Java代码中的计时器问题
对于家庭作业，我必须制作一个程序，在这个程序中，一个窗口用三个按钮打开：Drop、Retrieve和Quit。按下drop（下降）按钮时，一个圆圈从显示面板的顶部下降到底部并停留在那里。当按下Retrieve（检索）按钮时，一条线应沿屏幕向下落至圆圈，并目视将圆圈拉回到屏幕顶部 我写了几乎所有我无法让线回到屏幕上的东西，在我的代码中，只有球做了，线保持在那里Java代码中的计时器问题,java,graphics,timer,actionlistener,paintcomponent,Java,Graphics,Timer,Actionlistener,Paintcomponent,对于家庭作业，我必须制作一个程序，在这个程序中，一个窗口用三个按钮打开：Drop、Retrieve和Quit。按下drop（下降）按钮时，一个圆圈从显示面板的顶部下降到底部并停留在那里。当按下Retrieve（检索）按钮时，一条线应沿屏幕向下落至圆圈，并目视将圆圈拉回到屏幕顶部 我写了几乎所有我无法让线回到屏幕上的东西，在我的代码中，只有球做了，线保持在那里 import java.awt.*; import javax.swing.*; public class DisplayWindow
import java.awt.*;
import javax.swing.*;
public class DisplayWindow extends JFrame {
private Container c;
public DisplayWindow() {
super("Display");
c = this.getContentPane();
}
public void addPanel(JPanel p) {
c.add(p);
}
public void showFrame() {
this.pack();
this.setVisible(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class DropPanel extends JPanel implements ActionListener{
Timer ticker1= new Timer(20,this);
int x=150;
int y=0;
Timer ticker2= new Timer(20,this);
int x2=175;
int y2=0;
JButton drop=new JButton("Drop");
JButton retrieve=new JButton("Retrieve");
JButton quit=new JButton("Quit");
public DropPanel(){
setPreferredSize(new Dimension(300,600));
this.add(drop); drop.addActionListener(this);
this.add(retrieve); retrieve.addActionListener(this);
this.add(quit); quit.addActionListener(this);
}
public void paintComponent(Graphics g){
super.paintComponent(g);
g.drawOval(x,y,50,50);
g.drawLine(x2,0,x2,y2);
}
public void actionPerformed (ActionEvent e){
if(e.getSource() == ticker1){
if (y<550)
y=y+2;
}
if(e.getSource() == drop){
ticker1.start();
}
if(e.getSource()== ticker2){
if (y2<550){
y2=y2+2;
}
if (y2==550) {
ticker1.stop();
y=y-2;
y2=y2-2;
}
}
if(e.getSource() == retrieve){
ticker2.start();
if(y2==550){
y2=y2-2;
}
}
if(e.getSource()==quit){
System.exit(0);
}
repaint();
}
}
代码的格式使其难以阅读，但我认为我发现了错误：
if(e.getSource()== ticker2) {
if (y2<550) {
y2=y2+2;
}
if (y2==550) {
ticker1.stop();
y=y-2;
y2=y2-2;
}
}
if（例如getSource（）==ticker2）{
如果（y2从分离责任区域开始。试图将所有“行动”逻辑混合到一个方法中不仅是糟糕的设计，还会给你带来很多混乱
每个计时器都应该有自己的ActionListener
。这意味着您可以单独隔离逻辑并专注于自己的工作单元，而不必不必要地混合其他对象的状态
例如
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Ellipse2D;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class DropBall {
public static void main(String[] args) {
new DropBall();
}
public DropBall() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private JButton dropButton;
private JButton retrieveButton;
private AnimationPane animationPane;
public TestPane() {
setLayout(new BorderLayout());
animationPane = new AnimationPane();
add(animationPane);
dropButton = new JButton("Drop");
dropButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if (animationPane.canDrop()) {
animationPane.drop();
}
}
});
retrieveButton = new JButton("Retrieve");
retrieveButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if (animationPane.canRetrieve()) {
animationPane.retrieve();
}
}
});
JPanel buttonPane = new JPanel(new FlowLayout(FlowLayout.CENTER));
buttonPane.add(dropButton);
buttonPane.add(retrieveButton);
add(buttonPane, BorderLayout.SOUTH);
}
}
public static class AnimationPane extends JPanel {
protected static final int RUN_TIME = 1000;
private Timer dropTimer;
private Timer retrieveTimer;
private Ellipse2D ball;
private long startTime = -1;
private Point ballPoint;
private Point linePoint;
public AnimationPane() {
ball = new Ellipse2D.Float(0, 0, 10, 10);
dropTimer = new Timer(30, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
long duration = System.currentTimeMillis() - startTime;
float progress = (float) duration / (float) RUN_TIME;
if (progress > 1f) {
progress = 1f;
((Timer) e.getSource()).stop();
}
ballPoint = new Point();
ballPoint.x = getWidth() / 2;
ballPoint.y = Math.round(getHeight() * progress);
repaint();
}
});
dropTimer.setRepeats(true);
dropTimer.setCoalesce(true);
dropTimer.setInitialDelay(0);
retrieveTimer = new Timer(30, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
long duration = System.currentTimeMillis() - startTime;
float progress = (float) duration / (float) RUN_TIME;
linePoint = new Point();
linePoint.x = getWidth() / 2;
if (progress < 0.5f) {
linePoint.y = Math.round(getHeight() * (progress * 2));
} else {
if (progress > 1f) {
progress = 1f;
((Timer) e.getSource()).stop();
linePoint = null;
ballPoint = null;
} else {
linePoint.y = Math.round(getHeight() * (progress * 2));
linePoint.y = getHeight() - (linePoint.y - getHeight());
ballPoint.y = linePoint.y;
}
}
repaint();
}
});
retrieveTimer.setRepeats(true);
retrieveTimer.setCoalesce(true);
retrieveTimer.setInitialDelay(0);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
if (ballPoint != null) {
int x = (int) (ballPoint.x - (ball.getWidth() / 2));
int y = (int) (ballPoint.y - ball.getHeight());
g2d.translate(x, y);
g2d.draw(ball);
g2d.translate(-x, -y);
}
if (linePoint != null) {
int x = getWidth() / 2;
int y = 0;
g2d.drawLine(x, y, linePoint.x, linePoint.y);
}
g2d.dispose();
}
public boolean canDrop() {
return !dropTimer.isRunning() && !retrieveTimer.isRunning() && ballPoint == null;
}
public boolean canRetrieve() {
return !dropTimer.isRunning() && !retrieveTimer.isRunning() && ballPoint != null;
}
public void drop() {
startTime = System.currentTimeMillis();
dropTimer.start();
}
public void retrieve() {
startTime = System.currentTimeMillis();
retrieveTimer.start();
}
}
}
导入java.awt.BorderLayout；
导入java.awt.Dimension；
导入java.awt.EventQueue；
导入java.awt.FlowLayout；
导入java.awt.Graphics；
导入java.awt.Graphics2D；
导入java.awt.Point；
导入java.awt.Rectangle；
导入java.awt.event.ActionEvent；
导入java.awt.event.ActionListener；
导入java.awt.geom.Ellipse2D；
导入javax.swing.JButton；
导入javax.swing.JFrame；
导入javax.swing.JPanel；
导入javax.swing.Timer；
导入javax.swing.UIManager；
导入javax.swing.UnsupportedLookAndFeelException；
公共级吊球{
公共静态void main（字符串[]args）{
新落球（）；
}
公共投球{
invokeLater（新的Runnable（）{
@凌驾
公开募捐{
试一试{
UIManager.setLookAndFeel（UIManager.getSystemLookAndFeelClassName（））；
}catch（ClassNotFoundException |实例化Exception | IllegalacessException |不支持ookandfeelException ex）{
}
JFrame=新JFrame（“测试”）；
frame.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）；
frame.setLayout（新的BorderLayout（））；
frame.add（newtestpane（））；
frame.pack（）；
frame.setLocationRelativeTo（空）；
frame.setVisible（true）；
}
});
}
公共类TestPane扩展了JPanel{
私有JButton下拉按钮；
私有JButton检索按钮；
私有动画窗格动画窗格；
公共测试窗格（）{
setLayout（新的BorderLayout（））；
animationPane=新建animationPane（）；
添加（动画窗格）；
dropButton=新按钮（“Drop”）；
addActionListener（新ActionListener（）{
@凌驾
已执行的公共无效操作（操作事件e）{
if（animationPane.canDrop（））{
animationPane.drop（）；
}
}
});
retrieveButton=新的JButton（“Retrieve”）；
retrieveButton.addActionListener（新ActionListener（）{
@凌驾
已执行的公共无效操作（操作事件e）{
if（animationPane.canRetrieve（））{
animationPane.retrieve（）；
}
}
});
JPanel buttonPane=newjpanel（newflowlayout（FlowLayout.CENTER））；
按钮平面。添加（dropButton）；
按钮平面。添加（检索按钮）；
添加（按钮平面，边界布局。南部）；
}
}
公共静态类AnimationPane扩展了JPanel{
受保护静态最终整数运行时间=1000；
私人定时器；
私人定时器检索定时器；
私人椭圆球；
私有长startTime=-1；
私人圆珠笔；
专用点线点；
公共动画窗格（）{
ball=新的椭圆2d.浮动（0,0,10,10）；
dropTimer=新计时器（30，新ActionListener（）{
@凌驾
已执行的公共无效操作（操作事件e）{
长持续时间=System.currentTimeMillis（）-startTime；
浮动进度=（浮动）持续时间/（浮动）运行时间；
如果（进度>1f）{
进度=1f；
（（计时器）e.getSource（））.stop（）；
}
圆珠笔=新点（）；
ballPoint.x=getWidth（）/2；
ballPoint.y=Math.round（getHeight（）*进度）；
重新油漆（）；
}
});
dropTimer.setRepeats（真）；
dropTimer.setCoalesce（真）；
dropTimer.setInitialDelay（0）；
retrieveTimer=新计时器（30，新ActionListener（）{
@凌驾
已执行的公共无效操作（操作事件e）{
长持续时间=System.currentTimeMillis（）-startTime；
浮动进度=（浮动）持续时间/（浮动）运行时间；
linePoint=新点（）；
linePoint.x=getWidth（）/2；
如果（进度<0.5f）{
linePoint.y=Math.round（getHeight（）*（progress*2））；
}否则{
如果（进度>1f）{
进度=1f；
（（计时器）e.getSource（））.stop（）；
linePoint=null；
圆珠笔=零；
}否则{
linePoint.y=Math.round（getHeight（）*（progress*2））；
linePoint.y=getHeight（）-（linePoint.y-getHeight（））；
B
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Ellipse2D;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class DropBall {
public static void main(String[] args) {
new DropBall();
}
public DropBall() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private JButton dropButton;
private JButton retrieveButton;
private AnimationPane animationPane;
public TestPane() {
setLayout(new BorderLayout());
animationPane = new AnimationPane();
add(animationPane);
dropButton = new JButton("Drop");
dropButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if (animationPane.canDrop()) {
animationPane.drop();
}
}
});
retrieveButton = new JButton("Retrieve");
retrieveButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if (animationPane.canRetrieve()) {
animationPane.retrieve();
}
}
});
JPanel buttonPane = new JPanel(new FlowLayout(FlowLayout.CENTER));
buttonPane.add(dropButton);
buttonPane.add(retrieveButton);
add(buttonPane, BorderLayout.SOUTH);
}
}
public static class AnimationPane extends JPanel {
protected static final int RUN_TIME = 1000;
private Timer dropTimer;
private Timer retrieveTimer;
private Ellipse2D ball;
private long startTime = -1;
private Point ballPoint;
private Point linePoint;
public AnimationPane() {
ball = new Ellipse2D.Float(0, 0, 10, 10);
dropTimer = new Timer(30, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
long duration = System.currentTimeMillis() - startTime;
float progress = (float) duration / (float) RUN_TIME;
if (progress > 1f) {
progress = 1f;
((Timer) e.getSource()).stop();
}
ballPoint = new Point();
ballPoint.x = getWidth() / 2;
ballPoint.y = Math.round(getHeight() * progress);
repaint();
}
});
dropTimer.setRepeats(true);
dropTimer.setCoalesce(true);
dropTimer.setInitialDelay(0);
retrieveTimer = new Timer(30, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
long duration = System.currentTimeMillis() - startTime;
float progress = (float) duration / (float) RUN_TIME;
linePoint = new Point();
linePoint.x = getWidth() / 2;
if (progress < 0.5f) {
linePoint.y = Math.round(getHeight() * (progress * 2));
} else {
if (progress > 1f) {
progress = 1f;
((Timer) e.getSource()).stop();
linePoint = null;
ballPoint = null;
} else {
linePoint.y = Math.round(getHeight() * (progress * 2));
linePoint.y = getHeight() - (linePoint.y - getHeight());
ballPoint.y = linePoint.y;
}
}
repaint();
}
});
retrieveTimer.setRepeats(true);
retrieveTimer.setCoalesce(true);
retrieveTimer.setInitialDelay(0);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
if (ballPoint != null) {
int x = (int) (ballPoint.x - (ball.getWidth() / 2));
int y = (int) (ballPoint.y - ball.getHeight());
g2d.translate(x, y);
g2d.draw(ball);
g2d.translate(-x, -y);
}
if (linePoint != null) {
int x = getWidth() / 2;
int y = 0;
g2d.drawLine(x, y, linePoint.x, linePoint.y);
}
g2d.dispose();
}
public boolean canDrop() {
return !dropTimer.isRunning() && !retrieveTimer.isRunning() && ballPoint == null;
}
public boolean canRetrieve() {
return !dropTimer.isRunning() && !retrieveTimer.isRunning() && ballPoint != null;
}
public void drop() {
startTime = System.currentTimeMillis();
dropTimer.start();
}
public void retrieve() {
startTime = System.currentTimeMillis();
retrieveTimer.start();
}
}
}