保存 ArrayList 项 [关闭]

Question

我正在创建一个应用程序，我必须在其中一遍又一遍地引用相同的数据。我是编码新手，所以我不知道我是否做得正确。现在我用 setter 和 getter 创建了一个类来存储我想要的数据。

（物品类）

    public class PlayerList {
    private String score;
    private String team;
    private String name;
    private String scoreWeek;
    private String position;
    private String goals;
    private String assists;
    private String yellowCards;
    private String redCards;
    private int iconID;
    public PlayerList(String name, String team, String score, String scoreWeek, String position,
            String goals, String assists, String yellowCards, String redCards, int iconID){
        super();
        this.score= score;
        this.team = team;
        this.name = name;
        this.scoreWeek = scoreWeek;
        this.position= position;
        this.goals = goals;
        this.assists = assists;
        this.yellowCards = yellowCards;
        this.redCards = redCards;
        this.iconID= iconID;
    }
    public String getScore() {
        return score;
    }
    public void setScore(String score) {
        this.score = score;
    }
    public String getTeam() {
        return team;
    }
    public void setTeam(String team) {
        this.team = team;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getScoreWeek() {
        return scoreWeek;
    }
    public void setScoreWeek(String scoreWeek) {
        this.scoreWeek = scoreWeek;
    }
    public String getPosition() {
        return position;
    }
    public void setPosition(String position) {
        this.position = position;
    }
    public String getGoals() {
        return goals;
    }
    public void setGoals(String goals) {
        this.goals = goals;
    }
    public String getAssists() {
        return assists;
    }
    public void setAssists(String assists) {
        this.assists = assists;
    }
    public String getYellowCards() {
        return yellowCards;
    }
    public void setYellowCards(String yellowCards) {
        this.yellowCards = yellowCards;
    }
    public String getRedCards() {
        return redCards;
    }
    public void setRedCards(String redCards) {
        this.redCards = redCards;
    }
    public int getIconID() {
        return iconID;
    }
    public void setIconID(int iconID) {
        this.iconID = iconID;
    }
}

然后我创建了另一个类，在其中编辑这些数据并将其放入一个数组中。

（编辑代码）

 public class Players extends Activity {
    private ArrayList<PlayerList> stateList  = new ArrayList<PlayerList>();


    public Players(){
        PlayerList _states = new PlayerList("Name","Team","Score","Score Week", "Position",
                "Goals", "Assists","Yellow Cards","Red Cards", R.drawable.client_icon);
        stateList.add(_states);

        PlayerList _states1 = new PlayerList("Name2","Team","Score","Score Week", "Position",
                "Goals", "Assists","Yellow Cards","Red Cards", R.drawable.client_icon);
        stateList.add(_states1);

        PlayerList _states2 = new PlayerList("Name3","Team","Score","Score Week", "Position",
                "Goals", "Assists","Yellow Cards","Red Cards", R.drawable.client_icon);
        stateList.add(_states2);

    }
}

在编辑数据并将其添加到单独的数组 List 之后，我如何才能引用回数据。例如，在应用程序的其他部分中，我需要参考玩家的分数？我想将数据保存在 SharedPreferences 中，但它只保存集合。请帮忙。我想将它发送到另一个活动。例如，我希望它在主屏幕上显示玩家得分。以及在谈论球队球员的屏幕上。

Answer 1

如果您不想将数据直接传递给使用它的函数，则必须将其保存在某个地方。这称为数据持久性。这通常意味着该进程将在它创建的数据之前终止。在 Java 中，该术语用于泛指在事件甚至方法调用之间持续存在的数据，不一定是进程。在 Java 中，持久性通常使用序列化来完成。你可以让你的班级Serializable 像这样

public class MyClass implements Serializable { }

只有当它包含的每个对象都是可序列化的时，才能使对象可序列化。一旦一个对象是可序列化的，它就可以被写入和读取一个流（可能是一个文件）。然后其他代码可以检索序列化数据。 ObjectOutputStream 和 ObjectInputStream 能够读写可序列化的数据。在将对象读回适当的类型时，您必须将它们强制转换。

如果我读错了你的问题，而你真的不知道如何访问你的ArrayList，试试这个：

int score = null;
for (PlayerList pl: myArrayList) {
    if(pl.getName() == teamName)
        score = pl.getScore();
}
System.out.println(score == null ? "No score available.": score);

或者，要获得所有团队的分数：

for (PlayerList pl: myArrayList) {
    System.out.println(pl.getScore());
}