Question

下午！我在“电视”课上遇到了布尔方法的问题。所有我基本上想要完成的是无论何时调用该方法，我都希望切换powerStatus的值。

/**
 * @author Thomas Samuel
 * @version 1.0
 * @since 22/02/2017
 * <h1>Television Remote / Lab Sheet 2</h1>
 * <p1>The following program is made for a television remote to control power, channel information, and volume.</p1>
*/
class Television {
    Television Television = new Television();
    boolean powerStatus = false;
    int currentChannel;
    int currentVolume = 50;
    boolean togglePower(boolean powerStatus) {
        if(powerStatus = false) {
            powerStatus = true;
        } else if(powerStatus = true) {
            powerStatus = false;
        }
        return powerStatus;
    }
    boolean getPowerStatus(boolean powerStatus) {
    return powerStatus;
    }
}
public class Controller {
    public static void main(String[] args) {
        Television.togglePower();
    }
}

我收到的错误如下：

Controller.java:27: error: method togglePower in class Television cannot be applied to given types;
        Television.togglePower();
                  ^
  required: boolean
  found: no arguments
  reason: actual and formal argument lists differ in length
1 error

Answer 1

您收到错误是因为您在没有参数的情况下调用togglePower，但此方法需要boolean参数。

将togglePower方法更改为不参数，因为它已拥有powerStatus变量：

    boolean togglePower() {

        powerStatus = !powerStatus;

        return powerStatus;
    }

以同样的方式，使用简单的getter方法获取参数是没有意义的，所以请尝试：

    boolean getPowerStatus() {
        return powerStatus;
    }

Answer 2

请仔细研究此代码以了解需要更改的内容

class Television {
    boolean powerStatus = false;
    int currentChannel;
    int currentVolume = 50;
    boolean togglePower() {
        powerStatus = !powerStatus;
        return powerStatus;
    }
    boolean getPowerStatus() {
        return powerStatus;
    }
}
public class Controller {
    public static void main(String[] args) {
        Television tv = new Television();
        tv.togglePower();
        System.out.println(tv.getPowerStatus());
    }
}

我将实例化移动到main方法中，并将togglePower更改为使用逻辑“not”来切换布尔值。

实际和正式方法列表的长度各不相同

2 个答案: