篮球比赛计分器

阶段小结——做一个篮球比赛计分器

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创建项目

界面设计

首先将应用配置为使用数据绑定

android {
        ...
        dataBinding {
            enabled = true
        }
    }

界面设置为数据绑定类型的Layout

convert to data binding Layout

<?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="score"
                type="com.example.score.ScoreViewModel" />
    </data>

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

        <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="0.5" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.05" />

        <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="0.15" />

        <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="0.35" />

        <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="0.5" />

        <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="0.65" />

        <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" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline8"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.9" />

        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/textview_TeamA"
            android:textSize="@dimen/TeamFontSize"
            app:layout_constraintBottom_toTopOf="@+id/guideline3"
            app:layout_constraintEnd_toStartOf="@+id/guideline"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="@+id/guideline2" />

        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/textview_TeamB"
            android:textSize="@dimen/TeamFontSize"
            app:layout_constraintBottom_toTopOf="@+id/guideline3"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="@+id/guideline"
            app:layout_constraintTop_toTopOf="@+id/guideline2" />

        <TextView
            android:id="@+id/textView3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{String.valueOf(score.getaTeamScore())}"
            android:textColor="@color/colorAccent"
            android:textSize="@dimen/ScoreFontSize"
            app:layout_constraintBottom_toTopOf="@+id/guideline4"
            app:layout_constraintEnd_toStartOf="@+id/guideline"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="@+id/guideline3"
            tools:text="110" />

        <TextView
            android:id="@+id/textView4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{String.valueOf(score.getbTeamScore())}"
            android:textColor="@color/colorPrimary"
            android:textSize="@dimen/ScoreFontSize"
            app:layout_constraintBottom_toTopOf="@+id/guideline4"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="@+id/guideline"
            app:layout_constraintTop_toTopOf="@+id/guideline3"
            tools:text="111" />

        <Button
            android:id="@+id/button"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:background="@color/colorAccent"
            android:text="@string/button1"
            android:textColor="@android:color/white"
            android:textSize="@dimen/buttonSize"
            android:onClick="@{()->score.aTeamAdd(1)}"
            app:layout_constraintBottom_toTopOf="@+id/guideline5"
            app:layout_constraintEnd_toStartOf="@+id/guideline"
            app:layout_constraintStart_toStartOf="@+id/guideline9"
            app:layout_constraintTop_toTopOf="@+id/guideline4" />

        <Button
            android:id="@+id/button2"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:background="@color/colorPrimary"
            android:text="@string/button1"
            android:textColor="@android:color/white"
            android:textSize="@dimen/buttonSize"
            android:onClick="@{()->score.bTeamAdd(1)}"
            app:layout_constraintBottom_toTopOf="@+id/guideline5"
            app:layout_constraintEnd_toStartOf="@+id/guideline10"
            app:layout_constraintStart_toStartOf="@+id/guideline"
            app:layout_constraintTop_toTopOf="@+id/guideline4" />

        <Button
            android:id="@+id/button3"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:background="@color/colorAccent"
            android:text="@string/button2"
            android:textColor="@android:color/white"
            android:textSize="@dimen/buttonSize"
            android:onClick="@{()->score.aTeamAdd(2)}"
            app:layout_constraintBottom_toTopOf="@+id/guideline6"
            app:layout_constraintEnd_toStartOf="@+id/guideline"
            app:layout_constraintStart_toStartOf="@+id/guideline9"
            app:layout_constraintTop_toTopOf="@+id/guideline5" />

        <Button
            android:id="@+id/button4"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:background="@color/colorPrimary"
            android:text="@string/button2"
            android:textColor="@android:color/white"
            android:textSize="@dimen/buttonSize"
            android:onClick="@{()->score.bTeamAdd(2)}"
            app:layout_constraintBottom_toTopOf="@+id/guideline6"
            app:layout_constraintEnd_toStartOf="@+id/guideline10"
            app:layout_constraintStart_toStartOf="@+id/guideline"
            app:layout_constraintTop_toTopOf="@+id/guideline5" />

        <Button
            android:id="@+id/button5"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:background="@color/colorAccent"
            android:text="@string/button3"
            android:textColor="@android:color/white"
            android:textSize="@dimen/buttonSize"
            android:onClick="@{()->score.aTeamAdd(3)}"
            app:layout_constraintBottom_toTopOf="@+id/guideline7"
            app:layout_constraintEnd_toStartOf="@+id/guideline"
            app:layout_constraintStart_toStartOf="@+id/guideline9"
            app:layout_constraintTop_toTopOf="@+id/guideline6" />

        <Button
            android:id="@+id/button6"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:background="@color/colorPrimary"
            android:text="@string/button3"
            android:textColor="@android:color/white"
            android:textSize="@dimen/buttonSize"
            android:onClick="@{()->score.bTeamAdd(3)}"
            app:layout_constraintBottom_toTopOf="@+id/guideline7"
            app:layout_constraintEnd_toStartOf="@+id/guideline10"
            app:layout_constraintStart_toStartOf="@+id/guideline"
            app:layout_constraintTop_toTopOf="@+id/guideline6" />

        <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="0.05109489" />

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline10"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            app:layout_constraintGuide_percent="0.95" />

        <ImageButton
            android:id="@+id/imageButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:contentDescription="@string/undoButton"
            android:onClick="@{()->score.undo()}"
            app:layout_constraintBottom_toTopOf="@+id/guideline8"
            app:layout_constraintEnd_toStartOf="@+id/guideline"
            app:layout_constraintHorizontal_bias="0.8"
            app:layout_constraintStart_toStartOf="@+id/guideline9"
            app:layout_constraintTop_toTopOf="@+id/guideline7"
            app:srcCompat="@drawable/ic_undo_black_24dp" />

        <ImageButton
            android:id="@+id/imageButton2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:contentDescription="@string/resetButton"
            android:onClick="@{()->score.reset()}"
            app:layout_constraintBottom_toTopOf="@+id/guideline8"
            app:layout_constraintEnd_toStartOf="@+id/guideline10"
            app:layout_constraintHorizontal_bias="0.2"
            app:layout_constraintStart_toStartOf="@+id/guideline"
            app:layout_constraintTop_toTopOf="@+id/guideline7"
            app:srcCompat="@drawable/ic_loop_black_24dp" />
    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

创建ViewModel类

创建一个ScoreViewModel类

代码如下

package com.example.score;

import androidx.lifecycle.MutableLiveData;
import androidx.lifecycle.ViewModel;

public class ScoreViewModel extends ViewModel {
    private MutableLiveData<Integer> aTeamScore;
    private MutableLiveData<Integer> bTeamScore;
    private int aBack,bBack;

    public MutableLiveData<Integer> getaTeamScore() {
        if(aTeamScore == null){
            aTeamScore = new MutableLiveData<>();
            aTeamScore.setValue(0);
        }
        return aTeamScore;
    }

    public MutableLiveData<Integer> getbTeamScore() {
        if (bTeamScore == null){
            bTeamScore = new MutableLiveData<>();
            bTeamScore.setValue(0);
        }
        return bTeamScore;
    }

    /*
     *在Edit工具栏中有一个
     * Column Selection Mode
     * 可以实现多行代码同时更改
     * （快捷键Alt+Shift+Insert）
     */

    //A队加分
    public void aTeamAdd(int p){
        aBack = aTeamScore.getValue();
        bBack = bTeamScore.getValue();
        aTeamScore.setValue(aTeamScore.getValue() + p);
    }

    //B队加分
    public void bTeamAdd(int p){
        aBack = aTeamScore.getValue();
        bBack = bTeamScore.getValue();
        bTeamScore.setValue(bTeamScore.getValue() + p);
    }

    //重置分数
    public void reset(){
        aBack = aTeamScore.getValue();
        bBack = bTeamScore.getValue();
        aTeamScore.setValue(0);
        bTeamScore.setValue(0);
    }

    //操作失误撤销
    public void undo(){
        aTeamScore.setValue(aBack);
        bTeamScore.setValue(bBack);
    }

}

在MainActivity中添加声明

1. 在此之前在gradle中添加依赖

dependencies {
	···
    implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'
}

2. 在MainActivity中添加声明

package com.example.score;

import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.DataBindingUtil;
import androidx.lifecycle.ViewModelProvider;

import android.os.Bundle;

import com.example.score.databinding.ActivityMainBinding;

public class MainActivity extends AppCompatActivity {
    ScoreViewModel scoreViewModel;
    ActivityMainBinding binding;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.activity_main);
        binding = DataBindingUtil.setContentView(this,R.layout.activity_main);
        scoreViewModel = new  ViewModelProvider(this).get(ScoreViewModel.class);
        binding.setScore(scoreViewModel);
        binding.setLifecycleOwner(this);
    }
}

3. 运行项目，无问题：
   
   
   

对界面进行优化（横屏优化）

发现横屏界面过于紧密，重新设置Land界面
创建Landscape Variation
可自行按照喜欢来设计

运行界面如下，无问题：

本地化

将手机设为中文环境
运行观察汉化之后的界面

横屏