java - 从另一个方法访问对象信息

Question

我有一个程序，但我不明白如何在另一种方法中访问一个特定对象的信息。这是我的程序的一个小样本，我想在同一个类(称为 Cyclist)中创建此方法骑手。我想打印出这里的骑手列表，但我不明白如何...

public void riders() {
    //System.out.print(c1.getName())
    //this does not work.
    //here I want to print out all the names of the riders, i.e. c1's name, c2's name... cn... 

}



public void abilities() {

    //Pardilla blir til!
    Cyclist c1 = new Cyclist();

    c1.setName("Sergio Pardilla");
    c1.setMountain(75);
    c1.setTimeTrial(60);
    c1.setSprint(60);
    c1.setAge(30);

    System.out.println(c1.getName() + "'s abilities:");
    System.out.println("Mountain - " + c1.getMountain());
    System.out.println("TimeTrial - " + c1.getTimeTrial());
    System.out.println("Sprint - " + c1.getSprint());
    System.out.println("Age - " +c1.getAge());

    }

Answer 1

您在 riders() 方法中看不到 c1 变量。c1在能力()内部声明，然后是它的本地变量，仅在内部可见。如果你想在这个方法之外使用变量，你应该使用一个字段而不是局部变量，或者将它作为参数传递给rider方法。

List<Cyclist> cyclists = new ArrayList<>(); // Declared as field

public void riders() {
    for (cyclist : cyclists){
      System.out.print(cyclist.getName())
    }
}



public void abilities() {

//Pardilla blir til!
Cyclist c1 = new Cyclist();

c1.setName("Sergio Pardilla");
c1.setMountain(75);
c1.setTimeTrial(60);
c1.setSprint(60);
c1.setAge(30);

System.out.println(c1.getName() + "'s abilities:");
System.out.println("Mountain - " + c1.getMountain());
System.out.println("TimeTrial - " + c1.getTimeTrial());
System.out.println("Sprint - " + c1.getSprint());
System.out.println("Age - " +c1.getAge());

cyclists.add(c1); //Add cyclist to cyclists list
}