@Override是什么艺术

@override是Java中的一个注解，用来标注一个方法覆盖了父类中的同名方法。当子类继承父类并重写父类中的方法时，如果在子类的方法上添加了@Override注解，Java编译器会检查该注解标注的方法是否满足以下条件：

1. 方法的名称、参数列表、返回类型必须与父类中被重写的方法一致；

2. 子类方法的访问权限不能低于父类方法的访问权限。

如果以上两个条件都满足，则表示子类方法成功地覆盖了父类方法。使用@Override注解可以提高代码的可读性和可维护性，同时也能帮助开发人员避免一些常见的错误，比如写错方法名或使用错误的参数列表。

相关问题

android艺术般的控件,Android RecyclerView 使用完全解析 体验艺术般的控件

Android RecyclerView 是一款高度可定制化的控件，可用于展示大量数据列表。相比于 ListView，RecyclerView 具有更好的性能和更强的灵活性。以下是 Android RecyclerView 的使用完全解析：

1. 添加依赖

在项目的 build.gradle 文件中添加 RecyclerView 的依赖：

dependencies {
    implementation 'androidx.recyclerview:recyclerview:1.2.0'
}

2. 创建 RecyclerView

在布局文件中添加 RecyclerView 控件：

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/recyclerView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

3. 创建 Adapter

Adapter 是 RecyclerView 显示数据的桥梁，需要继承 RecyclerView.Adapter 类，并实现以下方法：

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {

    // 数据源
    private List<String> mData;

    public MyAdapter(List<String> data) {
        mData = data;
    }

    // 创建 ViewHolder
    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_layout, parent, false);
        return new ViewHolder(view);
    }

    // 绑定数据
    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.mTextView.setText(mData.get(position));
    }

    // 返回数据源大小
    @Override
    public int getItemCount() {
        return mData.size();
    }

    // ViewHolder
    static class ViewHolder extends RecyclerView.ViewHolder {

        TextView mTextView;

        ViewHolder(View itemView) {
            super(itemView);
            mTextView = itemView.findViewById(R.id.text);
        }
    }
}

4. 设置 LayoutManager

LayoutManager 用于管理 RecyclerView 的布局，它可以是 LinearLayoutManager、GridLayoutManager 或 StaggeredGridLayoutManager 等。以下是使用 LinearLayoutManager 的示例：

LinearLayoutManager layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);

5. 设置 Adapter

将 Adapter 设置到 RecyclerView 中：

MyAdapter adapter = new MyAdapter(data);
recyclerView.setAdapter(adapter);

6. 添加 ItemDecoration

ItemDecoration 可以为 RecyclerView 中的每个 Item 添加分割线、间距等效果。以下是添加分割线的示例：

DividerItemDecoration decoration = new DividerItemDecoration(this, DividerItemDecoration.VERTICAL);
recyclerView.addItemDecoration(decoration);

7. 添加 ItemAnimator

ItemAnimator 可以为 RecyclerView 中的每个 Item 添加动画效果。以下是添加默认 ItemAnimator 的示例：

recyclerView.setItemAnimator(new DefaultItemAnimator());

以上就是 Android RecyclerView 的完全使用解析。通过对 RecyclerView 的灵活使用，可以打造出各种艺术般的控件效果。

高考生主要分为文科生与理科生，文科生的考试科目为：语文、外语、数学和文综，理科生的考试科目为：语文、外语、数学和理综。但是参加高考考试的还有一部分考生称为艺体生，他们除了参加文化课考试外还要参加专业考试。要求使用Java语言的继承的思想设计类，使用类创建一组对象，表示不同类别的高考生信息，按普通文科生、普通理科生、文科艺术生、理科艺术生、文科体育生、理科体育生类别，按总分由高到低的顺序输出考生信息（考号、姓名、四门课成绩与总分），对于普通考生类别而言，如果总分相同，则按考号由小到大顺序输出；对于艺体生类别而言，如果总分（含专业课成绩）相同，则按专业课成绩由高到低的顺序输出，若专业课成绩也相同则按考号由小到大的顺序输出。 要求使用类的继承完成程序设计。 输入：普通文理生人数，普通文理生信息，艺体生人数，艺体生信息（普通文理生文理分类要求：1-文，2-理；艺体生先有文理分类，再有艺术、体育分类：1-艺术，2-体育） 输出：排序后的考生信息包括：学号,姓名,各科分数,总分,类别

import java.util.*;

class Student {
private int id;
private String name;
private int chinese;
private int math;
private int english;
private int totalScore;

public Student(int id, String name, int chinese, int math, int english) {
this.id = id;
this.name = name;
this.chinese = chinese;
this.math = math;
this.english = english;
this.totalScore = chinese + math + english;
}

public int getId() {
return id;
}

public String getName() {
return name;
}

public int getChinese() {
return chinese;
}

public int getMath() {
return math;
}

public int getEnglish() {
return english;
}

public int getTotalScore() {
return totalScore;
}

public String getCategory() {
return "";
}

@Override
public String toString() {
return id + "," + name + "," + chinese + "," + math + "," + english + "," + totalScore + "," + getCategory();
}
}

class ArtStudent extends Student {
private int artScore;

public ArtStudent(int id, String name, int chinese, int math, int english, int artScore) {
super(id, name, chinese, math, english);
this.artScore = artScore;
this.totalScore += artScore;
}

public int getArtScore() {
return artScore;
}

public String getCategory() {
return "艺术生";
}

@Override
public String toString() {
return super.toString() + "," + artScore;
}
}

class SportsStudent extends Student {
private int sportsScore;

public SportsStudent(int id, String name, int chinese, int math, int english, int sportsScore) {
super(id, name, chinese, math, english);
this.sportsScore = sportsScore;
this.totalScore += sportsScore;
}

public int getSportsScore() {
return sportsScore;
}

public String getCategory() {
return "体育生";
}

@Override
public String toString() {
return super.toString() + "," + sportsScore;
}
}

class ArtsStudent extends Student {
public ArtsStudent(int id, String name, int chinese, int math, int english) {
super(id, name, chinese, math, english);
}

public String getCategory() {
return "文科艺术生";
}
}

class ScienceStudent extends Student {
public ScienceStudent(int id, String name, int chinese, int math, int english) {
super(id, name, chinese, math, english);
}

public String getCategory() {
return "文科理科生";
}
}

class ArtScienceStudent extends Student {
private int artScore;

public ArtScienceStudent(int id, String name, int chinese, int math, int english, int artScore) {
super(id, name, chinese, math, english);
this.artScore = artScore;
this.totalScore += artScore;
}

public int getArtScore() {
return artScore;
}

public String getCategory() {
return "理科艺术生";
}

@Override
public String toString() {
return super.toString() + "," + artScore;
}
}

class SportsScienceStudent extends Student {
private int sportsScore;

public SportsScienceStudent(int id, String name, int chinese, int math, int english, int sportsScore) {
super(id, name, chinese, math, english);
this.sportsScore = sportsScore;
this.totalScore += sportsScore;
}

public int getSportsScore() {
return sportsScore;
}

public String getCategory() {
return "理科体育生";
}

@Override
public String toString() {
return super.toString() + "," + sportsScore;
}
}

public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);

int n = scanner.nextInt(); // 普通文理生人数
List<Student> students = new ArrayList<>();

// 输入普通文理生信息
for (int i = 0; i < n; i++) {
int id = scanner.nextInt();
String name = scanner.next();
int chinese = scanner.nextInt();
int math = scanner.nextInt();
int english = scanner.nextInt();
int category = scanner.nextInt();

if (category == 1) {
students.add(new ArtsStudent(id, name, chinese, math, english));
} else {
students.add(new ScienceStudent(id, name, chinese, math, english));
}
}

int m = scanner.nextInt(); // 艺体生人数

// 输入艺体生信息
for (int i = 0; i < m; i++) {
int id = scanner.nextInt();
String name = scanner.next();
int chinese = scanner.nextInt();
int math = scanner.nextInt();
int english = scanner.nextInt();
int category = scanner.nextInt();
int score = scanner.nextInt();

if (category == 1) {
students.add(new ArtStudent(id, name, chinese, math, english, score));
} else {
students.add(new SportsStudent(id, name, chinese, math, english, score));
}
}

// 按总分由高到低排序
Collections.sort(students, new Comparator<Student>() {
@Override
public int compare(Student s1, Student s2) {
if (s1.getTotalScore() != s2.getTotalScore()) {
return s2.getTotalScore() - s1.getTotalScore();
} else {
if (s1 instanceof ArtStudent && s2 instanceof ArtStudent) {
if (((ArtStudent) s1).getArtScore() != ((ArtStudent) s2).getArtScore()) {
return ((ArtStudent) s2).getArtScore() - ((ArtStudent) s1).getArtScore();
} else {
return s1.getId() - s2.getId();
}
} else if (s1 instanceof SportsStudent && s2 instanceof SportsStudent) {
if (((SportsStudent) s1).getSportsScore() != ((SportsStudent) s2).getSportsScore()) {
return ((SportsStudent) s2).getSportsScore() - ((SportsStudent) s1).getSportsScore();
} else {
return s1.getId() - s2.getId();
}
} else {
return s1.getId() - s2.getId();
}
}
}
});

// 输出考生信息
for (Student student : students) {
System.out.println(student);
}
}
}