（一）四则运算APP版
这这个Demo的目的就是强化一下本周学习的Android的Jetpack里的新内容，接下来我将通过这个Demo来展示我所学到的新知识。
先列出新学到的知识：ViewModel，Navigation，MutableLiveData，ViewModelSaveState,SharedPreferences,AndroidViewModel,DataBinding
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，顶部还有一个最高分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：顶部一个textview代表目前的得分情况，中间是一个算式，下面是你的答案，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：一个Imageview笑脸，两个Textview还有一个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：一个Imageview哭脸，两个Textview还有一个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>
程序设计：
首先是设计我们的MyViewModel里的数据，有最高分，目前得分，左操作数，右操作数，操作符，答案
通过SharedPreferences来保存数据，livedata可以随时的刷新数据，故用它来显示数据。
package com.example.calculation; import android.app.Application;
import android.content.Context;
import android.content.SharedPreferences; import androidx.annotation.NonNull;
import androidx.lifecycle.AndroidViewModel;
import androidx.lifecycle.MutableLiveData;
import androidx.lifecycle.SavedStateHandle;
import androidx.lifecycle.ViewModel; import java.util.Random; public class MyViewModel extends AndroidViewModel {
private SavedStateHandle handle;
private static String KEY_HIGH_SCORE="key_high_score";
private static String KEY_LEFT_NUMBER="key_left_number";
private static String KEY_RIGHT_NUMBER="key_right_number";
private static String KEY_OPERATOR="key_operator";
private static String KEY_ANSWER="key_answer";
private static String SAVE_SHP_DATA_NAME="save_shp_data_name";
private static String KEY_CURRENT_SCORE="key_current_score";
public boolean win_flag=false; public MyViewModel(@NonNull Application application,SavedStateHandle handle) {
super(application);
if(!handle.contains(KEY_HIGH_SCORE)){
SharedPreferences shp=getApplication().getSharedPreferences(SAVE_SHP_DATA_NAME, Context.MODE_PRIVATE);
handle.set(KEY_HIGH_SCORE,shp.getInt(KEY_HIGH_SCORE,0));
handle.set(KEY_LEFT_NUMBER,0);
handle.set(KEY_RIGHT_NUMBER,0);
handle.set(KEY_OPERATOR,"+");
handle.set(KEY_ANSWER,0);
handle.set(KEY_CURRENT_SCORE,0);
}
this.handle=handle;
}
public MutableLiveData<Integer> getLeftNumber(){
return handle.getLiveData(KEY_LEFT_NUMBER);
}
public MutableLiveData<Integer> getRigthNumber(){
return handle.getLiveData(KEY_RIGHT_NUMBER);
}
public MutableLiveData<String> getOperator(){
return handle.getLiveData(KEY_OPERATOR);
}
public MutableLiveData<Integer> getHighScore(){
return handle.getLiveData(KEY_HIGH_SCORE);
}
public MutableLiveData<Integer> getCurrentScore(){
return handle.getLiveData(KEY_CURRENT_SCORE);
}
public MutableLiveData<Integer> getAnswer(){
return handle.getLiveData(KEY_ANSWER);
} public void setCurrentScore(){
handle.set(KEY_CURRENT_SCORE,0);
} void generator(){
int level=100;
Random random=new Random();
int a=random.nextInt(level)+1;
int b=random.nextInt(level)+1;
if(a%4==0){
getOperator().setValue("+");
if(a>b){
getAnswer().setValue(a);
getLeftNumber().setValue(b);
getRigthNumber().setValue(a-b);
}else{
getOperator().setValue("+");
getAnswer().setValue(b);
getLeftNumber().setValue(a);
getRigthNumber().setValue(b-a);
}
}
else if(a%4==1){
getOperator().setValue("-");
if(a>b){
getAnswer().setValue(a-b);
getLeftNumber().setValue(a);
getRigthNumber().setValue(b);
}else{
getOperator().setValue("-");
getAnswer().setValue(b-a);
getLeftNumber().setValue(b);
getRigthNumber().setValue(a);
}
}
else if(a%4==2){
getOperator().setValue("*");
getLeftNumber().setValue(a);
getRigthNumber().setValue(b);
getAnswer().setValue(a*b);
}
else if(a%4==3){
getOperator().setValue("/");
while(a%b!=0){
a=random.nextInt(level)+1;
b=random.nextInt(level)+1;
}
getLeftNumber().setValue(a);
getRigthNumber().setValue(b);
getAnswer().setValue(a/b);
}
}
void save(){
SharedPreferences shp=getApplication().getSharedPreferences(SAVE_SHP_DATA_NAME,Context.MODE_PRIVATE);
SharedPreferences.Editor editor=shp.edit();
editor.putInt(KEY_HIGH_SCORE,getHighScore().getValue());
editor.apply();
}
void answerCurrent(){
getCurrentScore().setValue(getCurrentScore().getValue()+1);
if(getCurrentScore().getValue()>getHighScore().getValue()){
getHighScore().setValue(getCurrentScore().getValue());
win_flag=true;
}
generator();
}
}
TieleFragment的设计：设计一个按钮的绑定事件，进行跳转到出题页面
package com.example.calculation; import android.app.AppComponentFactory;
import android.app.Application;
import android.content.pm.ApplicationInfo;
import android.os.Bundle; import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.DataBindingUtil;
import androidx.fragment.app.Fragment;
import androidx.lifecycle.SavedStateViewModelFactory;
import androidx.lifecycle.ViewModelProvider;
import androidx.lifecycle.ViewModelProviders;
import androidx.navigation.NavController;
import androidx.navigation.Navigation; import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup; import com.example.calculation.databinding.FragmentTitleBinding; /**
* A simple {@link Fragment} subclass.
*/
public class TitleFragment extends Fragment{ public TitleFragment() {
// Required empty public constructor
} @Override
public View onCreateView(@NonNull LayoutInflater inflater, final ViewGroup container,
Bundle savedInstanceState) { FragmentTitleBinding binding;
binding= DataBindingUtil.inflate(inflater,R.layout.fragment_title,container,false);
MyViewModel myViewModel = ViewModelProviders.of(requireActivity(), new SavedStateViewModelFactory(requireActivity().getApplication(),requireActivity())).get(MyViewModel.class);
binding.setData(myViewModel);
binding.setLifecycleOwner(requireActivity());
binding.button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
NavController controller=Navigation.findNavController(v);
controller.navigate(R.id.action_titleFragment_to_questionFragment);
}
});
return binding.getRoot();
// Inflate the layout for this fragment
//return inflater.inflate(R.layout.fragment_title, container, false);
} }
QuestionFragment的设计：通过按钮点击来获取用户的答案，然后从数据里获取当前的viewmodel，判断结果是否相同，之后进行相应的操作。
里面有代码注释
package com.example.calculation; import android.os.Bundle; import androidx.databinding.DataBindingUtil;
import androidx.fragment.app.Fragment;
import androidx.lifecycle.SavedStateViewModelFactory;
import androidx.lifecycle.ViewModelProvider;
import androidx.lifecycle.ViewModelProviders;
import androidx.navigation.NavController;
import androidx.navigation.Navigation; import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast; import com.example.calculation.databinding.FragmentQuestionBinding; /**
* A simple {@link Fragment} subclass.
*/
public class QuestionFragment extends Fragment { public QuestionFragment() {
// Required empty public constructor
} @Override
public View onCreateView(LayoutInflater inflater, final ViewGroup container,
Bundle savedInstanceState) {
final MyViewModel myViewModel;
myViewModel= ViewModelProviders.of(requireActivity(),new SavedStateViewModelFactory(requireActivity().getApplication(),requireActivity())).get(MyViewModel.class);
//获取运算表达式
myViewModel.generator();
//设置初始得分为0
myViewModel.setCurrentScore();
//获取页面的控制binding
final FragmentQuestionBinding binding;
binding= DataBindingUtil.inflate(inflater,R.layout.fragment_question,container,false);
//设置数据与生命周期
binding.setData(myViewModel);
binding.setLifecycleOwner(requireActivity());
//builder用来保存用户输入的数据
final StringBuilder builder=new StringBuilder();
View.OnClickListener listener=new View.OnClickListener() {
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.button0:
builder.append(0);
break;
case R.id.button1:
builder.append(1);
break;
case R.id.button2:
builder.append(2);
break;
case R.id.button3:
builder.append(3);
break;
case R.id.button4:
builder.append(4);
break;
case R.id.button5:
builder.append(5);
break;
case R.id.button6:
builder.append(6);
break;
case R.id.button7:
builder.append(7);
break;
case R.id.button8:
builder.append(8);
break;
case R.id.button9:
builder.append(9);
break;
case R.id.clear:
//清楚代表用户的输入长度未0
builder.setLength(0);
break;
}
if(builder.length()==0){
binding.textView9.setText("请输入你的答案：");
}else{
//显示到UI页面上
binding.textView9.setText(builder.toString());
}
}
};
//设置每一个按钮的点击事件
binding.button0.setOnClickListener(listener);
binding.button1.setOnClickListener(listener);
binding.button2.setOnClickListener(listener);
binding.button3.setOnClickListener(listener);
binding.button4.setOnClickListener(listener);
binding.button5.setOnClickListener(listener);
binding.button6.setOnClickListener(listener);
binding.button7.setOnClickListener(listener);
binding.button8.setOnClickListener(listener);
binding.button9.setOnClickListener(listener);
binding.clear.setOnClickListener(listener);
//提交按钮的设计
binding.submit.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(builder.length()!=0) {
//当答案相同时
if (Integer.valueOf(builder.toString()).intValue() == myViewModel.getAnswer().getValue()) {
myViewModel.answerCurrent();
builder.setLength(0);
binding.textView9.setText("回答正确! 请继续!");
} else {
NavController controller = Navigation.findNavController(v);
if (myViewModel.win_flag) {
//当创造新纪录时，进入成功页面
controller.navigate(R.id.action_questionFragment_to_winFragment);
myViewModel.win_flag = false;
myViewModel.save();
} else {
//否则进入失败页面
controller.navigate(R.id.action_questionFragment_to_loseFragment);
}
}
}else{
Toast.makeText(v.getContext(), "请输入答案", Toast.LENGTH_SHORT).show();
}
}
});
return binding.getRoot();
// Inflate the layout for this fragment
//return inflater.inflate(R.layout.fragment_question, container, false);
}
}
WinFragment的设计：设置它的返回按钮，与LoseFragment一样
package com.example.calculation; import android.os.Bundle; import androidx.databinding.DataBindingUtil;
import androidx.fragment.app.Fragment;
import androidx.lifecycle.SavedStateHandle;
import androidx.lifecycle.SavedStateViewModelFactory;
import androidx.lifecycle.ViewModelProvider;
import androidx.lifecycle.ViewModelProviders;
import androidx.navigation.NavController;
import androidx.navigation.Navigation; import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup; import com.example.calculation.databinding.FragmentWinBinding; /**
* A simple {@link Fragment} subclass.
*/
public class WinFragment extends Fragment { public WinFragment() {
// Required empty public constructor
} @Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
MyViewModel myViewModel;
myViewModel= ViewModelProviders.of(requireActivity(), new SavedStateViewModelFactory(requireActivity().getApplication(),requireActivity())).get(MyViewModel.class);
FragmentWinBinding binding;
binding= DataBindingUtil.inflate(inflater,R.layout.fragment_win,container,false);
binding.setData(myViewModel);
binding.setLifecycleOwner(requireActivity());
binding.button10.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
NavController controller= Navigation.findNavController(v);
controller.navigate(R.id.action_winFragment_to_titleFragment);
}
});
return binding.getRoot();
// Inflate the layout for this fragment
//return inflater.inflate(R.layout.fragment_win, container, false);
}
}
package com.example.calculation; import android.os.Bundle; import androidx.databinding.DataBindingUtil;
import androidx.fragment.app.Fragment;
import androidx.lifecycle.SavedStateViewModelFactory;
import androidx.lifecycle.ViewModelProvider;
import androidx.lifecycle.ViewModelProviders;
import androidx.navigation.NavController;
import androidx.navigation.Navigation; import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup; import com.example.calculation.databinding.FragmentLoseBinding; /**
* A simple {@link Fragment} subclass.
*/
public class LoseFragment extends Fragment { public LoseFragment() {
// Required empty public constructor
} @Override
public View onCreateView(LayoutInflater inflater, final ViewGroup container,
Bundle savedInstanceState) {
MyViewModel myViewModel;
myViewModel= ViewModelProviders.of(requireActivity(),new SavedStateViewModelFactory(requireActivity().getApplication(),requireActivity())).get(MyViewModel.class);
FragmentLoseBinding binding;
binding= DataBindingUtil.inflate(inflater,R.layout.fragment_lose,container,false);
binding.setData(myViewModel);
binding.setLifecycleOwner(requireActivity());
binding.button11.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
NavController controller= Navigation.findNavController(v);
controller.navigate(R.id.action_loseFragment_to_titleFragment);
}
});
return binding.getRoot();
// Inflate the layout for this fragment
//return inflater.inflate(R.layout.fragment_lose, container, false);
}
}
MainActivity的设计：用来设置左上角的返回与手机左下方左三角的返回
package com.example.calculation; import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.NavigationUI; import android.app.Dialog;
import android.content.DialogInterface;
import android.os.Bundle; public class MainActivity extends AppCompatActivity {
NavController controller;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
controller= Navigation.findNavController(this,R.id.fragment);
NavigationUI.setupActionBarWithNavController(this,controller);
}
//设置页面的左上角的返回操作
@Override
public boolean onSupportNavigateUp() {
if(controller.getCurrentDestination().getId()==R.id.questionFragment){
AlertDialog.Builder builder=new AlertDialog.Builder(this);
builder.setTitle("你确定要退出吗？");
builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
controller.navigateUp();
}
});
builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) { }
});
AlertDialog dialog=builder.create();
dialog.show();
}else{
controller.navigate(R.id.titleFragment);
}
return super.onSupportNavigateUp();
}
//设置手机的左三角的返回操作
@Override
public void onBackPressed() {
onSupportNavigateUp();
}
}
整个项目到此完结。。。
花费时间：
2020/3/29：上午10：00-11：10，休息10分钟，11：30-12：30，
2020/3/29：下午15：00-15：45，吃东西喝水10分钟，16：00-19：00，吃饭30分钟。
2020/3/29：晚上19：30-20：45，完成。
共花费：420分钟，代码量：450行，UI设计代码除外。