Question

我正在编写一组与抽象超类相关联的子类。有一个默认构造函数，但是当我创建另一个构造函数时，它会给我以下错误：

Implicit super constructor Event() is undefined. Must explicitly invoke another constructor

我的代码如下：

public class Meeting extends Event {

private String location;
private String subject;
private String notes;
private String attendeeName;

// Array of attendees as string
private String[] listofAttendees = new String[10];

public Meeting(Date dueDate, Date reminderDate, String location,
        String subject, String notes) {
    super(dueDate, reminderDate);
    this.location = location;
    this.subject = subject;
    this.notes = notes;

}

public Meeting(String attendeeName) {   // this is the error constructor 
    this.attendeeName = attendeeName;
}

public String getLocation() {
    return location;
}

public void setLocation(String location) {
    this.location = location;
}

public String getSubject() {
    return subject;
}

public void setSubject(String subject) {
    this.subject = subject;
}

public String getNotes() {
    return notes;
}

public void setNotes(String notes) {
    this.notes = notes;
}

public String[] addAttendee(String name) {
    // adding for loop for adding the list of attendees to the array
    for (int i = 0; i < listofAttendees.length; i++) {
        // array index(i) = name of attendee
        listofAttendees[i] = name;
    }

    return listofAttendees;
}

}

Answer 1

您正在扩展的对象Event没有不带参数的构造函数。所以你需要调用super并像在其他构造函数中那样指定参数。

Answer 2

在你的构造函数中：

public Meeting(String attendeeName) {
    this.attendeeName = attendeeName;
}

你并没有像在你的其他构造函数中那样明确地调用super。因此，Java隐式地尝试在基类上调用默认构造函数，即Event（）。您需要在Event中定义默认构造函数，或者需要在此构造函数中将一个显式调用添加到其中一个已定义的Event构造函数中。

隐式超级构造函数Event（）未定义

2 个答案: