1.创建一个kotlin类A

class A  constructor(a:String,b:String){
    var name ="";
    var age="";
    init {
        name = a;
        age = b;
    }
}

2.创建一个集合

    var  list = ArrayList<A>();
 var  list = ArrayList<A>();
        list.clear()
        var  a = A("张三","18");
        var  b = A("李四","20");
        var  c = A("王五","25");
        list.add(a);
        list.add(b)
        list.add(c)

3.遍历一个集合

  for(a in list){//类似于java中的foreach
            Toast.makeText(this,a.name,Toast.LENGTH_LONG).show()
        }