Java 为什么我的线程在Swing中不能正常工作?
我正在使用simple for循环打印简单值以附加Java 为什么我的线程在Swing中不能正常工作?,java,multithreading,swing,event-dispatch-thread,Java,Multithreading,Swing,Event Dispatch Thread,我正在使用simple for循环打印简单值以附加JTextArea,当我运行它时,如果我在控制台输出中打印值,它将正常运行 但是,如果我在文本区域中附加JTextArea和打印值,它们都会在整个程序运行后附加 public class SwingThread { private JFrame frame; /** * Launch the application. */ public static void main(String[] args) { EventQueue.in
JTextArea
,当我运行它时,如果我在控制台输出中打印值,它将正常运行
但是,如果我在文本区域中附加JTextArea
和打印值,它们都会在整个程序运行后附加
public class SwingThread {
private JFrame frame;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
SwingThread window = new SwingThread();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public SwingThread() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JScrollPane scrollPane = new JScrollPane();
frame.getContentPane().add(scrollPane, BorderLayout.CENTER);
JTextArea textArea = new JTextArea();
scrollPane.setViewportView(textArea);
JButton btnNewButton = new JButton("New button");
scrollPane.setColumnHeaderView(btnNewButton);
btnNewButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent arg0)
{
try
{
for(int i = 0 ; i <= 5 ; i++)
{
textArea.append("Value "+i+"\n");
System.out.println("Value is" + i);
Thread.sleep(1000);
}
}
catch(Exception e)
{
System.out.println("Error : "+e);
}
}
});
}
}
公共类SwingThread{
私有JFrame;
/**
*启动应用程序。
*/
公共静态void main(字符串[]args){
invokeLater(新的Runnable(){
公开募捐{
试一试{
SwingThread窗口=新建SwingThread();
window.frame.setVisible(true);
}捕获(例外e){
e、 printStackTrace();
}
}
});
}
/**
*创建应用程序。
*/
公共SwingThread(){
初始化();
}
/**
*初始化框架的内容。
*/
私有void初始化(){
frame=新的JFrame();
机架立根(100450300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JScrollPane scrollPane=新的JScrollPane();
frame.getContentPane().add(滚动窗格,BorderLayout.CENTER);
JTextArea textArea=新的JTextArea();
scrollPane.setViewportView(文本区域);
JButton btnNewButton=新JButton(“新按钮”);
scrollPane.setColumnHeaderView(btnNewButton);
addActionListener(新ActionListener()
{
已执行的公共无效操作(操作事件arg0)
{
尝试
{
对于(int i=0;i您的问题在于使用Thread.sleep
,因为当您在执行时在Swing事件线程(或事件调度线程的EDT)上调用此函数时,它将使整个Swing事件线程处于睡眠状态。当这种情况发生时,无法执行此线程的操作,包括绘制GUI(更新GUI)并与用户交互,这将完全冻结您的GUI——不好。当前情况下的解决方案是将a用作伪循环。计时器在后台线程中创建一个循环,并保证其actionPerformed方法中的所有代码都将在Swing事件线程上调用,这是必要的,因为我们不需要want以附加到此线程之外的JTextArea
另外,正如其他人所指出的,如果您只想在Swing中延迟执行重复操作,那么可以使用此Swing计时器。另一方面,如果您希望在Swing中运行一段长时间运行的代码,那么此代码将再次阻止EDT并冻结您的程序。对于这种情况,请使用后台线程,例如SwingWorker。请查看更多关于此的信息
e、 g
整件事:
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.*;
import javax.swing.*;
public class SwingThread2 {
protected static final int MAX_VALUE = 5; // our constant
private JFrame frame;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
SwingThread2 window = new SwingThread2();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public SwingThread2() {
initialize();
}
private void initialize() {
frame = new JFrame();
// frame.setBounds(100, 100, 450, 300); // avoid this
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JScrollPane scrollPane = new JScrollPane();
frame.getContentPane().add(scrollPane, BorderLayout.CENTER);
JTextArea textArea = new JTextArea(15, 40);
scrollPane.setViewportView(textArea);
JButton btnNewButton = new JButton("New button");
scrollPane.setColumnHeaderView(btnNewButton);
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
// delay between timer ticks: 1000
int timerDelay = 1000;
new Timer(timerDelay, new ActionListener() {
private int counter = 0;
@Override
public void actionPerformed(ActionEvent e) {
// timer's stopping condition
if (counter >= MAX_VALUE) { // MAX_VALUE is a constant int = 5
((Timer) e.getSource()).stop();
} else {
textArea.append("Value " + counter + "\n");
}
counter++; // increment timer's counter variable
}
}).start();
}
});
// better to avoid setting sizes but instead to
// let the components size themselves vis pack
frame.pack();
frame.setLocationRelativeTo(null);
}
}
为了进一步了解,这里有一个例子,上面的程序使用SwingWorker执行长时间运行的操作,然后使用此操作更新JProgressBar。worker非常简单,只需使用while循环将计数器变量提前一个有界的随机量。然后,它使用此值来更新其own progress属性(一个只能从0到100的值,因此在其他情况下,需要对该值进行规范化以符合此要求).I将PropertyChangeListener附加到worker,并且每当worker的进度值更改时,以及每当SwingWorker更改状态时(例如,当它完成操作时),都会在Swing事件线程上通知这一点。在后一种情况下,worker的StateValue变为StateValue.done。然后,侦听器更新G如果有任何问题,请询问
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.*;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.Random;
import java.util.concurrent.ExecutionException;
import javax.swing.*;
public class SwingThread2 {
protected static final int MAX_VALUE = 5; // our constant
private JFrame frame;
private JProgressBar progressBar = new JProgressBar();
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
SwingThread2 window = new SwingThread2();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public SwingThread2() {
initialize();
}
private void initialize() {
frame = new JFrame();
// frame.setBounds(100, 100, 450, 300); // avoid this
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JScrollPane scrollPane = new JScrollPane();
frame.getContentPane().add(scrollPane, BorderLayout.CENTER);
JTextArea textArea = new JTextArea(15, 40);
scrollPane.setViewportView(textArea);
JButton btnNewButton = new JButton("New button");
scrollPane.setColumnHeaderView(btnNewButton);
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
// delay between timer ticks: 1000
int timerDelay = 1000;
new Timer(timerDelay, new ActionListener() {
private int counter = 0;
@Override
public void actionPerformed(ActionEvent e) {
// timer's stopping condition
if (counter >= MAX_VALUE) { // MAX_VALUE is a constant
// int = 5
((Timer) e.getSource()).stop();
} else {
textArea.append("Value " + counter + "\n");
}
counter++; // increment timer's counter variable
}
}).start();
}
});
progressBar.setStringPainted(true);
JPanel bottomPanel = new JPanel();
bottomPanel.setLayout(new BoxLayout(bottomPanel, BoxLayout.LINE_AXIS));
bottomPanel.add(new JButton(new MyAction("Press Me")));
bottomPanel.add(progressBar);
frame.getContentPane().add(bottomPanel, BorderLayout.PAGE_END);
// better to avoid setting sizes but instead to
// let the components size themselves vis pack
frame.pack();
frame.setLocationRelativeTo(null);
}
private class MyAction extends AbstractAction {
public MyAction(String name) {
super(name);
int mnemonic = (int) name.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
}
public void actionPerformed(ActionEvent e) {
progressBar.setValue(0);
setEnabled(false);
MyWorker myWorker = new MyWorker();
myWorker.addPropertyChangeListener(new WorkerListener(this));
myWorker.execute();
}
}
private class WorkerListener implements PropertyChangeListener {
private Action action;
public WorkerListener(Action myAction) {
this.action = myAction;
}
@Override
public void propertyChange(PropertyChangeEvent evt) {
if ("progress".equals(evt.getPropertyName())) {
int progress = (int) evt.getNewValue();
progressBar.setValue(progress);
} else if ("state".equals(evt.getPropertyName())) {
if (evt.getNewValue() == SwingWorker.StateValue.DONE) {
action.setEnabled(true);
@SuppressWarnings("rawtypes")
SwingWorker worker = (SwingWorker) evt.getSource();
try {
// always want to call get to trap and act on
// any exceptions that the worker might cause
// do this even though get returns nothing
worker.get();
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
}
}
}
}
}
private class MyWorker extends SwingWorker<Void, Void> {
private static final int MULTIPLIER = 80;
private int counter = 0;
private Random random = new Random();
@Override
protected Void doInBackground() throws Exception {
while (counter < 100) {
int increment = random.nextInt(10);
Thread.sleep(increment * MULTIPLIER);
counter += increment;
counter = Math.min(counter, 100);
setProgress(counter);
}
return null;
}
}
}
导入java.awt.BorderLayout;
导入java.awt.EventQueue;
导入java.awt.event.*;
导入java.beans.PropertyChangeEvent;
导入java.beans.PropertyChangeListener;
导入java.util.Random;
导入java.util.concurrent.ExecutionException;
导入javax.swing.*;
公共类SwingThread2{
受保护的静态最终int MAX_值=5;//我们的常数
私有JFrame;
private JProgressBar progressBar=新的JProgressBar();
公共静态void main(字符串[]args){
invokeLater(新的Runnable(){
公开募捐{
试一试{
SwingThread2窗口=新的SwingThread2();
window.frame.setVisible(true);
}捕获(例外e){
e、 printStackTrace();
}
}
});
}
公共SwingThread2(){
初始化();
}
私有void初始化(){
frame=新的JFrame();
//frame.setBounds(100100450300);//避免这种情况
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JScrollPane scrollPane=新的JScrollPane();
frame.getContentPane().add(滚动窗格,BorderLayout.CENTER);
JTextArea textArea=新的JTextArea(15,40);
scrollPane.setViewportView(文本区域);
JButton btnNewButton=新JButton(“新按钮”);
scrollPane.setColumnHeaderView(btnNewButton);
addActionListener(新ActionListener(){
已执行的公共无效操作(操作事件arg0){
//计时器滴答之间的延迟:1000
int timerDelay=1000;
新计时器(timerDelay,新ActionListener(){
专用整数计数器=0;
@凌驾
已执行的公共无效操作(操作事件e){
//定时器停止条件
如果(计数器>=MAX\u值){//MAX\u值是一个常数
//int=5
((计时器)e.getSource()).stop();
}否则{
textArea.append(“值”+计数器+“\n”);
}
计数器+++;//递增计时器的计数器变量
}
}).start();
}
});
progressBar.SetStringPaint(真);
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.*;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.Random;
import java.util.concurrent.ExecutionException;
import javax.swing.*;
public class SwingThread2 {
protected static final int MAX_VALUE = 5; // our constant
private JFrame frame;
private JProgressBar progressBar = new JProgressBar();
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
SwingThread2 window = new SwingThread2();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public SwingThread2() {
initialize();
}
private void initialize() {
frame = new JFrame();
// frame.setBounds(100, 100, 450, 300); // avoid this
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JScrollPane scrollPane = new JScrollPane();
frame.getContentPane().add(scrollPane, BorderLayout.CENTER);
JTextArea textArea = new JTextArea(15, 40);
scrollPane.setViewportView(textArea);
JButton btnNewButton = new JButton("New button");
scrollPane.setColumnHeaderView(btnNewButton);
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
// delay between timer ticks: 1000
int timerDelay = 1000;
new Timer(timerDelay, new ActionListener() {
private int counter = 0;
@Override
public void actionPerformed(ActionEvent e) {
// timer's stopping condition
if (counter >= MAX_VALUE) { // MAX_VALUE is a constant
// int = 5
((Timer) e.getSource()).stop();
} else {
textArea.append("Value " + counter + "\n");
}
counter++; // increment timer's counter variable
}
}).start();
}
});
progressBar.setStringPainted(true);
JPanel bottomPanel = new JPanel();
bottomPanel.setLayout(new BoxLayout(bottomPanel, BoxLayout.LINE_AXIS));
bottomPanel.add(new JButton(new MyAction("Press Me")));
bottomPanel.add(progressBar);
frame.getContentPane().add(bottomPanel, BorderLayout.PAGE_END);
// better to avoid setting sizes but instead to
// let the components size themselves vis pack
frame.pack();
frame.setLocationRelativeTo(null);
}
private class MyAction extends AbstractAction {
public MyAction(String name) {
super(name);
int mnemonic = (int) name.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
}
public void actionPerformed(ActionEvent e) {
progressBar.setValue(0);
setEnabled(false);
MyWorker myWorker = new MyWorker();
myWorker.addPropertyChangeListener(new WorkerListener(this));
myWorker.execute();
}
}
private class WorkerListener implements PropertyChangeListener {
private Action action;
public WorkerListener(Action myAction) {
this.action = myAction;
}
@Override
public void propertyChange(PropertyChangeEvent evt) {
if ("progress".equals(evt.getPropertyName())) {
int progress = (int) evt.getNewValue();
progressBar.setValue(progress);
} else if ("state".equals(evt.getPropertyName())) {
if (evt.getNewValue() == SwingWorker.StateValue.DONE) {
action.setEnabled(true);
@SuppressWarnings("rawtypes")
SwingWorker worker = (SwingWorker) evt.getSource();
try {
// always want to call get to trap and act on
// any exceptions that the worker might cause
// do this even though get returns nothing
worker.get();
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
}
}
}
}
}
private class MyWorker extends SwingWorker<Void, Void> {
private static final int MULTIPLIER = 80;
private int counter = 0;
private Random random = new Random();
@Override
protected Void doInBackground() throws Exception {
while (counter < 100) {
int increment = random.nextInt(10);
Thread.sleep(increment * MULTIPLIER);
counter += increment;
counter = Math.min(counter, 100);
setProgress(counter);
}
return null;
}
}
}