
                android:layout_marginTop="@dimen/vertical_margin"
                android:layout_marginEnd="@dimen/horizontal_margin"
                android:layout_marginBottom="@dimen/vertical_margin"
                android:scaleType="fitCenter"
                app:layout_constraintBottom_toTopOf="@+id/questionText"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent"
                app:layout_constraintVertical_chainStyle="packed"
                app:srcCompat="@drawable/android_category_simple" />

            <TextView
                android:id="@+id/questionText"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_marginStart="@dimen/question_horizontal_margin"
                android:layout_marginTop="@dimen/vertical_margin"
                android:layout_marginEnd="@dimen/question_horizontal_margin"
                android:layout_marginBottom="@dimen/vertical_margin"
                android:fontFamily="sans-serif"
                android:text="@{game.currentQuestion.text}"
                android:textSize="@dimen/question_text_size"
                android:textStyle="bold"
                android:typeface="normal"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/questionImage"
                tools:text="What color is the Android mascot?" />

            <RadioGroup
                android:id="@+id/questionRadioGroup"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_marginStart="@dimen/question_horizontal_margin"
                android:layout_marginTop="@dimen/vertical_margin"
                android:layout_marginEnd="@dimen/question_horizontal_margin"
                android:animateLayoutChanges="true"
                android:orientation="vertical"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/questionText">

                <RadioButton
                    android:id="@+id/firstAnswerRadioButton"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginBottom="@dimen/question_vertical_margin"
                    android:checked="true"
                    android:text="@{game.answers[0]}"
                    android:textSize="@dimen/answer_text_size"
                    tools:text="Blue" />

                <RadioButton
                    android:id="@+id/secondAnswerRadioButton"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginBottom="@dimen/question_vertical_margin"
                    android:text="@{game.answers[1]}"
                    android:textSize="@dimen/answer_text_size"
                    tools:text="Green" />

                <RadioButton
                    android:id="@+id/thirdAnswerRadioButton"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginBottom="@dimen/question_vertical_margin"
                    android:text="@{game.answers[2]}"
                    android:textSize="@dimen/answer_text_size"
                    tools:text="Yellow" />

                <RadioButton
                    android:id="@+id/fourthAnswerRadioButton"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="@{game.answers[3]}"
                    android:textSize="@dimen/answer_text_size"
                    tools:text="Red" />
            </RadioGroup>

            <Button
                android:id="@+id/submitButton"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginStart="@dimen/question_horizontal_margin"
                android:layout_marginTop="@dimen/vertical_margin"
                android:layout_marginEnd="@dimen/question_horizontal_margin"
                android:text="@string/submit_button"
                android:textSize="@dimen/button_text_size"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/questionRadioGroup" />
        </androidx.constraintlayout.widget.ConstraintLayout>
    </ScrollView>
</layout>