Java 如何使用paintComponent()执行多线程?
我创建了一个应用程序,其中包含一个正方形,每当它接触到框架边缘时都会反弹。我在应用程序中没有问题,问题是我不知道如何创建不同的线程,以便在框架中有多个正方形。 我尝试了多种方法,但我不知道应该在哪里创建线程。 我还注意到,只有当我将正方形直接添加到框架中时,它才可见,而当我将其放入JPanel中时,它不可见 Square.javaJava 如何使用paintComponent()执行多线程?,java,multithreading,swing,graphics2d,Java,Multithreading,Swing,Graphics2d,我创建了一个应用程序,其中包含一个正方形,每当它接触到框架边缘时都会反弹。我在应用程序中没有问题,问题是我不知道如何创建不同的线程,以便在框架中有多个正方形。 我尝试了多种方法,但我不知道应该在哪里创建线程。 我还注意到,只有当我将正方形直接添加到框架中时,它才可见,而当我将其放入JPanel中时,它不可见 Square.java public class Square extends JComponent implements ActionListener { int width = 2
public class Square extends JComponent implements ActionListener {
int width = 20;
int height = 20;
double y = Math.random() * 360;
double x = Math.random() * 360;
boolean xMax = false;
boolean yMax = false;
boolean xMin = true;
boolean yMin = true;
Rectangle2D.Double square = new Rectangle2D.Double(x, y, width, height);
public Square() {
Timer t = new Timer(2, this);
t.start();
}
public void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
super.paintComponent(g);
g2.setColor(Color.BLUE);
g2.fill(square);
x_y_rules();
}
public void x_y_rules() {
if (xMax == true) {
x = x - 0.5;
if (x <= 0) {
xMax = false;
}
} else {
x = x + 0.5;
if (x >= this.getWidth()) {
xMax = true;
}
}
if (yMax == true) {
y = y - 0.5;
if (y <= 0) {
yMax = false;
}
} else {
y = y + 0.5;
if (y >= this.getHeight()) {
yMax = true;
}
}
square.setFrame(x, y, width, height);
}
@Override
public void actionPerformed(ActionEvent arg0) {
repaint();
}
}
尽管我在计时器中设置了时间2,但正方形移动非常缓慢,这正常吗?问题:
x\u y\u rules()
方法调用。把它拿出来,因为它不属于那里,而是把它放在计时器的ActionListener代码中它属于的地方李>
getPreferredSize()
,并让它返回一个合理的维度值setVisible(true)
,这是一个禁忌好的,我在square类中放置了一个getPreferedSize(),但我遇到了一个问题:这些正方形不是“在一起”,就像它们在单独的面板上反弹一样 那么你的程序结构就被破坏了。您确实不想创建单独的Swing组件,事实上,您的Square类不应该扩展JComponent或JPanel。相当于
- Square应该是一个逻辑类,一个从零扩展而来的类(默认对象除外)李>
- 给它一个绘图方法,比如说
publicsvoiddraw(graphicsg){….}
- 创建一个扩展JPanel的类,比如称为
,并重写其paintComponent方法DrawingPanel
- 为DrawingPanel类指定一个
,以便它可以容纳多个方形对象ArrayList
- 给DrawingPanel类一个摆动计时器
- 在DrawingPanel类的计时器中,让它更新ArrayList中所有正方形的位置,然后调用
repaint()
- 在paintComponent方法中,使用for循环遍历列表中的所有正方形,并调用每个正方形的draw方法
导入java.awt.Color;
导入java.awt.Dimension;
导入java.awt.Graphics;
导入java.awt.Image;
导入java.awt.event.ActionEvent;
导入java.awt.event.ActionListener;
导入java.awt.image.buffereImage;
导入java.util.ArrayList;
导入java.util.List;
导入javax.swing.*;
@抑制警告(“串行”)
公共类DrawingPanel扩展了JPanel{
专用静态最终整型预调W=600;
私有静态final int PREF_H=PREF_W;
专用静态最终int定时器_延迟=20;
私有静态最终颜色[]方形颜色={Color.BLUE,Color.CYAN,Color.DARK\u GRAY,
颜色。黑色,颜色。灰色,颜色。绿色,颜色。浅灰色,颜色。洋红,颜色。橙色,
Color.PINK、Color.RED、Color.YELLOW};
List squareList=新的ArrayList();
公共绘图面板(){
//创建一组正方形
对于(int i=0;icreateAndShowGui());
}
}
//此类*不*扩展JPanel或JComponent
阶级广场{
公共静态最终整数宽度=20;
//广场位置
私人双sqrX;
私人双平方米;
//X和Y速度
私人双重征税;
私人双三角酒店;
//绘图板JPanel的宽度和高度
私有int-dpWidth;
私人室内高度;
//要绘制的图像
私有图像;
公共广场(彩色、int-dpWidth、int-dpHeight){
this.dpWidth=dpWidth;
this.dpHeight=dpHeight;
//以随机速度在随机位置创建正方形
sqrX=Math.random()*(dpWidth-WIDTH);
sqrY=Math.random()*(dpHeight-WIDTH);
deltaX=Math.random()*10-5;
判定元件
public class App extends JFrame {
public static void main(String[] args) {
JFrame jf = new JFrame();
Square sqr = new Square();
jf.setSize(400, 400);
jf.setVisible(true);
jf.add(sqr);
jf.setDefaultCloseOperation(EXIT_ON_CLOSE);
jf.setLocationRelativeTo(null);
}
}
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
@SuppressWarnings("serial")
public class DrawingPanel extends JPanel {
private static final int PREF_W = 600;
private static final int PREF_H = PREF_W;
private static final int TIMER_DELAY = 20;
private static final Color[] SQUARE_COLOR = { Color.BLUE, Color.CYAN, Color.DARK_GRAY,
Color.BLACK, Color.GRAY, Color.GREEN, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,
Color.PINK, Color.RED, Color.YELLOW };
List<Square> squareList = new ArrayList<>();
public DrawingPanel() {
// create a bunch of squares
for (int i = 0; i < SQUARE_COLOR.length; i++) {
squareList.add(new Square(SQUARE_COLOR[i], PREF_W, PREF_H));
}
setBackground(Color.WHITE);
// create and start the timer
new Timer(TIMER_DELAY, new TimerListener()).start();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
// simply draw all the squares in the list
for (Square square : squareList) {
square.draw(g);
}
}
// set size of JPanel
@Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private class TimerListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
// simply iterate through list and move all squares
for (Square square : squareList) {
square.move();
}
repaint(); // then repaint the GUI
}
}
private static void createAndShowGui() {
DrawingPanel mainPanel = new DrawingPanel();
JFrame frame = new JFrame("Drawing Panel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
// this class does *not* extend JPanel or JComponent
class Square {
public static final int WIDTH = 20;
// location of Square
private double sqrX;
private double sqrY;
// X and Y speed
private double deltaX;
private double deltaY;
// width and height of DrawingPanel JPanel
private int dpWidth;
private int dpHeight;
// image to draw
private Image image;
public Square(Color color, int dpWidth, int dpHeight) {
this.dpWidth = dpWidth;
this.dpHeight = dpHeight;
// create square at random location with random speed
sqrX = Math.random() * (dpWidth - WIDTH);
sqrY = Math.random() * (dpHeight - WIDTH);
deltaX = Math.random() * 10 - 5;
deltaY = Math.random() * 10 - 5;
// one way to draw it is to create an image and draw it
image = new BufferedImage(WIDTH, WIDTH, BufferedImage.TYPE_INT_ARGB);
Graphics g = image.getGraphics();
g.setColor(color);
g.fillRect(0, 0, WIDTH, WIDTH);
g.dispose();
}
public void move() {
// check that we're not hitting boundaries
if (sqrX + deltaX < 0) {
deltaX = Math.abs(deltaX);
}
if (sqrX + deltaX + WIDTH >= dpWidth) {
deltaX = -Math.abs(deltaX);
}
sqrX += deltaX;
// check that we're not hitting boundaries
if (sqrY + deltaY < 0) {
deltaY = Math.abs(deltaY);
}
if (sqrY + deltaY + WIDTH >= dpHeight) {
deltaY = -Math.abs(deltaY);
}
sqrY += deltaY;
}
public void draw(Graphics g) {
int x = (int) sqrX;
int y = (int) sqrY;
g.drawImage(image, x, y, null);
}
}