四则运算

设计思路：

UI设计思路：

一共四个页面：首页，习题页，成功页，失败页

将这四个页面通过Navigation连接起来形成一条逻辑关系。

 接下来就是对每个页面进行设计。

首页：一个TextView和一个ImageView还有一个Button，顶部是一个最高分Textview，通过button来进入出题页面

<?xml version="1.0" encoding="utf-8"?>
<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">

    <data>
        <variable
            name="data"
            type="com.example.calculation.MyViewModel" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".TitleFragment">

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            app:layout_constraintGuide_percent="0.1" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            app:layout_constraintGuide_percent="0.9" />

        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/CalName"
            android:textSize="@dimen/huge_size"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toStartOf="@+id/guideline2"
            app:layout_constraintStart_toStartOf="@+id/guideline"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.106" />

        <ImageView
            android:id="@+id/imageView"
            android:layout_width="320dp"
            android:layout_height="349dp"
            android:contentDescription="@string/title_image"
            android:src="@drawable/size"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintDimensionRatio="w,1:1"
            app:layout_constraintEnd_toStartOf="@+id/guideline2"
            app:layout_constraintHorizontal_bias="0.56"
            app:layout_constraintStart_toStartOf="@+id/guideline"
            app:layout_constraintTop_toTopOf="parent" />

        <Button
            android:id="@+id/button"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="@string/title_button"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toStartOf="@+id/guideline2"
            app:layout_constraintHorizontal_bias="0.0"
            app:layout_constraintStart_toStartOf="@+id/guideline"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.862" />

        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{@string/higer_score(data.highScore)}"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.883"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.036"
            tools:text="High Score:%d" />
    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

　　出题页面：顶部代表目前的得分情况，中间是一个算式，下面是答案，接下来是4行3列，12个按钮代表你的操作。

<?xml version="1.0" encoding="utf-8"?>
<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">

    <data>
        <variable
            name="data"
            type="com.example.calculation.MyViewModel" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".QuestionFragment">

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.1" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.2" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline5"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.33" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline6"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.4" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline10"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.5" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline11"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.6" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline12"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.7" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline7"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.8" />

        <TextView
            android:id="@+id/textView3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{@string/Current_Score(data.currentScore)}"
            app:layout_constraintBottom_toTopOf="@+id/guideline3"
            app:layout_constraintEnd_toStartOf="@+id/guideline9"
            app:layout_constraintHorizontal_bias="0.537"
            app:layout_constraintStart_toStartOf="@+id/guideline8"
            app:layout_constraintTop_toTopOf="@+id/guideline3"
            app:layout_constraintVertical_bias="0.473"
            tools:text="Score:0" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline8"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            app:layout_constraintGuide_percent="0.1" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline9"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            app:layout_constraintGuide_percent="0.9" />

        <TextView
            android:id="@+id/textView4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="@dimen/huge_size"
            android:text="@{String.valueOf(data.leftNumber)}"
            app:layout_constraintBottom_toBottomOf="@+id/textView5"
            app:layout_constraintEnd_toStartOf="@+id/textView5"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="@+id/guideline8"
            app:layout_constraintTop_toTopOf="@+id/textView5"
            tools:text="1" />

        <TextView
            android:id="@+id/textView5"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="@dimen/huge_size"
            android:text="@{String.valueOf(data.operator)}"
            app:layout_constraintBottom_toBottomOf="@+id/textView6"
            app:layout_constraintEnd_toStartOf="@+id/textView6"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toEndOf="@+id/textView4"
            app:layout_constraintTop_toTopOf="@+id/textView6"
            tools:text="+" />

        <TextView
            android:id="@+id/textView6"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="@dimen/huge_size"
            android:text="@{String.valueOf(data.rigthNumber)}"
            app:layout_constraintBottom_toBottomOf="@+id/textView7"
            app:layout_constraintEnd_toStartOf="@+id/textView7"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toEndOf="@+id/textView5"
            app:layout_constraintTop_toTopOf="@+id/textView7"
            tools:text="2" />

        <TextView
            android:id="@+id/textView7"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="="
            android:textSize="@dimen/huge_size"
            app:layout_constraintBottom_toBottomOf="@+id/textView8"
            app:layout_constraintEnd_toStartOf="@+id/textView8"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toEndOf="@+id/textView6"
            app:layout_constraintTop_toTopOf="@+id/textView8"
            tools:text="=" />

        <TextView
            android:id="@+id/textView8"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/Cal_Answer"
            android:textSize="@dimen/huge_size"
            app:layout_constraintBottom_toTopOf="@+id/guideline4"
            app:layout_constraintEnd_toStartOf="@+id/guideline9"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toEndOf="@+id/textView7"
            app:layout_constraintTop_toTopOf="@+id/guideline4" />

        <TextView
            android:id="@+id/textView9"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Your Answer:"
            android:textSize="@dimen/mid_size"
            app:layout_constraintBottom_toTopOf="@+id/guideline5"
            app:layout_constraintEnd_toStartOf="@+id/guideline9"
            app:layout_constraintStart_toStartOf="@+id/guideline8"
            app:layout_constraintTop_toTopOf="@+id/guideline5" />

        <Button
            android:id="@+id/button1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="1"
            android:textSize="@dimen/button_size"
            app:layout_constraintBottom_toTopOf="@+id/guideline10"
            app:layout_constraintEnd_toStartOf="@+id/button2"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="@+id/guideline8"
            app:layout_constraintTop_toTopOf="@+id/guideline6" />

        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="2"
            android:textSize="@dimen/button_size"
            app:layout_constraintBottom_toBottomOf="@+id/button1"
            app:layout_constraintEnd_toStartOf="@+id/button3"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toEndOf="@+id/button1"
            app:layout_constraintTop_toTopOf="@+id/button1" />

        <Button
            android:id="@+id/button3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="3"
            android:textSize="@dimen/button_size"
            app:layout_constraintBottom_toBottomOf="@+id/button2"
            app:layout_constraintEnd_toStartOf="@+id/guideline9"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toEndOf="@+id/button2"
            app:layout_constraintTop_toTopOf="@+id/button2" />

        <Button
            android:id="@+id/button4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="4"
            android:textSize="@dimen/button_size"
            app:layout_constraintBottom_toTopOf="@+id/guideline11"
            app:layout_constraintEnd_toStartOf="@+id/button5"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="@+id/guideline8"
            app:layout_constraintTop_toTopOf="@+id/guideline10" />

        <Button
            android:id="@+id/button5"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="5"
            android:textSize="@dimen/button_size"
            app:layout_constraintBottom_toBottomOf="@+id/button4"
            app:layout_constraintEnd_toStartOf="@+id/button6"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toEndOf="@+id/button4"
            app:layout_constraintTop_toTopOf="@+id/button4" />

        <Button
            android:id="@+id/button6"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="6"
            android:textSize="@dimen/button_size"
            app:layout_constraintBottom_toBottomOf="@+id/button5"
            app:layout_constraintEnd_toStartOf="@+id/guideline9"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toEndOf="@+id/button5"
            app:layout_constraintTop_toTopOf="@+id/button5" />

        <Button
            android:id="@+id/button7"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="7"
            android:textSize="@dimen/button_size"
            app:layout_constraintBottom_toTopOf="@+id/guideline12"
            app:layout_constraintEnd_toStartOf="@+id/button8"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="@+id/guideline8"
            app:layout_constraintTop_toTopOf="@+id/guideline11" />

        <Button
            android:id="@+id/button8"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="8"
            android:textSize="@dimen/button_size"
            app:layout_constraintBottom_toBottomOf="@+id/button7"
            app:layout_constraintEnd_toStartOf="@+id/button9"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toEndOf="@+id/button7"
            app:layout_constraintTop_toTopOf="@+id/button7" />

        <Button
            android:id="@+id/button9"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="9"
            android:textSize="@dimen/button_size"
            app:layout_constraintBottom_toBottomOf="@+id/button8"
            app:layout_constraintEnd_toStartOf="@+id/guideline9"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toEndOf="@+id/button8"
            app:layout_constraintTop_toTopOf="@+id/button8" />

        <Button
            android:id="@+id/clear"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Clear"
            android:textSize="@dimen/button_size"
            app:layout_constraintBottom_toTopOf="@+id/guideline7"
            app:layout_constraintEnd_toStartOf="@+id/button0"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="@+id/guideline8"
            app:layout_constraintTop_toTopOf="@+id/guideline12" />

        <Button
            android:id="@+id/button0"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="0"
            android:textSize="@dimen/button_size"
            app:layout_constraintBottom_toBottomOf="@+id/clear"
            app:layout_constraintEnd_toStartOf="@+id/submit"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toEndOf="@+id/clear"
            app:layout_constraintTop_toTopOf="@+id/clear" />

        <Button
            android:id="@+id/submit"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="OK"
            android:textSize="@dimen/button_size"
            app:layout_constraintBottom_toBottomOf="@+id/button0"
            app:layout_constraintEnd_toStartOf="@+id/guideline9"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toEndOf="@+id/button0"
            app:layout_constraintTop_toTopOf="@+id/button0" />
    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

　　成功页面：两个Textview一个Button来返回首页

<?xml version="1.0" encoding="utf-8"?>
<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">

    <data>
        <variable
            name="data"
            type="com.example.calculation.MyViewModel" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".WinFragment">

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline13"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.1" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline14"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.35" />

        <ImageView
            android:id="@+id/imageView2"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:contentDescription="@string/image_win"
            android:src="@drawable/ic_sentiment_satisfied_black_24dp"
            app:layout_constraintBottom_toTopOf="@+id/guideline14"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="@+id/guideline13" />

        <TextView
            android:id="@+id/textView10"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="恭喜你！创下新纪录"
            android:textSize="@dimen/bige_size"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="@+id/guideline14"
            app:layout_constraintVertical_bias="0.1" />

        <TextView
            android:id="@+id/textView11"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{@string/New_Score(data.highScore)}"
            android:textSize="@dimen/bige_size"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/imageView2"
            app:layout_constraintVertical_bias="0.3"
            tools:text="你的成绩是:%d" />

        <Button
            android:id="@+id/button10"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="返回"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.498"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="@+id/guideline14"
            app:layout_constraintVertical_bias="0.5" />
    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

　　失败页面：两个Textview一个Button来返回首页

<?xml version="1.0" encoding="utf-8"?>
<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">

    <data>
        <variable
            name="data"
            type="com.example.calculation.MyViewModel" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".LoseFragment">

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline15"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.1" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline16"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.35" />

        <ImageView
            android:id="@+id/imageView3"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:src="@drawable/ic_sentiment_dissatisfied_black_24dp"
            app:layout_constraintBottom_toTopOf="@+id/guideline16"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="@+id/guideline15" />

        <TextView
            android:id="@+id/textView13"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{@string/New_Score(data.currentScore)}"
            android:textSize="@dimen/bige_size"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="@+id/guideline16"
            app:layout_constraintVertical_bias="0.3"
            tools:text="你的成绩是:%d" />

        <Button
            android:id="@+id/button11"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="返回"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.498"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="@+id/guideline16"
            app:layout_constraintVertical_bias="0.5" />

        <TextView
            android:id="@+id/textView14"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="挑战失败!"
            android:textSize="@dimen/bige_size"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/imageView3"
            app:layout_constraintVertical_bias="0.1" />
    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>