我如何实现toString？

Question

如何在代码中使用toString方法？我想开启或关闭打印。我在哪里实现toString？

公共类SmartDevice扩展设备{布尔成员；

public SmartDevice(){

}

@Override
public void on() {
    if(member) System.out.println("On");
    else{
        member = true;
        System.out.println("Switched On");
    }
}

@Override
public void off() {
    if(!member) System.out.println("Off");
    else{
        member = false;
        System.out.println("Switched Off");
    }
}

}

主要类别：

    //initial state of devices
    System.out.println("Smart Device 1 switched on " + smartDevice1);
    System.out.println("Smart Device 2 switched on " + smartDevice2);
    System.out.println("Traditional Light Bulb switched on " + traditionalLightBulb1);
    System.out.println("Traditional Light Bulb switched on " + traditionalLightBulb2);

}

Answer 1

实现此目标的一种方法是为可以切换的状态添加一个变量

private String state = "";

然后覆盖默认的toString（）方法

@Override
public String toString() {
    return state;
}