将元素添加到自定义类列表

Question

I have created a custom class:

package mypackage;

public class myClass {

    public int a;
    public int b;
    public int c;

    public myClass(int a, int b, int c){
        this.a = a;
        this.b = b;
        this.c = c;
    }
}

I then create an arraylist in another class file:

ArrayList<myClass > myArrayList= new ArrayList<myClass>();

But how do I add data to it? I want to do something like this:

for(int indexer = 0; indexer < count; indexer++){
    myArrayList[indexer].a = 5;
    myArrayList[indexer].b = 5;
    myArrayList[indexer].c = 5;
}

This obviously doesn't work. How is this suppose to work?

Answer 1

Look, your myArrayList is an ArrayList of myClass . So to add elements into myArrayList you need myCLass objects. (Offtopic: Please use capital letter for class naming, say MyClass instead of myClass ). For example,

myClass myClassObject = new myClass(5, 5, 5);

Now use add() to add myClassObject object into your ArrayList

myArrayList.add(myClassObject);

Answer 2

If you want to be able to access a,b,c variables you got to declare them like this

public static int a; public static int b; and so on. Another option is to create getters and setters:

private int a;

public int getA() {
    return a;
}

public void setA(int a) {
    this.a=a;
}

Otherwise, use the List add method myArrayList.add(...);