Java 使用ActionListener添加新元素
大家好，我有一个按钮，可以在我设置的ArrayList中添加一个新球。而不是添加一个新的球，它只是加快了球，我已经去。 此CreateCircle创建球：Java 使用ActionListener添加新元素,java,swing,arraylist,jpanel,Java,Swing,Arraylist,Jpanel,大家好，我有一个按钮，可以在我设置的ArrayList中添加一个新球。而不是添加一个新的球，它只是加快了球，我已经去。 此CreateCircle创建球： import java.awt.*; import java.awt.event.*; import java.awt.geom.*; import javax.swing.*; @SuppressWarnings("serial") public class CreateCircle extends JPanel { /* Ports J
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.*;
@SuppressWarnings("serial")
public class CreateCircle extends JPanel {
/* Ports JFrame width, height from BouncingDrawFrame */
static double c, d;
/* Ports desired size of Circle */
static int r = 20; // Initial Value 20
/* Ports timer delay from BouncingDrawFrame */
static int z = 10; // Initial Value 10
/* Timer to control speed */
static Timer t = new Timer(z, null);
/* X,Y points to start, speed of movement */
static double x, y, velX = 1, velY = 1;
/* Ports color choice from BouncingDrawFrame */
static Color myColor;
public CreateCircle(int a, int b) {
/* Height of Frame */
c = a;
/* Width of Frame */
d = b;
t.start();
t.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
/* "Bounces" the Ball off the sides */
if (x < 0 || x > (d - (r + 2))) {
velX = -velX;
}
/* "Bounces" the Ball off the top and bottom */
if (y < 0 || y > (c - (r + 30))) {
velY = -velY;
}
/* Moves ball 2 pixels each timer action */
x += velX;
y += velY;
repaint();
}
});
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
Ellipse2D circle = new Ellipse2D.Double(x, y, r, r);
g2.setColor(myColor);
g2.fill(circle);
}
}
CreateCirclestaticCreateCircleCreateCircleimport java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
@SuppressWarnings("serial")
public class BouncingLabels extends JFrame {
// this is our bouncing label component. it bounces around its parent. this could
// be pulled out into its own class file; its in here to keep the example self
// contained.
static class BouncingLabel extends JLabel {
private int fieldWidth, fieldHeight; // width/height of parent at creation time.
private int velX = 1, velY = 1; // current x and y velocity.
// constructor sets base label properties and starts a timer.
public BouncingLabel (int fieldWidth, int fieldHeight) {
this.fieldWidth = fieldWidth;
this.fieldHeight = fieldHeight;
setBounds(0, 0, 60, 20);
setOpaque(true);
setBackground(Color.RED);
setForeground(Color.WHITE);
setText("HELLO");
setVisible(true);
// timer will call step() every 10ms.
new Timer(10, new ActionListener() {
@Override public void actionPerformed (ActionEvent e) {
step();
}
}).start();
}
// step updates the component position. note that no explicit painting is done.
private void step () {
int x = getX();
int y = getY();
int maxx = fieldWidth - getWidth();
int maxy = fieldHeight - getHeight();
x += velX;
y += velY;
if ((x >= maxx && velX > 0) || (x <= 0 && velX < 0))
velX = -velX;
if ((y >= maxy && velY > 0) || (y <= 0 && velY < 0))
velY = -velY;
setLocation(x, y);
}
}
// BouncingLabels is our main frame; click on it to add a label.
public BouncingLabels () {
// work with the content pane, not the frame itself.
final Container c = getContentPane();
c.setPreferredSize(new Dimension(300, 300));
c.setLayout(null);
setResizable(false);
pack();
// add an initial bouncing object.
c.add(new BouncingLabel(c.getWidth(), c.getHeight()));
// clicking on the frame will add a new object.
addMouseListener(new MouseAdapter() {
@Override public void mouseClicked (MouseEvent e) {
if (e.getButton() == MouseEvent.BUTTON1)
c.add(new BouncingLabel(c.getWidth(), c.getHeight()));
}
});
}
// main method creates and shows a BouncingLabels frame.
public static void main (String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override public void run () {
BouncingLabels b = new BouncingLabels();
b.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
b.setLocationRelativeTo(null);
b.setVisible(true);
}
});
}
}
导入java.awt.Color；
导入java.awt.Container；
导入java.awt.Dimension；
导入java.awt.event.ActionEvent；
导入java.awt.event.ActionListener；
导入java.awt.event.MouseAdapter；
导入java.awt.event.MouseEvent；
导入javax.swing.JFrame；
导入javax.swing.JLabel；
导入javax.swing.SwingUtilities；
导入javax.swing.Timer；
@抑制警告（“串行”）
公共类BouncingLabels扩展JFrame{
//这是我们的反弹标签组件。它围绕其父对象反弹。这可能会
//被拖出到它自己的类文件中；在这里保存示例本身
//包含。
静态类BouncingLabel扩展了JLabel{
private int fieldWidth，fieldHeight；//创建时父项的宽度/高度。
private int velX=1，velY=1；//当前的x和y速度。
//构造函数设置基本标签属性并启动计时器。
公共BouncingLabel（int fieldWidth、int fieldHeight）{
this.fieldWidth=fieldWidth；
this.fieldHeight=fieldHeight；
立根（0,0,60,20）；
set不透明（true）；
挫折地面（颜色：红色）；
设置前景（颜色：白色）；
setText（“你好”）；
setVisible（真）；
//计时器将每隔10毫秒调用步骤（）。
新计时器（10，新ActionListener（）{
@覆盖已执行的公共无效操作（ActionEvent e）{
步骤（）；
}
}).start（）；
}
//步骤更新组件位置。请注意，没有进行显式绘制。
私有无效步骤（）{
intx=getX（）；
int y=getY（）；
int maxx=fieldWidth-getWidth（）；
int maxy=fieldHeight-getHeight（）；
x+=velX；
y+=0；
如果（（x>=maxx&&velX>0）| |（x=maxy&&velY>0）|（y您的CreateCircle
类中的每个字段都是静态的
，这意味着它们在CreateCircle
的所有实例之间共享。本质上，这意味着您对其中一个球所做的每个计算都发生在每个球上，并且每个球都是相同的
如果希望这些属性与CreateCircle
的特定实例相关联，则必须将这些属性设置为非静态
您可能希望查看有关实例和类成员的官方教程
根据您的问题更新如下：闪烁：我创建了一个反弹JLabel的示例（），展示了如何做到这一点，并让Swing负责重新绘制等。这里还有：
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
@SuppressWarnings("serial")
public class BouncingLabels extends JFrame {
// this is our bouncing label component. it bounces around its parent. this could
// be pulled out into its own class file; its in here to keep the example self
// contained.
static class BouncingLabel extends JLabel {
private int fieldWidth, fieldHeight; // width/height of parent at creation time.
private int velX = 1, velY = 1; // current x and y velocity.
// constructor sets base label properties and starts a timer.
public BouncingLabel (int fieldWidth, int fieldHeight) {
this.fieldWidth = fieldWidth;
this.fieldHeight = fieldHeight;
setBounds(0, 0, 60, 20);
setOpaque(true);
setBackground(Color.RED);
setForeground(Color.WHITE);
setText("HELLO");
setVisible(true);
// timer will call step() every 10ms.
new Timer(10, new ActionListener() {
@Override public void actionPerformed (ActionEvent e) {
step();
}
}).start();
}
// step updates the component position. note that no explicit painting is done.
private void step () {
int x = getX();
int y = getY();
int maxx = fieldWidth - getWidth();
int maxy = fieldHeight - getHeight();
x += velX;
y += velY;
if ((x >= maxx && velX > 0) || (x <= 0 && velX < 0))
velX = -velX;
if ((y >= maxy && velY > 0) || (y <= 0 && velY < 0))
velY = -velY;
setLocation(x, y);
}
}
// BouncingLabels is our main frame; click on it to add a label.
public BouncingLabels () {
// work with the content pane, not the frame itself.
final Container c = getContentPane();
c.setPreferredSize(new Dimension(300, 300));
c.setLayout(null);
setResizable(false);
pack();
// add an initial bouncing object.
c.add(new BouncingLabel(c.getWidth(), c.getHeight()));
// clicking on the frame will add a new object.
addMouseListener(new MouseAdapter() {
@Override public void mouseClicked (MouseEvent e) {
if (e.getButton() == MouseEvent.BUTTON1)
c.add(new BouncingLabel(c.getWidth(), c.getHeight()));
}
});
}
// main method creates and shows a BouncingLabels frame.
public static void main (String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override public void run () {
BouncingLabels b = new BouncingLabels();
b.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
b.setLocationRelativeTo(null);
b.setVisible(true);
}
});
}
}
导入java.awt.Color；
导入java.awt.Container；
导入java.awt.Dimension；
导入java.awt.event.ActionEvent；
导入java.awt.event.ActionListener；
导入java.awt.event.MouseAdapter；
导入java.awt.event.MouseEvent；
导入javax.swing.JFrame；
导入javax.swing.JLabel；
导入javax.swing.SwingUtilities；
导入javax.swing.Timer；
@抑制警告（“串行”）
公共类BouncingLabels扩展JFrame{
//这是我们的反弹标签组件。它围绕其父对象反弹。这可能会
//被拖出到它自己的类文件中；在这里保存示例本身
//包含。
静态类BouncingLabel扩展了JLabel{
private int fieldWidth，fieldHeight；//创建时父项的宽度/高度。
private int velX=1，velY=1；//当前的x和y速度。
//构造函数设置基本标签属性并启动计时器。
公共BouncingLabel（int fieldWidth、int fieldHeight）{
this.fieldWidth=fieldWidth；
this.fieldHeight=fieldHeight；
立根（0,0,60,20）；
set不透明（true）；
挫折地面（颜色：红色）；
设置前景（颜色：白色）；
setText（“你好”）；
setVisible（真）；
//计时器将每隔10毫秒调用步骤（）。
新计时器（10，新ActionListener（）{
@覆盖已执行的公共无效操作（ActionEvent e）{
步骤（）；
}
}).start（）；
}
//步骤更新组件位置。请注意，没有进行显式绘制。
私有无效步骤（）{
intx=getX（）；
int y=getY（）；
int maxx=fieldWidth-getWidth（）；
int maxy=fieldHeight-getHeight（）；
x+=velX；
y+=0；
如果（（x>=maxx&&velX>0）| |（x=maxy&&velY>0）|（y）你过度使用了静态修饰符。编辑--我现在看到Jason C在答案中陈述。1+到他的答案。你过度使用了静态修饰符。编辑--我现在看到Jason C在答案中陈述。1+到他的答案。谢谢你的工作，我从所有变量和字段中删除了静态修饰符，但是现在当我创建一个新的球时，它会闪烁。我需要把repaint（）放在任何地方吗？你的代码有很多问题，尤其是每一个问题
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
@SuppressWarnings("serial")
public class BouncingLabels extends JFrame {
// this is our bouncing label component. it bounces around its parent. this could
// be pulled out into its own class file; its in here to keep the example self
// contained.
static class BouncingLabel extends JLabel {
private int fieldWidth, fieldHeight; // width/height of parent at creation time.
private int velX = 1, velY = 1; // current x and y velocity.
// constructor sets base label properties and starts a timer.
public BouncingLabel (int fieldWidth, int fieldHeight) {
this.fieldWidth = fieldWidth;
this.fieldHeight = fieldHeight;
setBounds(0, 0, 60, 20);
setOpaque(true);
setBackground(Color.RED);
setForeground(Color.WHITE);
setText("HELLO");
setVisible(true);
// timer will call step() every 10ms.
new Timer(10, new ActionListener() {
@Override public void actionPerformed (ActionEvent e) {
step();
}
}).start();
}
// step updates the component position. note that no explicit painting is done.
private void step () {
int x = getX();
int y = getY();
int maxx = fieldWidth - getWidth();
int maxy = fieldHeight - getHeight();
x += velX;
y += velY;
if ((x >= maxx && velX > 0) || (x <= 0 && velX < 0))
velX = -velX;
if ((y >= maxy && velY > 0) || (y <= 0 && velY < 0))
velY = -velY;
setLocation(x, y);
}
}
// BouncingLabels is our main frame; click on it to add a label.
public BouncingLabels () {
// work with the content pane, not the frame itself.
final Container c = getContentPane();
c.setPreferredSize(new Dimension(300, 300));
c.setLayout(null);
setResizable(false);
pack();
// add an initial bouncing object.
c.add(new BouncingLabel(c.getWidth(), c.getHeight()));
// clicking on the frame will add a new object.
addMouseListener(new MouseAdapter() {
@Override public void mouseClicked (MouseEvent e) {
if (e.getButton() == MouseEvent.BUTTON1)
c.add(new BouncingLabel(c.getWidth(), c.getHeight()));
}
});
}
// main method creates and shows a BouncingLabels frame.
public static void main (String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override public void run () {
BouncingLabels b = new BouncingLabels();
b.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
b.setLocationRelativeTo(null);
b.setVisible(true);
}
});
}
}