Question

我有以下课程：https://paste.md-5.net/mozodifaka.java

我一直在第281行获得NPE。我一直在弄弄它好几个小时了，但我无法使它正常工作。您可以清楚地看到我正在使用landList = new ArrayList<>()对其进行初始化，因此landList仍然为空吗？

public class Kingdom extends OfflineKingdom implements KingdomEventHandler {

  private transient volatile List<KingdomPlayer> onlineMembers;// = new ArrayList<>();
  private transient volatile List<Kingdom> onlineEnemies;// = new ArrayList<>();
  private transient volatile List<Kingdom> onlineAllies;// = new ArrayList<>();
  private transient volatile int kingdomLand;// = 0;
  private transient volatile List<Land> landList;// = new ArrayList<>();
  private transient volatile int uptime;// = 2;
  private transient volatile Kingdom invader;
  private transient volatile Kingdom invading;
  private transient volatile long invasionStart;

  volatile Location nexus_loc;
  volatile Location home_loc;
  volatile int chestsize;// = 9;
  volatile long timestamp;// = 0;
  volatile int maxMember;// = 10;

  ChampionInfo championInfo;// = new ChampionInfo();
  PermissionsInfo permissionsInfo;// = new PermissionsInfo();
  ArmyInfo armyInfo;// = new ArmyInfo();
  AggressorInfo aggressorInfo;// = new AggressorInfo();
  MisupgradeInfo misupgradeInfo;// = new MisupgradeInfo();
  KingdomChest kingdomChest;// = new KingdomChest();
  PowerUp powerUp;// = new PowerUp();
  TurretUpgradeInfo turretUpgrades;// = new TurretUpgradeInfo();

  private boolean init = false;

  {
    onlineMembers = new ArrayList<>();
    onlineEnemies = new ArrayList<>();
    onlineAllies = new ArrayList<>();
    kingdomLand = 0;
    landList = new ArrayList<>();
    uptime = 2;

    chestsize = 9;
    timestamp = 0;
    maxMember = 10;

    championInfo = new ChampionInfo();
    permissionsInfo = new PermissionsInfo();
    armyInfo = new ArmyInfo();
    aggressorInfo = new AggressorInfo();
    misupgradeInfo = new MisupgradeInfo();
    kingdomChest = new KingdomChest();
    powerUp = new PowerUp();
    turretUpgrades = new TurretUpgradeInfo();

    init = true;
  }

  public Kingdom(String kingdomName) {
    super(kingdomName);
  }

  public void init() {
    if (init == (init = true)) return;
    onlineMembers = new ArrayList<>();
    onlineEnemies = new ArrayList<>();
    onlineAllies = new ArrayList<>();
    kingdomLand = 0;
    landList = new ArrayList<>();
    uptime = 2;

    chestsize = 9;
    timestamp = 0;
    maxMember = 10;

    championInfo = new ChampionInfo();
    permissionsInfo = new PermissionsInfo();
    armyInfo = new ArmyInfo();
    aggressorInfo = new AggressorInfo();
    misupgradeInfo = new MisupgradeInfo();
    kingdomChest = new KingdomChest();
    powerUp = new PowerUp();
    turretUpgrades = new TurretUpgradeInfo();
  }

  public int getLand() {
    init();
    int land = 0;
    for (final Land l : LandManager.landList.values()) {
        if (l.getOwner() == null || !l.getOwner().equals(getKingdomName())) continue;
        landList.add(l); // 281
        land++;
    }
    return land;
  }

  public List<Land> getLandList() {
    getLand();
    return landList;
  }

}

Answer 1

您正在寻找错误的ArrayList实例。

LandManager.landList

这是来自另一类List的静态 LandManager。

您要初始化的对象位于Kingdom内部。

landList = new ArrayList<>();

初始化列表后出现NullPointerException

1 个答案: