Sorting an arraylist in Java language
I have an arraylist set up. I have input instuctions set up too, so that the user can enter one string, then one integer, then one string (the first name, the age, and the last name).
I need to sort the arraylist by the last name. The code I have entered so far is all under the main method:-
public static void main(String[] args) {
Name Name[] = new Name[50];
int co开发者_如何学JAVAunt = 0;
for (int i=0; i<50; i++)
NewName[i] = new Name();
//ADD NEW TO ARRAYLIST NAME
String FName = JOptionPane.showInputDialog("first name");
int age = Integer.parseInt(JOptionPane.showInputDialog("age"));
String LName = JOptionPane.showInputDialog("last name");
NewName[count] = new Name(FName, age, LName);
count = count++;
}
//ITEMS SORT BY LAST NAME
//CODE FOR SORT GOES HERE
Take a look at Comparable, Comparator, Arrays.sort and Collections.sort
import java.util.Arrays;
class Name implements Comparable<Name> {
private String lastName;
//Other fields
public Name(String lastName){
this.lastName = lastName;
}
public int compareTo(Name o) {
//Null checks etc
return lastName.compareTo(o.lastName);
}
public String getLastName(){
return lastName;
}
//Getter and setter methods
}
public class Test{
public static void main(String[] args) {
Name[] arr = new Name[]{new Name("AAC"), new Name("AAD"), new Name("AAA"),new Name("ABC"), new Name("AADDE")};
Arrays.sort(arr);
for(Name nm:arr){
System.out.println(nm.getLastName());
}
}
}
This isn't meant to be offensive but I would suggest you learn the basics before you move on to Swing.
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