Java JList(与arraylist链接)添加元素会导致内存过高或不可用
对不起,我的英语不好。我一直在努力解决一个应用程序中遇到的问题,这个应用程序使用JavaSwing库作为GUI 我会解释一个更简单的问题,让你明白(如果我发布应用程序的源代码,会更难理解,因为我对每个组件使用不同的类等等) 我使用JList来显示人员的arraylist。请看下面的代码:Java JList(与arraylist链接)添加元素会导致内存过高或不可用,java,swing,memory,components,jlist,Java,Swing,Memory,Components,Jlist,对不起,我的英语不好。我一直在努力解决一个应用程序中遇到的问题,这个应用程序使用JavaSwing库作为GUI 我会解释一个更简单的问题,让你明白(如果我发布应用程序的源代码,会更难理解,因为我对每个组件使用不同的类等等) 我使用JList来显示人员的arraylist。请看下面的代码: import java.awt.BorderLayout; import java.awt.Component; import java.awt.EventQueue; import java.awt.even
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import javax.swing.AbstractListModel;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.ListCellRenderer;
public class Test {
private JFrame frame;
private ArrayList<Person> persons = new ArrayList<>();
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Test window = new Test();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public Test() {
initialize();
}
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(new BorderLayout());
for (int i = 0; i < 111111; i++) {
Person p = new Person(i);
persons.add(p);
}
PersonList pl = new PersonList(persons);
JScrollPane sp = new JScrollPane(pl);
frame.getContentPane().add(sp, BorderLayout.CENTER);
JButton addPerson = new JButton("add person");
addPerson.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
Person p = new Person(166);
/*
* This will make the list dissapear.
*/
// persons.add(p);
// pl.repaint();
// pl.revalidate();
/*
* This will cause high memory usage on each button click.
*/
jlist.Test.PersonList.PersonModel m = (jlist.Test.PersonList.PersonModel) pl.getModel();
m.add(p);
}
});
frame.getContentPane().add(addPerson, BorderLayout.PAGE_END);
}
@SuppressWarnings("serial")
private class PersonList extends JList<Person> {
private ArrayList<Person> listPersons;
public PersonList(ArrayList<Person> persons) {
this.listPersons = persons;
setModel(new PersonModel());
setCellRenderer(new PersonRenderer());
}
private class PersonRenderer extends JTextField implements ListCellRenderer<Person> {
@Override
public Component getListCellRendererComponent(JList<? extends Person> list, Person value, int index,
boolean isSelected, boolean cellHasFocus) {
setText("height: " + value.getHeight());
return this;
}
}
private class PersonModel extends AbstractListModel<Person> {
public void add(Person p) {
listPersons.add(p);
fireContentsChanged(this, listPersons.size(), listPersons.size() - 1);
}
@Override
public Person getElementAt(int arg0) {
return listPersons.get(arg0);
}
@Override
public int getSize() {
return listPersons.size();
}
}
}
private class Person {
private int height;
public Person(int height) {
this.setHeight(height);
}
@SuppressWarnings("unused")
public int getHeight() {
return height;
}
public void setHeight(int height) {
this.height = height;
}
}
}
导入java.awt.BorderLayout;
导入java.awt.Component;
导入java.awt.EventQueue;
导入java.awt.event.ActionEvent;
导入java.awt.event.ActionListener;
导入java.util.ArrayList;
导入javax.swing.AbstractListModel;
导入javax.swing.DefaultListModel;
导入javax.swing.JButton;
导入javax.swing.JFrame;
导入javax.swing.JList;
导入javax.swing.JScrollPane;
导入javax.swing.JTextField;
导入javax.swing.ListCellRenderer;
公开课考试{
私有JFrame;
private ArrayList persons=新ArrayList();
公共静态void main(字符串[]args){
invokeLater(新的Runnable(){
公开募捐{
试一试{
测试窗口=新测试();
window.frame.setVisible(true);
}捕获(例外e){
e、 printStackTrace();
}
}
});
}
公开考试(){
初始化();
}
私有void初始化(){
frame=新的JFrame();
机架立根(100450300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(新的BorderLayout());
对于(int i=0;i<111111;i++){
人员p=新人员(i);
增加(p);
}
PersonList pl=新的PersonList(个人);
JScrollPane sp=新的JScrollPane(pl);
frame.getContentPane().add(sp,BorderLayout.CENTER);
JButton addPerson=新JButton(“addPerson”);
addPerson.addActionListener(新的ActionListener(){
@凌驾
已执行的公共无效操作(操作事件e){
人员p=新人员(166);
/*
*这将使该列表不复存在。
*/
//增加(p);
//pl.重新绘制();
//pl.重新验证();
/*
*这将导致每次单击按钮时内存占用率高。
*/
jlist.Test.PersonList.PersonModel m=(jlist.Test.PersonList.PersonModel)pl.getModel();
m、 加(p);
}
});
frame.getContentPane().add(addPerson,BorderLayout.PAGE_END);
}
@抑制警告(“串行”)
私有类PersonList扩展了JList{
私人ArrayList上市公司;
公共人员列表(ArrayList人员){
这个.listPersons=人;
setModel(newpersonmodel());
setCellRenderer(新PersonRenderer());
}
私有类PersonRenderer扩展JTextField实现ListCellRenderer{
@凌驾
公共组件GetListCellRenderComponent(JList您看起来有点过于复杂了。首先,我不会使用JTextField作为渲染器,而是使用DefaultListCellRenderer,如果需要的话会添加边框。我还建议不要扩展JList,而是更简单地使用一个。如果需要,您可以扩展模型,或者更简单地使用DefaultListCell型号
例如:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.event.ActionEvent;
import javax.swing.*;
@SuppressWarnings("serial")
public class Test2 extends JPanel {
private static final int MAX_PERSONS = 111111;
private DefaultListModel<Person> personModel = new DefaultListModel<>();
private JList<Person> personJList = new JList<>(personModel);
public Test2() {
personJList.setPrototypeCellValue(new Person(11111111));
personJList.setCellRenderer(new PersonRenderer());
personJList.setVisibleRowCount(12);
JScrollPane scrollPane = new JScrollPane(personJList);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
for (int i = 0; i < MAX_PERSONS; i++) {
personModel.addElement(new Person(i));
}
setLayout(new BorderLayout());
add(scrollPane);
add(new JButton(new AddPersonAction()), BorderLayout.PAGE_END);
}
private class AddPersonAction extends AbstractAction {
public AddPersonAction() {
super("Add Person");
}
@Override
public void actionPerformed(ActionEvent arg0) {
Person p = new Person(166);
personModel.addElement(p);
}
}
private class PersonRenderer extends DefaultListCellRenderer {
@Override
public Component getListCellRendererComponent(JList<?> list, Object value, int index,
boolean isSelected, boolean cellHasFocus) {
if (value != null) {
value = ((Person) value).getHeight();
} else {
value = "";
}
JComponent renderer = (JComponent) super.getListCellRendererComponent(list, value,
index, isSelected, cellHasFocus);
// if you want a border around your renderer:
renderer.setBorder(BorderFactory.createLineBorder(Color.BLACK));
return renderer;
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
private static void createAndShowGui() {
Test2 mainPanel = new Test2();
JFrame frame = new JFrame("Test2");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
public class Person {
private int height;
public Person(int height) {
this.setHeight(height);
}
@SuppressWarnings("unused")
public int getHeight() {
return height;
}
public void setHeight(int height) {
this.height = height;
}
}