Java 用按钮停止和启动循环
我试图控制我的程序中的while循环,以根据用户输入停止和启动。我用一个按钮尝试了这一点,它的“开始”部分工作,但是代码进入了一个无限循环,如果不手动终止它,我就无法停止。以下是我的全部代码: 标题类Java 用按钮停止和启动循环,java,swing,button,while-loop,Java,Swing,Button,While Loop,我试图控制我的程序中的while循环,以根据用户输入停止和启动。我用一个按钮尝试了这一点,它的“开始”部分工作,但是代码进入了一个无限循环,如果不手动终止它,我就无法停止。以下是我的全部代码: 标题类 package test; import javax.swing.JFrame; public class headerClass { public static void main (String[] args){ frameClass
package test;
import javax.swing.JFrame;
public class headerClass {
public static void main (String[] args){
frameClass frame = new frameClass();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(150,75);
frame.setVisible(true);
}
}
package test;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class frameClass extends JFrame {
private JButton click;
public frameClass(){
setLayout(new FlowLayout());
click = new JButton("Stop Loop");
add(click);
thehandler handler = new thehandler();
click.addActionListener(handler);
}
private class thehandler implements ActionListener{
public void actionPerformed(ActionEvent e){
if(e.getSource()==click){
looper loop = new looper();
looper.buttonSet = !looper.buttonSet;
}
}
}
}
package test;
public class looper {
public static boolean buttonSet;
public looper(){
while (buttonSet==false){
System.out.println("aaa");
}
}
}
框架类
package test;
import javax.swing.JFrame;
public class headerClass {
public static void main (String[] args){
frameClass frame = new frameClass();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(150,75);
frame.setVisible(true);
}
}
package test;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class frameClass extends JFrame {
private JButton click;
public frameClass(){
setLayout(new FlowLayout());
click = new JButton("Stop Loop");
add(click);
thehandler handler = new thehandler();
click.addActionListener(handler);
}
private class thehandler implements ActionListener{
public void actionPerformed(ActionEvent e){
if(e.getSource()==click){
looper loop = new looper();
looper.buttonSet = !looper.buttonSet;
}
}
}
}
package test;
public class looper {
public static boolean buttonSet;
public looper(){
while (buttonSet==false){
System.out.println("aaa");
}
}
}
循环类
package test;
import javax.swing.JFrame;
public class headerClass {
public static void main (String[] args){
frameClass frame = new frameClass();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(150,75);
frame.setVisible(true);
}
}
package test;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class frameClass extends JFrame {
private JButton click;
public frameClass(){
setLayout(new FlowLayout());
click = new JButton("Stop Loop");
add(click);
thehandler handler = new thehandler();
click.addActionListener(handler);
}
private class thehandler implements ActionListener{
public void actionPerformed(ActionEvent e){
if(e.getSource()==click){
looper loop = new looper();
looper.buttonSet = !looper.buttonSet;
}
}
}
}
package test;
public class looper {
public static boolean buttonSet;
public looper(){
while (buttonSet==false){
System.out.println("aaa");
}
}
}
如果进入无限循环,如何修复此问题并停止?Swing是一个单线程框架,这意味着在循环运行时,事件调度线程被阻止,无法处理新事件,包括重新绘制请求 您需要在自己的线程上下文中启动Looper类。这也意味着您的循环标志需要声明为
volatile
,或者您应该使用AtomicBoolean
,以便跨线程边界检查和修改状态
例如
public class Looper implements Runnable {
private AtomicBoolean keepRunning;
public Looper() {
keepRunning = new AtomicBoolean(true);
}
public void stop() {
keepRunning.set(false);
}
@Override
public void run() {
while (keepRunning.get()) {
System.out.println("aaa");
}
}
}
那么你也许可以使用像
private class thehandler implements ActionListener {
private Looper looper;
public void actionPerformed(ActionEvent e) {
if (e.getSource() == click) {
if (looper == null) {
looper = new Looper();
Thread t = new Thread(looper);
t.start();
} else {
looper.stop();
looper = null;
}
}
}
}
要运行它
查看和了解更多详细信息
还要注意,Swing不是线程安全的,您永远不应该从EDT上下文的外部创建或修改UI。问题是您启动了一个无限循环,并试图在同一线程中终止它。这不起作用,因为VM在一个线程中执行一个又一个任务。它将在循环结束后直接执行命令停止
循环器
,但无限循环永远不会结束。所以它不能像这样被阻止。
您需要为活套创建第二个
线程。这样,您就可以从主线程停止它 你必须在一个单独的线程中启动“looper”。只是一个注释。。。Java中的类名应该是PascalCase,而不是camelCase。