我对 ArrayList 和 Array 之间有点困惑,我理解变量是什么,但我不明白为什么我不能将 ArrayList 转换为 Array 并具有相同的效果。
我目前使用 ArrayList 时的这段代码
import java.util.Objects;
import com.google.gson.Gson;
import com.google.gson.JsonObject;
public final class NpcDefinitionLoader extends JsonLoader {
/**
* Creates a new {@link NpcDefinitionLoader}.
*/
public NpcDefinitionLoader() {
super(DefinitionEditor.fileChooser.getSelectedFile().getAbsolutePath());
}
@Override
public void load(JsonObject reader, Gson builder) {
int index = reader.get("id").getAsInt();
String name = Objects.requireNonNull(reader.get("name").getAsString());
String description = Objects.requireNonNull(reader.get("examine").getAsString());
int combatLevel = reader.get("combat").getAsInt();
int size = reader.get("size").getAsInt();
boolean attackable = reader.get("attackable").getAsBoolean();
boolean aggressive = reader.get("aggressive").getAsBoolean();
boolean retreats = reader.get("retreats").getAsBoolean();
boolean poisonous = reader.get("poisonous").getAsBoolean();
int respawnTime = reader.get("respawn").getAsInt();
int maxHit = reader.get("maxHit").getAsInt();
int hitpoints = reader.get("hitpoints").getAsInt();
int attackSpeed = reader.get("attackSpeed").getAsInt();
int attackAnim = reader.get("attackAnim").getAsInt();
int defenceAnim = reader.get("defenceAnim").getAsInt();
int deathAnim = reader.get("deathAnim").getAsInt();
int attackBonus = reader.get("attackBonus").getAsInt();
int meleeDefence = reader.get("defenceMelee").getAsInt();
int rangedDefence = reader.get("defenceRange").getAsInt();
int magicDefence = reader.get("defenceMage").getAsInt();
NPCDefinitions.definitions.get(index) = new NPCDefinitions(index, name, description, combatLevel, size, attackable, aggressive, retreats,
poisonous, respawnTime, maxHit, hitpoints, attackSpeed, attackAnim, defenceAnim, deathAnim, attackBonus, meleeDefence,
rangedDefence, magicDefence);
}
}
我在这里遇到错误
NPCDefinitions.definitions.get(index) = new NPCDefinitions(index, name, description, combatLevel, size, attackable, aggressive, retreats,
poisonous, respawnTime, maxHit, hitpoints, attackSpeed, attackAnim, defenceAnim, deathAnim, attackBonus, meleeDefence,
rangedDefence, magicDefence);
说左边一定是一个变量。当我使用这样的数组时
NPCDefinitions.definitions[index] = new NPCDefinitions(index, name, description, combatLevel, size, attackable, aggressive, retreats,
poisonous, respawnTime, maxHit, hitpoints, attackSpeed, attackAnim, defenceAnim, deathAnim, attackBonus, meleeDefence,
rangedDefence, magicDefence);
代码完美运行。
我对此感到困惑,我如何使用 ArrayList 来完成这项工作?
最佳答案
使用List#add
而不是List#get
并分配运算符。
尝试:
NPCDefinitions.definitions.add(index, new NPCDefinitions(index, name, description, combatLevel, size, attackable, aggressive, retreats,
poisonous, respawnTime, maxHit, hitpoints, attackSpeed, attackAnim, defenceAnim, deathAnim, attackBonus, meleeDefence,
rangedDefence, magicDefence));
编辑:
NPCDefinitions.definitions
使用前必须定义。
分配一个新的ArrayList
实例为definitions
喜欢 NPCDefinitions.definitions = new ArrayList<>();
类 NPCDefinitions
中成员定义之前或处的某处.
关于java - 左侧必须是变量(ArrayList 和 Array),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/31098964/