Android Java List 排序

原文章转自网上blog，但是其中代码运行后原来的list排序根本没有改变。

于是打开Comparator文档看了，发现原代码的compare函数实现的返回值有问题！

修正后运行结果正确了，代码如下：

@SuppressWarnings("unchecked")
void test() {
    ArrayList list = new ArrayList();
    list.add(new Person("lcl 28", 28));
    list.add(new Person("fx 23", 23));
    list.add(new Person("wqx 29", 29));
    list.add(new Person("qd 20", 20));
    list.add(new Person("xgw 69", 69));
    Comparator comp = new Comparator() {
        public int compare(Object o1, Object o2) {
            Person p1 = (Person) o1;
            Person p2 = (Person) o2;
            if (p1.age < p2.age)
                return -1;
            else if (p1.age == p2.age)
                return 0;
            else if (p1.age > p2.age)
                return 1;
            return 0;
        }
    };
    Collections.sort(list, comp);

    for (int i = 0; i < list.size(); i++) {
        Person p = (Person) list.get(i);
        System.out.println(p.getName());
    }
}

public static class Person {

    private int age;
    private String name;

    public Person(String name, int age) {
        this.age = age;
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
} www.zzzyk.com
@SuppressWarnings("unchecked")
void test() {
  ArrayList list = new ArrayList();
  list.add(new Person("lcl 28", 28));
  list.add(new Person("fx 23", 23));
  list.add(new Person("wqx 29", 29));
  list.add(new Person("qd 20", 20));
  list.add(new Person("xgw 69", 69));
  Comparator comp = new Comparator() {
   public int compare(Object o1, Object o2) {
    Person p1 = (Person) o1;
    Person p2 = (Person) o2;
    if (p1.age < p2.age)
     return -1;
    else if (p1.age == p2.age)
     return 0;
    else if (p1.age > p2.age)
     return 1;
    return 0;
   }
  };
  Collections.sort(list, comp);

  for (int i = 0; i < list.size(); i++) {
   Person p = (Person) list.get(i);
   System.out.println(p.getName());
  }
}

public static class Person {

private int age;
private String name;

  public Person(String name, int age) {
   this.age = age;
   this.name = name;
  }

  public int getAge() {
   return age;
  }

  public void setAge(int age) {
   this.age = age;
  }

  public String getName() {
   return name;
  }

  public void setName(String name) {
   this.name = name;
  }
}

摘自 michaelpp的专栏

补充：移动开发 , Android ,