Android常见设计模式：什么是命令模式？

// Command: 命令接口
interface Command {
    void execute();
}

// Receiver: 接收者类，实际执行命令的逻辑
class Light {
    public void turnOn() {
        System.out.println("灯已打开");
    }

    public void turnOff() {
        System.out.println("灯已关闭");
    }
}

// ConcreteCommand: 具体命令类，用于打开灯
class TurnOnLightCommand implements Command {
    private Light light;

    public TurnOnLightCommand(Light light) {
        this.light = light;
    }

    @Override
    public void execute() {
        light.turnOn();
    }
}

// ConcreteCommand: 具体命令类，用于关闭灯
class TurnOffLightCommand implements Command {
    private Light light;

    public TurnOffLightCommand(Light light) {
        this.light = light;
    }

    @Override
    public void execute() {
        light.turnOff();
    }
}

// Invoker: 调用者，持有命令并触发执行
class RemoteControl {
    private Command command;

    public void setCommand(Command command) {
        this.command = command;
    }

    public void pressButton() {
        command.execute();
    }
}

// Client: 客户端，负责组装命令、接收者和调用者
public class CommandPatternDemo {
    public static void main(String[] args) {
        Light livingRoomLight = new Light();

        // 创建命令
        Command turnOn = new TurnOnLightCommand(livingRoomLight);
        Command turnOff = new TurnOffLightCommand(livingRoomLight);

        // 配置调用者
        RemoteControl remote = new RemoteControl();

        // 打开灯
        remote.setCommand(turnOn);
        remote.pressButton();

        // 关闭灯
        remote.setCommand(turnOff);
        remote.pressButton();
    }
}