Android Kotlin继承

1 子类采用主构造函数

//Person.ktpackage com.example.xhelloimport android.app.Personopen class Person {    var name = ""    var age = 0    fun eat() {        println(name + "is eating. He is + " + age + "years old.")    }}

//Student.ktimport android.app.Personclass Student(val sno: String, val grade: Int) : com.example.xhello.Person() {}

//learnKotlin.kt    val student = Student("a123", 5)    println("student grade is" + student.grade)    println("student son is" + student.sno)    student.eat()

运行结果如图所示:
Android Kotlin继承_第1张图片

2 子类采用主构造函数

//Person.ktpackage com.example.xhelloimport android.app.Personopen class Person (val name: String, val age: Int){}

//Student.ktpackage com.example.xhelloimport android.app.Personclass Student(val sno: String, val grade: Int, name:String, age: Int) :    com.example.xhello.Person(name, age) {    init {        println("Sno is " + sno)        println("grade is " + grade )    }}

Android Kotlin继承_第2张图片
3 子类中既有主构造函数也有次构造函数

//Person.ktpackage com.example.xhelloimport android.app.Personopen class Person (val name: String, val age: Int){}

//Student.ktpackage com.example.xhelloimport android.app.Personclass Student(val sno: String, val grade: Int, name:String, age: Int) :        com.example.xhello.Person(name, age) {    constructor(name: String, age: Int) : this("", 0, name, age){    }    constructor() : this("", 0){    }}

Android Kotlin继承_第3张图片
4 子类中只含有此构造函数

//Person.ktpackage com.example.xhelloimport android.app.Personopen class Person (val name: String, val age: Int){}

//Student.ktpackage com.example.xhelloimport android.app.Personclass Student : com.example.xhello.Person {    constructor(name: String, age: Int) : super(name, age){    }}

Android Kotlin继承_第4张图片

更多相关文章

随机推荐