Android List(集合集合)中的对象以某一个字段排序案例中的对象以某一个字段排序案例
在Android开发中,有时我们需要对一个对象的集合按照某一个字段进行排序,
Bean
public class Student {
private int studentId;
private String studentName;
private int age;
public Student(int studentId , String studentName, int age){
this.studentId=studentId;
this.studentName=studentName;
this.age=age;
}
public int getStudentId() {
return studentId;
}
public void setStudentId(int studentId) {
this.studentId = studentId;
}
public String getStudentName() {
return studentName;
}
public void setStudentName(String studentName) {
this.studentName = studentName;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
实现排序实现排序
实现排序比较类 Comparator ,里面实现排序规则。
public class test {
/**
* @param args
*/
public static void main(String[] args) {
Student stu1 = new Student (1,"zhangsan",28);
Student stu2 = new Student (2,"zhagnsan",19);
Student stu3 = new Student (3,"wangwu",19);
Student stu4 = new Student (4,"wangwu",19);
Student stu5 = new Student (5,"zhaoliu",18);
ArrayList<Student> list = new ArrayList<Student>();
list.add(stu1);
list.add(stu2);
list.add(stu3);
list.add(stu4);
list.add(stu5);
//排序规则,这里是以年龄先排序,如果年龄相同
Comparator<Student> comparator = new Comparator<Student>() {
public int compare(Student s1, Student s2) {
// 先排年龄
if (s1.getAge() != s2.getAge()) {
return s1.getAge() - s2.getAge();
} else if (!s1.getStudentName().equals(s2.getStudentName())) {
// 年龄相同则按姓名排序
return s1.getStudentName().compareTo(s2.getStudentName());
} else {
// 姓名也相同则按学号排序
return s1.getStudentId() - s2.getStudentId();
}
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