多次打印ArrayList的內容時遇到問題

Question

這是我第一次在這里發布信息，我對編程還是很陌生（不久前才剛開始Java），因此，大家可以給我有關如何解決問題的任何建議，我們將不勝感激！ 希望我在第一篇文章中遵循此處的指導原則！

在該項目的宏偉計划中，我正在嘗試對“團隊”進行排序，以確定誰擁有與馬拉松相關的“圈數，車手和捐款”最多的人。 Team類由Rider對象組成。

這是我使用Team類中存在的方法遍歷Team數組的循環。

ArrayList<Team> team = new ArrayList<Team>();

for(int i=0; i<team.size(); i++){
        team.get(i).mostDonations(team);
        team.get(i).mostLaps(team);
        team.get(i).mostRiders(team);
    }

這是我的團隊課。 它充滿了必需的構造函數，setter和getter以及計算總計的方法。 但是，我認為下面應該是相關的代碼行。 （讓我知道我是否遺漏了任何東西！）

public class Team {
private String teamName;
private String teamAbbreviation;
private ArrayList<Riders> riders = new ArrayList<Riders>();
DecimalFormat decimal = new DecimalFormat("#0.00");

public double totalDonations(){
    double totalDonations = 0;
    for(int i=0; i < riders.size(); i++){
        totalDonations += riders.get(i).getAmount();
    }
    return totalDonations;
}

public int totalLaps(){
    int totalLaps = 0;
    for (int i = 0; i < riders.size(); i++){
        totalLaps += riders.get(i).getLaps();
    }
    return totalLaps;
}

public int totalRiders(){
    int totalRiders = 0;
    for (int i =0; i < riders.size(); i++){
        totalRiders += riders.size();
    }
    return totalRiders;
}

public void mostLaps(ArrayList<Team> Teams){
    int max = 0;
    int indexOfMax = 0;
    for(int i=0; i < Teams.size(); i++){
        if(Teams.get(i).totalDonations() > max){
            max = Teams.get(i).totalLaps();
            indexOfMax = i;
        }
    }
    System.out.println("The team with the most laps is: " + Teams.get(indexOfMax).getName() + "!");
}

public void mostRiders(ArrayList<Team> Teams){
    int max = 0;
    int indexOfMax = 0;
    for(int i=0; i < Teams.size(); i++){
        if(Teams.get(i).totalRiders() > max){
            max = Teams.get(i).totalRiders();
            indexOfMax = i;
        }
    }
    System.out.println("The team with the most riders is: " + Teams.get(indexOfMax).getName() + "!");
}

public void mostDonations(ArrayList<Team> Teams){
    double max = 0.0;
    int indexOfMax = 0;
    for(int i=0; i < Teams.size(); i++){
        if(Teams.get(i).totalDonations() > max){
            max = Teams.get(i).totalDonations();
            indexOfMax = i;
        }
    }
    System.out.println("The team with the most donations is: " + Teams.get(indexOfMax).getName() + "!");
}

這是我的騎士課。

public class Riders {

private String name;
private String hometown;
private String id;
private int laps;
private double amountRaised;

public Riders(){
    name = "";
    hometown = "";
    id = "";
    laps = 0;
    amountRaised = 0.0;
}

public Riders(String Name, String Hometown, String ID, int Laps){
    name = Name;
    hometown = Hometown;
    id = ID;
    laps = Laps;
    amountRaised = 0.0;
}

public void setName(String Name){
    name = Name;
}

public void setHometown(String Hometown){
    hometown = Hometown;
}

public void setAbbreviation(String ID){
    id = ID;
}

public void setLaps(int Laps){
    laps = Laps;
}

public void setAmount(double Amount){
    amountRaised = Amount;
}

public String getName(){
    return name;
}

public String getHometown(){
    return hometown;
}

public String getID(){
    return id;
}

public int getLaps(){
    return laps;
}

public double getAmount(){
    return amountRaised;
}
public String toString(){
    String s = "Rider Name: " + name + "\nHometown: " + hometown + "\nID: " + id + "\nLaps: " + laps;
    return s;
}

}

但是，輸出看起來像這樣：

捐款最多的團隊是：斑馬軍團成員！

圈數最大的團隊是：Xtremely Together！

騎手最多的團隊是：斑馬軍人！

捐款最多的團隊是：斑馬軍團成員！

圈數最大的團隊是：Xtremely Together！

騎手最多的團隊是：斑馬軍人！

捐款最多的團隊是：斑馬軍團成員！

圈數最大的團隊是：Xtremely Together！

騎手最多的團隊是：斑馬軍人！

捐款最多的團隊是：斑馬軍團成員！

圈數最大的團隊是：Xtremely Together！

騎手最多的團隊是：斑馬軍人！

捐款最多的團隊是：斑馬軍團成員！

圈數最大的團隊是：Xtremely Together！

騎手最多的團隊是：斑馬軍人！

捐款最多的團隊是：斑馬軍團成員！

圈數最大的團隊是：Xtremely Together！

騎手最多的團隊是：斑馬軍人！

捐款最多的團隊是：斑馬軍團成員！

圈數最大的團隊是：Xtremely Together！

騎手最多的團隊是：斑馬軍人！

捐款最多的團隊是：斑馬軍團成員！

圈數最大的團隊是：Xtremely Together！

騎手最多的團隊是：斑馬軍人！

捐款最多的團隊是：斑馬軍團成員！

圈數最大的團隊是：Xtremely Together！

騎手最多的團隊是：斑馬軍人！

捐款最多的團隊是：斑馬軍團成員！

圈數最大的團隊是：Xtremely Together！

騎手最多的團隊是：斑馬軍人！

我很困惑為什么要一遍又一遍地打印相同的三行。 我希望有人能指出我正確的方向。

Answer 1

下面的循環遍歷您的ArrayList<Team>並為每個Team項目打印三行。

for(int i=0; i<team.size(); i++){
    team.get(i).mostDonations(team);
    team.get(i).mostLaps(team);
    team.get(i).mostRiders(team);
}

---

現在，您還將使team經歷上述循環。

for(int i=0; i < Teams.size(); i++){
    if(Teams.get(i).totalDonations() > max){
        max = Teams.get(i).totalDonations(); // always goes for the max team object
        indexOfMax = i;
    }
}

---

更新：一種快速的方法是刪除調用這三個方法的for循環。

if(team != null) {
    team.get(0).mostDonations(team);
    team.get(0).mostLaps(team);
    team.get(0).mostRiders(team);
}

我將驗證這對您的代碼有多有效。

Answer 2

您對編程了解的越多，設計就越重要。 我仍然認為您的課程設計糟糕。 我創建了一個小應用程序來演示稍微更好的設計。

團隊班：

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package javaapplication16;

import java.util.*;

/**
 *
 * @author Sedrick
 */
public class Team {

    private String teamName;
    private List<String> playerName;
    private List<Integer> age;
    private int numOfMembers;
    private double membersAverageAge;

    public Team(String teamName, List<String> playerName, List<Integer> age)
    {
        this.teamName = teamName;
        this.playerName = playerName;
        this.age = age;
        this.numOfMembers = playerName.size();
        this.membersAverageAge = caculateAvgAge(this.age);
    }

    private static double caculateAvgAge(List<Integer> age)
    {
        int sum = 0;

        if (age.size() > 0) {
            for (int i = 0; i < age.size(); i++) {
                sum += age.get(i);
            }
        }
        else {
            return Double.NaN;
        }

        return (double) sum / (double) age.size();
    }

    /**
     * @return the teamName
     */
    public String getTeamName()
    {
        return teamName;
    }

    /**
     * @param teamName the teamName to set
     */
    public void setTeamName(String teamName)
    {
        this.teamName = teamName;
    }

    /**
     * @return the playerName
     */
    public List<String> getPlayerName()
    {
        return playerName;
    }

    /**
     * @param playerName the playerName to set
     */
    public void setPlayerName(List<String> playerName)
    {
        this.playerName = playerName;
    }

    /**
     * @return the age
     */
    public List<Integer> getAge()
    {
        return age;
    }

    /**
     * @param age the age to set
     */
    public void setAge(List<Integer> age)
    {
        this.age = age;
    }

    /**
     * @return the numOfMembers
     */
    public int getNumOfMembers()
    {
        return numOfMembers;
    }

    /**
     * @param numOfMembers the numOfMembers to set
     */
    public void setNumOfMembers(int numOfMembers)
    {
        this.numOfMembers = numOfMembers;
    }

    /**
     * @return the membersAverageAge
     */
    public double getMembersAverageAge()
    {
        return membersAverageAge;
    }

    /**
     * @param membersAverageAge the membersAverageAge to set
     */
    public void setMembersAverageAge(double membersAverageAge)
    {
        this.membersAverageAge = membersAverageAge;
    }

}

主類：

import java.util.*;

/**
 *
 * @author Sedrick
 */
public class JavaApplication16 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args)
    {
        // TODO code application logic here
        List<String> cowPlayer = new ArrayList();
        List<Integer> cowPlayerAge = new ArrayList();
        cowPlayer.add("Tim");
        cowPlayerAge.add(20);
        cowPlayer.add("Jane");
        cowPlayerAge.add(23);
        cowPlayer.add("Kim");
        cowPlayerAge.add(25);
        cowPlayer.add("Chris");
        cowPlayerAge.add(10);

        Team cow = new Team("Cows", cowPlayer, cowPlayerAge);

        List<String> frogPlayer = new ArrayList();
        List<Integer> frogPlayerAge = new ArrayList();
        frogPlayer.add("Dana");
        frogPlayerAge.add(21);
        frogPlayer.add("Jack");
        frogPlayerAge.add(19);
        frogPlayer.add("Jill");
        frogPlayerAge.add(30);

        Team frog = new Team("Frogs", frogPlayer, frogPlayerAge);

        System.out.println(cow.getTeamName() + " info");
        System.out.println("\tNumber of members: " + cow.getNumOfMembers());
        System.out.println("\tNumber of members: " + cow.getMembersAverageAge());
        System.out.println("\tPlayers Name and Age");
        for (int i = 0; i < cow.getPlayerName().size(); i++) {
            System.out.println("\t\t" + cow.getPlayerName().get(i) + " - " + cow.getAge().get(i));
        }

        System.out.println(frog.getTeamName() + " info");
        System.out.println("\tNumber of members: " + frog.getNumOfMembers());
        System.out.println("\tNumber of members: " + frog.getMembersAverageAge());
        System.out.println("\tPlayers Name and Age");
        for (int i = 0; i < frog.getPlayerName().size(); i++) {
            System.out.println("\t\t" + frog.getPlayerName().get(i) + " - " + frog.getAge().get(i));
        }

        List<Team> teams = new ArrayList();
        teams.add(cow);
        teams.add(frog);

        System.out.println("Team with the most players: " + whichTeamHasTheMostPlayers(teams));
        System.out.println("Team whose players average age is higher: " + whichTeamHasTheHighestAverageAge(teams));

    }

    //If there are more than one team with the same number of players this will not work correctly.
    static private String whichTeamHasTheMostPlayers(List<Team> teams)
    {

        int mostPlayersIndex = 0;//assume the first team has the most players;
        int amountOfPlayers = teams.get(0).getNumOfMembers();
        for (int i = 1; i < teams.size(); i++) {
            if (teams.get(i).getNumOfMembers() > amountOfPlayers) {
                mostPlayersIndex = i;
                amountOfPlayers = teams.get(i).getNumOfMembers();
            }
        }

        return teams.get(mostPlayersIndex).getTeamName();
    }

    //If there are more than one team with the same average this will not work correctly.
    static private String whichTeamHasTheHighestAverageAge(List<Team> teams)
    {
        int highestAvgIndex = 0;//assume the first team has the most players;
        double teamAvg = teams.get(0).getMembersAverageAge();
        for (int i = 1; i < teams.size(); i++) {
            if (teams.get(i).getMembersAverageAge() > highestAvgIndex) {
                highestAvgIndex = i;
                teamAvg = teams.get(i).getMembersAverageAge();
            }
        }

        return teams.get(highestAvgIndex).getTeamName();
    }

}