Unity 命令模式（实例详解）

文章目录

- - 示例1：基础命令类结构
  - 示例2：旋转对象命令
  - 示例3：增加道具命令
  - 示例4：切换场景命令
  - 示例5：播放音效命令

在Unity中使用命令模式（Command Pattern）是一种常见的设计模式，用于实现对游戏或应用中一系列动作的记录、撤销和重做操作。下面通过五个简化的C#代码示例来详细说明命令模式在Unity中的应用：

示例1：基础命令类结构

// 基础命令接口
public interface ICommand
{void Execute();void Undo();
}// 具体命令类 - 例如移动角色命令
public class MoveCharacterCommand : ICommand
{private readonly Transform _character;private Vector3 _previousPosition;public MoveCharacterCommand(Transform character, Vector3 newPosition){_character = character;_previousPosition = character.position;}public void Execute(){_character.position = newPosition; // 假设newPosition是目标位置}public void Undo(){_character.position = _previousPosition;}
}// 命令管理器类，负责执行和回滚命令
public class CommandManager
{private List<ICommand> _commandHistory = new List<ICommand>();public void ExecuteCommand(ICommand command){command.Execute();_commandHistory.Add(command);}public void UndoLastCommand(){if (_commandHistory.Count > 0){var lastCommand = _commandHistory[_commandHistory.Count - 1];lastCommand.Undo();_commandHistory.RemoveAt(_commandHistory.Count - 1);}}
}

示例2：旋转对象命令

public class RotateObjectCommand : ICommand
{private readonly Transform _target;private Quaternion _originalRotation;public RotateObjectCommand(Transform target, Quaternion newRotation){_target = target;_originalRotation = target.rotation;}public void Execute(){_target.rotation = newRotation;}public void Undo(){_target.rotation = _originalRotation;}
}// 使用：
var rotateCmd = new RotateObjectCommand(someGameObject.transform, Quaternion.Euler(0, 90, 0));
commandManager.ExecuteCommand(rotateCmd);

示例3：增加道具命令

public class AddInventoryItemCommand : ICommand
{private readonly PlayerInventory _inventory;private readonly Item _itemToAdd;private bool _wasAdded;public AddInventoryItemCommand(PlayerInventory inventory, Item item){_inventory = inventory;_itemToAdd = item;}public void Execute(){_wasAdded = _inventory.AddItem(_itemToAdd);}public void Undo(){if (_wasAdded){_inventory.RemoveItem(_itemToAdd);}}
}// 使用：
var addItemCmd = new AddInventoryItemCommand(player.Inventory, newItem);
commandManager.ExecuteCommand(addItemCmd);

示例4：切换场景命令

public class ChangeSceneCommand : ICommand
{private readonly string _sceneName;private readonly Scene _previousScene;public ChangeSceneCommand(Scene currentScene, string newSceneName){_sceneName = newSceneName;_previousScene = currentScene;}public void Execute(){SceneManager.LoadScene(_sceneName);}public void Undo(){SceneManager.LoadScene(_previousScene.name);}
}// 使用（假设有一个SceneManager实例提供加载场景的方法）
var changeSceneCmd = new ChangeSceneCommand(SceneManager.GetActiveScene(), "NextScene");
commandManager.ExecuteCommand(changeSceneCmd);

示例5：播放音效命令

public class PlaySoundCommand : ICommand
{private readonly AudioSource _audioSource;private AudioClip _previousClip;private float _previousTime;public PlaySoundCommand(AudioSource audioSource, AudioClip clipToPlay){_audioSource = audioSource;if (_audioSource.isPlaying){_previousClip = _audioSource.clip;_previousTime = _audioSource.time;}}public void Execute(){_audioSource.clip = clipToPlay;_audioSource.Play();}public void Undo(){if (_previousClip != null){_audioSource.clip = _previousClip;_audioSource.time = _previousTime;if (_audioSource.isPlaying){_audioSource.Pause();}}}
}// 使用：
var playSoundCmd = new PlaySoundCommand(someAudioSource, newSoundClip);
commandManager.ExecuteCommand(playSoundCmd);