java - 与默认构造函数作斗争，隐式 super 构造函数未定义

Question

我有两个类(class)，一门称为“俱乐部”，一门称为“约会”。 - 日期延长俱乐部

当我在下面添加这段代码时:在 Clubs 类中，它会弄乱我的 Date 类以及所有扩展 Clubs 的其他类。

public Clubs(Parcel in) { readFromParcel(in); }

这是我的约会类(class)

public class Date extends Clubs {
    public Date(String day){
        clubName = day;
        date = "";
        eventType = "";     
    }
}

implicit super constructor Clubs() is undefined must explicitly invoke another constructor

上面的消息是当我将鼠标悬停在 public Date(String day){ 上的红色下划线时收到的错误

任何帮助将不胜感激:

下面我发布了俱乐部类(class)

public class Clubs implements Parcelable{   
        protected String clubName;
        protected String address;
        protected String postcode;
        protected String contactName;
        protected String contactPhone;
        String date, eventType, scrutTime, startTime, eventName, week;


        public Clubs(String e){

        }

        public String getDetails() {
            return address + " " + postcode + " " + contactName + " " + contactPhone + " " + date + " " + eventType + " " + scrutTime + " ";    
        }

        public String getEvent() {          
                return date + " " + eventType; 
        }       

        public String getName(){
            return clubName;
        }

        public String getDate(){
            return date;
        }

        public String getWeek(){
            return week;
        }

        public String geteventName(){
            return eventName;
        }

        public void setEvent(String eventType, String date, String scrutTime, String startTime, String eventName, String week) {
            this.eventType = eventType;
            this.date = date; 
            this.scrutTime = scrutTime;
            this.startTime = startTime;
            this.eventName = eventName;
            this.week = week;
        }

        public void setEvent(String eventType, String date) {
            this.eventType = eventType;
            this.date = date; 
        }

Answer 1

当你编写子类时，编译器会自动将对 super 构造函数(父类(super class)的构造函数)的调用插入到子类构造函数的第一行。但是，您的 Clubs 类没有默认构造函数(没有参数的构造函数)，并且编译器不知道使用哪个 String 参数来调用存在的构造函数，因此它会提示。

要解决您的问题，您必须在 Date 构造函数中添加以下内容作为第一行:

super("some string that makes sense in your case");