我试图将选定的项目从JList（uniOptions）添加到ArrayList（studentChoices），然后传递给一个对象。问题是它只需要第一次选择两次，它应该进行3次选择然后再单独添加到ArrayList。
这是actionListener：
uniOptions.addListSelectionListener(new ListSelectionListener() {
int selectionsMade=0;
int[] selectionIndex;
public void valueChanged(ListSelectionEvent event) {
selectionIndex = uniOptions.getSelectedIndices();
if(event.getValueIsAdjusting()) {
selectionsMade++;
uniSelection = uniOptions.getSelectedValue();
System.out.println("Number of Selections made: " + selectionsMade);
System.out.println(selectionIndex.length); //shows item is selected
}
}
});
这是JButton的actionlistener。仅当输入有效时，按钮动作侦听器才会添加JList中的选定值并将其添加到ArrayList。
submit.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent getProfile){
boolean validInput = true;
//checks if average is an integer
try {
studentsAverage = Integer.parseInt(averagePromptTF.getText());
}catch (NumberFormatException e){
validInput = false;
System.out.println("please enter valid input");
}
//add student information and choices to student object
if (studentsAverage >75 && validInput && uniSelection != null && studentsAverage < 100) {
Student person = new Student (namePromptTF.getText(), averagePromptTF.getText(), uniSelection, studentChoices);
Applicants.add(person);
arrayCount++;
numberOfApplicants.setText(arrayCount +"/" +100+"students");
System.out.println(person.toString());
studentChoices.add(uniOptions.getSelectedValue());
for ( int i = 0; i< arrayCount; i++) {
studentChoices.add(uniOptions.getSelectedValue());
}
}else if (uniSelection == null | studentsAverage <75 | studentsAverage>100 | averagePromptTF == null) {
System.out.println("choose atleast 3 universities to apply");
System.out.println("Student average must be between 75 and 100");
}
System.out.println(studentChoices);
//clears input after submission
namePromptTF.setText(null);
averagePromptTF.setText(null);
uniOptions.clearSelection();
}
});
我得到的输出是
LastName, average= 95, Waterloo:
[Waterloo, Waterloo]
到目前为止，我写的代码只添加了2个选项，并重复添加所选的第一个。预期的输出应该是
Smith, average=87, York-admitted, McGill-rejected, UofT- rejected
这是上下文代码的其余部分，因为我不确定为什么它不能正常工作
import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import java.awt.*;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.EventObject;
import java.awt.event.*;
public class ApplicationCentre extends JFrame implements ActionListener {
private CardLayout CARD_MANAGER;
private JPanel MAIN_PAGE;
private JButton CONTROL[];
private String buttonNames[] = {"INPUT", "DISPLAY ALL", "SEARCH"};
private int arrayCount = 0;//KEEPS TRACK FO THE SIZE OF THE ARRAYLIST
private int studentsAverage; // HOLD STUDENT AVERAGE
private ArrayList<Student> Applicants = new ArrayList<Student>(); //CREATES ARRAY OF STUDENT OBJECTS
private String[] selectionList = {"York","Toronto", "Brock", "Guelph", "Waterloo", "McGill", "Concordia", "Laval", "Macmaster", "Western"};
private JList<String> uniOptions; // JLIST OF UNIVERSITY OPTIONS
ArrayList<String> studentChoices = new ArrayList<String>(); //ARRAYLIST OF OF STUDENT CHOICES
private String uniSelection;
ApplicationCentre (){
super("Application Centre");
this.getContentPane();
//>>CONFIGURE MAIN PAGE
MAIN_PAGE = new JPanel();
CARD_MANAGER = new CardLayout();
MAIN_PAGE.setLayout(CARD_MANAGER);
MAIN_PAGE.setPreferredSize(new Dimension(325, 500));
MAIN_PAGE.add(inputPanel());
MAIN_PAGE.add(displayAllPanel(), "Display All");
MAIN_PAGE.add(searchPanel());
//>>CREATE AND ADD BUTTONS TO CONTROL BOARD
JPanel CONTROL_BOARD = new JPanel();
CONTROL_BOARD.setLayout(new GridLayout (3, 0));
CONTROL = new JButton[buttonNames.length];
for(int i = 0; i<buttonNames.length;i++) {
CONTROL[i]=new JButton(buttonNames[i]);
CONTROL[i].addActionListener(this);
CONTROL_BOARD.add(CONTROL[i]);
}
//ADD MAIN_PAGE PANEL AND CONTROL_BOARD PANEL TO FRAME
this.add(MAIN_PAGE, BorderLayout.EAST);
this.add(CONTROL_BOARD, BorderLayout.WEST);
}
/***************************************************************///PANEL LAYOUT
JPanel inputPanel() {
JPanel input = new JPanel();
input.setLayout(new BoxLayout(input, BoxLayout.Y_AXIS));
/***********************************INPUT SUB-PANEL***/
JPanel namePanel = new JPanel();
JLabel namePrompt = new JLabel("Enter students name: ");
JTextField namePromptTF = new JTextField();
namePromptTF.setColumns(18);
namePromptTF.setEditable(true);
namePanel.add(namePrompt);
namePanel.add(namePromptTF);
/***********************************AVERAGE SUB-PANEL***/
JPanel averagePanel = new JPanel();
JLabel averagePrompt = new JLabel("Enter students average: ");
JTextField averagePromptTF = new JTextField();
averagePromptTF.setColumns(18);
averagePromptTF.setEditable(true);
averagePanel.add(averagePrompt);
averagePanel.add(averagePromptTF);
/***********************************UNIVERSITY SELECTOR SUB-PANEL***/
JPanel UniversitySelectorPanel = new JPanel();
JLabel uniSelector = new JLabel("Please select 3 Universitys to apply to: ");
uniOptions.setFixedCellWidth(250);
uniOptions.setFixedCellHeight(20);
uniOptions.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
uniOptions.addListSelectionListener(new ListSelectionListener() {
int selectionsMade=0;
int[] selectionIndex;
public void valueChanged(ListSelectionEvent event) {
selectionIndex = uniOptions.getSelectedIndices();
if(event.getValueIsAdjusting()) {
selectionsMade++;
uniSelection = uniOptions.getSelectedValue();
System.out.println("Number of Selections made: " + selectionsMade);
System.out.println(selectionIndex.length);
}
}
});
UniversitySelectorPanel.add(uniSelector);
UniversitySelectorPanel.add(uniOptions);
/*****************************************/ //SUBMIT BUTTON
JPanel bottomPanel = new JPanel(new BorderLayout());
JLabel numberOfApplicants = new JLabel("No Students have applied");
JButton submit = new JButton("Submit");
/*********JBUTTON FUNCTIONALITY*****************/
submit.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent getProfile){
boolean validInput = true;
//checks if average is an integer
try {
studentsAverage = Integer.parseInt(averagePromptTF.getText());
}catch (NumberFormatException e){
validInput = false;
System.out.println("please enter valid input");
}
//add student information and choices to student object
if (studentsAverage >75 && validInput && uniSelection != null && studentsAverage < 100) {
Student person = new Student (namePromptTF.getText(), averagePromptTF.getText(), uniSelection, studentChoices);
Applicants.add(person);
arrayCount++;
numberOfApplicants.setText(arrayCount +"/" +100+"students");
System.out.println(person.toString());
studentChoices.add(uniOptions.getSelectedValue());
for ( int i = 0; i< arrayCount; i++) {
studentChoices.add(uniOptions.getSelectedValue());
}
}else if (uniSelection == null | studentsAverage <75 | studentsAverage>100 | averagePromptTF == null) {
System.out.println("choose atleast 3 universities to apply");
System.out.println("Student average must be between 75 and 100");
}
System.out.println(studentChoices);
//clears input after submission
namePromptTF.setText(null);
averagePromptTF.setText(null);
uniOptions.clearSelection();
}
});
bottomPanel.add(submit);
input.add(namePanel);
input.add(averagePanel);
input.add(UniversitySelectorPanel);
input.add(submit);
input.add(numberOfApplicants);
return input;
}
/*******************************************END OF INPUT PANEL*/
///////////////////////////DISPLAY PANEL//////////////////////////
JPanel displayAllPanel() {
JPanel displayAll = new JPanel();
displayAll.setLayout(new BorderLayout());
JLabel card2Title = new JLabel("DISPLAY ALL APPLICANTS");
JTextArea displayAllApplicants = new JTextArea();
/************************APPLICANT DISPLAY SUB PANEL*/
JPanel applicantDisplayPanel = new JPanel();
applicantDisplayPanel.setMinimumSize(displayAllApplicants.getPreferredSize());
displayAllApplicants.setPreferredSize(new Dimension(275, 450));
displayAllApplicants.setEditable(false);
displayAllApplicants.setVisible(true);
applicantDisplayPanel.add(card2Title);
applicantDisplayPanel.add(displayAllApplicants);
displayAll.add(applicantDisplayPanel, BorderLayout.CENTER);
/**********************************************************/
return displayAll;
}
/**********************************************************END OF DISPLAY PANEL */
///////////////////////////SEARCH PANEL//////////////////////////
JPanel searchPanel() {
JLabel card3title = new JLabel("SEARCH");
JPanel searchPanel = new JPanel();
searchPanel.setLayout(new BoxLayout(searchPanel, BoxLayout.Y_AXIS));
JPanel searchDisplayPanel = new JPanel();
JTextArea searchTextArea = new JTextArea();
searchTextArea.setMinimumSize(searchTextArea.getPreferredSize());
searchTextArea.setPreferredSize(new Dimension(275, 450));
searchTextArea.setEditable(false);
searchTextArea.setVisible(true);
searchDisplayPanel.add(searchTextArea);
searchPanel.add(card3title);
searchPanel.add(searchDisplayPanel);
return searchPanel;
}
/**********************************************************END OF DISPLAY PALNEL */
/**********************************************************************************************/
//ACTION LISTENER FOR CARDLAYOUT OPTIONS
public void actionPerformed(ActionEvent e) {
if(e.getSource() == CONTROL[0]) {
CARD_MANAGER.first(MAIN_PAGE);
}else if(e.getSource()==CONTROL[1]) {
CARD_MANAGER.show(MAIN_PAGE, "Display All");
}else if (e.getSource() == CONTROL[2]) {
CARD_MANAGER.last(MAIN_PAGE);
}
}
/**********************************************************************/ //DRIVER METHOD
public static void main(String[] args) {
ApplicationCentre frame = new ApplicationCentre();
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setSize(700, 500);
frame.pack();
frame.setVisible(true);
}
}
class Student {
private String FAMILYNAME;
private String AVERAGE;
private String OPTION1;
private String OPTION2;
private String OPTION3;
private ArrayList<String> CHOICES = new ArrayList();
Student (String lastName, String avrg, String Op1, ArrayList<String> hello){
FAMILYNAME = lastName;
AVERAGE = avrg;
OPTION1 = Op1;
CHOICES = hello;
}
/********************************************************/
public String toString() {
return FAMILYNAME+", " + "average= " + AVERAGE + ", "+ OPTION1 + ": " + "\n";
}
}