Java 如何每x秒重新绘制一个jpanel？
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时间：2020-08-13 13:24:25 来源:igfitidea点击:
How to repaint a jpanel every x seconds?
提问by Alessandro
i would like to know how to repaint and update the background of a JPanel every x seconds...This is my code:
我想知道如何每 x 秒重新绘制和更新 JPanel 的背景......这是我的代码：
package view;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;
public class GamePanel extends JPanel {
/**
*
*/
private static final long serialVersionUID = 1L;
private final JLabel score;
private final static String[] BACKGROUND_COLORS = {"black", "blue", "darkpurple", "purple"};
private int i = 0;
public GamePanel() {
this.score = new JLabel("Score: ");
this.score.setBounds(0, 0, 40, 20);
this.score.setOpaque(false);
this.score.setForeground(Color.GREEN);
this.add(score);
}
@Override
protected void paintComponent(final Graphics g) {
super.paintComponent(g);
//Image background = new ImageIcon(this.getClass().getResource("/images/" + BACKGROUND_COLORS[i] + "Background.png")).getImage();
//g.drawImage(background, 0, 0, null);
Timer timer = new Timer(1000, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
Image background = new ImageIcon(this.getClass().getResource("/images/" + BACKGROUND_COLORS[i] + "Background.png")).getImage();
g.drawImage(background, 0, 0, null);
revalidate();
repaint();
System.out.println("trying my timer");
i++;
if (i == 4) {
i = 0;
}
}
});
timer.start();
}
}
I have 2 issues with this code: 1- The JPanel doesn't get painted at all. 2- The first print is ok, then the the number of prints is doubled each time. Any suggestion? Thank you in advance
这段代码有两个问题：1- JPanel 根本没有被绘制。2- 第一次打印没问题，然后每次打印数量翻倍。有什么建议吗？先感谢您
UPDATE: I solved the problem in this way:
更新：我以这种方式解决了这个问题：
package view;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;
public class GamePanel extends JPanel {
/**
*
*/
private static final long serialVersionUID = 1L;
private final JLabel score;
private int i = 0;
private final static String[] BACKGROUND_COLORS = {"black", "blue", "darkpurple", "purple"};
private final static int DELAY = 10000;
public GamePanel() {
this.score = new JLabel("Score: ");
this.score.setBounds(0, 0, 40, 20);
this.score.setOpaque(false);
this.score.setForeground(Color.GREEN);
this.add(score);
Timer timer = new Timer(DELAY, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
i++;
if (i == 4) {
i = 0;
}
}
});
timer.start();
}
@Override
protected void paintComponent(final Graphics g) {
super.paintComponent(g);
Image background = new ImageIcon(this.getClass().getResource("/images/" + BACKGROUND_COLORS[this.i] + "Background.png")).getImage();
g.drawImage(background, 0, 0, null);
revalidate();
repaint();
}
UPDATE 2:
更新 2：
package view;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;
public class GamePanel extends JPanel {
/**
*
*/
private static final long serialVersionUID = 1L;
private final JLabel score;
private int currentImage;
private final List<Image> backgrounds = new ArrayList<>();
private static final String[] BACKGROUND_COLORS = {"black", "blue", "darkpurple", "purple"};
private static final int DELAY = 1000;
public GamePanel() {
super();
this.score = new JLabel("Score: ");
this.score.setBounds(0, 0, 40, 20);
this.score.setOpaque(false);
this.score.setForeground(Color.GREEN);
this.add(score);
for (final String s : BACKGROUND_COLORS) {
backgrounds.add(new ImageIcon(this.getClass().getResource("/images/" + s + "Background.png")).getImage());
}
final Timer timer = new Timer(DELAY, new ActionListener() {
@Override
public void actionPerformed(final ActionEvent e) {
repaint();
currentImage++;
if (currentImage == BACKGROUND_COLORS.length) {
currentImage = 0;
}
}
});
timer.start();
}
@Override
protected void paintComponent(final Graphics g) {
super.paintComponent(g);
g.drawImage(backgrounds.get(this.currentImage), 0, 0, null);
}
采纳答案by Masudul
Use Swing Timer,
使用摇摆计时器，
class GamePanel extends JPanel implements ActionListener{
Timer timer=new Timer(1000, this);
public GamePanel() {
timer.start();// Start the timer here.
}
public void actionPerformed(ActionEvent ev){
if(ev.getSource()==timer){
repaint();// this will call at every 1 second
}
}
