Question

我想创建一个像＆＃34; android.view.View＆＃34;这样的类，它将显示＆＃34;＆＃39; android.view.View＆＃39中没有可用的默认构造函数;＆＃34;错误，如果在课堂上没有调用super（...）来扩展我的课程，抱歉我的英语不好，有没有人可以帮助我？感谢

- 修改

@Eran，谢谢，你的评论给了我一个提示，所以罪魁祸首是龙目岛注释＆＃34; @Data＆＃34;，即使我用参数创建一个构造函数也没有错误，任何想法如何实现这一点Lombok的？

Answer 1

您可以将其设为私有，以便其他类无法使用它。

public class MyClass{
    private String text;
    private int number;

    private MyClass(){
        this.text="hi";
    }

    public MyClass(int number){
        this();
        this.number = number
    }
    ...
}

这样，子类应该使用非默认构造函数：

public MyChildClass1 extends MyClass{
    //NO COMPILE: No default constructor available in MyClass
}

public MyChildClass2 extends MyClass{
    public MyChildClass2(){
        //NO COMPILE: No default constructor available in MyClass
    }
}

public MyChildClass3 extends MyClass{
    public MyChildClass3(){
        super(); //NO COMPILE: MyClass() has private access
    }
}

public MyChildClass4 extends MyClass{
    public MyChildClass4(){
        super(2); //It Works! (it will initialize number=2 and text="hi")
    }
}

Answer 2

这是您的主要班级模式。

public class MyParentClass {

    MyParentClass(int value) {

    }
}

如果任何类想要在不调用super(value)的情况下扩展它，将获得“parent_class_name中没有可用的默认构造函数”

如下所示：

public class ChildClass extends MyParentClass {

}

Answer 3

我只提供私有构造函数：

20160711,"M","N1","F","S","A","good data with.....some special character and space 
space ..
....","M","072","00126"

20160711,"M","N1","F","S","A","R","M","072","00126"
20160711,"M","N1","F","S","A","R","M","072","00126"

如何创建没有默认构造函数的类

3 个答案: