我的t.stop（）;方法不起作用。我疯狂地想弄清楚为什么我的停止方法不起作用。
我在我的代码中使用了一个计时器，我无法让它停下来。任何人都可以看看它并告诉我发生了什么？：
/*Gilberto Rose*/
package homework2;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class MultipleBalls extends JFrame implements ActionListener
{
int dx = 2;
int dy = 2;
int x = 1;
int y = 1;
int i = 0;
public static void main(String[] args)
{
Runnable balls = new Ball2();
Thread thread1 = new Thread(balls);
thread1.run();
}
@Override
public void actionPerformed(ActionEvent arg0)
{
repaint();
System.out.println(i++);
}
}// End of Ball class
class Ball2 extends JPanel implements Runnable
{
MultipleBalls b = new MultipleBalls();
JButton g = new JButton("resume");
JButton f = new JButton("suspend");
JButton e = new JButton("-1");
JButton d = new JButton("+1");
List<Ball2> L = new ArrayList<Ball2>();
Timer t = new Timer(50, b);
public int x = 6;
public void loopstop()
{
t.stop();
}// end of loopstop method
Ball2()
{
controller4();
controller3();
controller2();
controller();
add(d);
add(e);
add(f);
add(g);
}// End of Ball2 constructor
public void run()
{
Ball2 c = new Ball2();
b.setSize(500, 500);
b.setVisible(true);
b.add(c);
t.start();
} // End of run method
public void controller()
{
d.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
L.add(new Ball2());
}
});
}// End of controller
public void controller2()
{
e.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
System.out.println("subtracter");
L.remove(L.size()-1);
}
});
}// End of controller2
public void controller3()
{
f.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
loopstop();
}
});
}// End of controller3
public void controller4()
{
g.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
System.out.println("Resume");
}
});
}// End of controller4
public void paintComponent(Graphics g)
{
if(L.size() > 0)
{
int i = 0;
do
{
g.fillOval(L.get(i).ballx(), L.get(i).bally(), 90, 90);
i++;
}while(i < L.size() && true ); // End of Do while loop
}// End of if statement
}// End of paintComponent
MultipleBalls bb = new MultipleBalls();
public int ballx()
{
if (bb.x == 0 || bb.x == 500)
{
bb.dx *= -1;
} // End of if statement
bb.x += bb.dx;
return bb.x;
}
public int bally()
{
if (bb.y == 0 || bb.y == 500 )
{
bb.dy *= -1;
}// end of if statement
bb.y += bb.dy;
return bb.y;
}// End of bally
}// End of Ball2 class
答案 0 :(得分：4)
你的代码非常复杂，我相信它会受到cyclomatic complexity的影响，所以很难让你或我们看到什么对象正在创造其他对象，以及运行什么。这是你的问题。你有至少两个MultipleBall对象，两个Ball2对象，你正在为其中一个Ball2对象启动Timer并为另一个对象停止它。
解决方案：大大简化此代码。
另请注意，您几乎从不在Thread对象上调用run()，而是start()，但话虽如此，我甚至不确定您是否应该使用Thread对象使用它。
修改
我的主要课程很简单，只需要一个主要方法和支持方法即可开始。类似的东西：
public class MultipleBalls {
private static void createAndShowGui() {
BallsPanel mainPanel = new BallsPanel();
JFrame frame = new JFrame("Multiple Balls");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
修改
关于关注点分离的例子：
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.swing.*;
public class MultipleBallsZ {
private static void createAndShowGui() {
BallsPanelZ ballsPanel = new BallsPanelZ();
new Control(ballsPanel);
JFrame frame = new JFrame("Multiple Balls");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(ballsPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
@SuppressWarnings("serial")
class BallsPanelZ extends JPanel {
private static final int TIMER_DELAY = 200;
private static final int PREF_W = 400;
private static final int PREF_H = PREF_W;
private Timer timer = new Timer(TIMER_DELAY, new TimerListener());
private int counter = 0;
private Control control = null;
public BallsPanelZ() {
timer.start();
}
@Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
public Timer getTimer() {
return timer;
}
private class TimerListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
counter++;
System.out.printf("Count: %03d%n", counter);
}
}
public void setControl(Control control) {
this.control = control;
for (Action action : control) {
add(new JButton(action));
}
}
}
@SuppressWarnings("serial")
class Control implements Iterable<Action> {
private List<Action> actionList = new ArrayList<>();
private BallsPanelZ ballsPanel;
public Control(BallsPanelZ ballsPanel) {
actionList.add(new PauseAction());
actionList.add(new ResumeAction());
this.ballsPanel = ballsPanel;
ballsPanel.setControl(this);
}
private class PauseAction extends AbstractAction {
public PauseAction() {
super ("Timer Pause");
putValue(MNEMONIC_KEY, KeyEvent.VK_P);
}
@Override
public void actionPerformed(ActionEvent e) {
ballsPanel.getTimer().stop();
}
}
private class ResumeAction extends AbstractAction {
public ResumeAction() {
super("Timer Resume");
putValue(MNEMONIC_KEY, KeyEvent.VK_R);
putValue(DISPLAYED_MNEMONIC_INDEX_KEY, 6);
}
@Override
public void actionPerformed(ActionEvent e) {
ballsPanel.getTimer().restart();
}
}
@Override
public Iterator<Action> iterator() {
return actionList.iterator();
}
}