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[英]Java, painted drawRect doesn't display until applet is resized with window borders
[英]Component won't display unless window is resized - Java
单击按钮后,图像可见性出现问题。 我有带框架的主要班级:
package superworld;
import java.awt.*;
import javax.swing.*;
public class SuperWorld {
public static void main(String[] args) {
JFrame frame= new JFrame();
frame.setSize(1050,650);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new SuperPanel());
frame.setVisible(true);
// frame.setResizable(false);
}
}
然后,我进入了Panel的所有组件类:
package superworld;
import javax.swing.*;
import java.awt.*;
import java.util.*;
import java.awt.event.*;
import javax.swing.Timer;
public class SuperPanel extends JPanel implements ActionListener{
Timer mainTimer;
public static final int HEIGHT = 550;
public static final int WIDTH = 1050;
int i;
int w=-100;
int h=-50;
ArrayList<SuperMiasto> miasta = new ArrayList<SuperMiasto>();
private JButton heroButton;
private JButton cywilButton;
public SuperPanel() {
mainTimer = new Timer(10,this);
heroButton = new HeroButton(this);
cywilButton = new CywilButton(this);
setLayout(null);
setPreferredSize(new Dimension(WIDTH, HEIGHT));
setBackground(Color.GREEN);
for(i=0;i<10;i++)
{
miasta.add( new SuperMiasto() );
miasta.get(i).x=w;
miasta.get(i).y=h;
miasta.get(i).imagelabel = new JLabel(miasta.get(i).image);
miasta.get(i).imagelabel.setBounds(miasta.get(i).x,miasta.get(i).y,miasta.get(i).image.getIconWidth(),miasta.get(i).image.getIconHeight());
add(miasta.get(i).imagelabel);
w=w+200;
if (w > WIDTH-200)
{
h=h+200;
w=-100;
}
}
}
public void paint(Graphics g){
super.paint(g);
Graphics2D g2d = (Graphics2D) g;
add(heroButton);
add(cywilButton);
}
public void actionPerformed(ActionEvent e) {
repaint();
}
}
和带按钮的类,添加带有图像的新对象:
package superworld;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
class HeroButton extends JButton implements ActionListener {
private JPanel buttonPanel;
HeroButton(JPanel buttonPanel) {
super("Dodaj hero");
this.buttonPanel = buttonPanel;
setBounds(0,500,150,50);
addActionListener(this);
}
@Override
public void actionPerformed(ActionEvent e) {
SuperLudzie batman = new SuperLudzie();
batman.imagelabel = new JLabel(batman.image);
batman.imagelabel.setBounds(50,50,batman.image.getIconWidth(),batman.image.getIconHeight());
buttonPanel.add(batman.imagelabel);
}
}
这个SuperLudzie的类别:
package superworld;
import java.awt.*;
import javax.swing.*;
public class SuperLudzie {
private String imie;
private int zycie;
private int inteligencja;
private int wytrzymalosc;
private int sila;
private int umiejetnosci_walki;
private int x,y;
ImageIcon image = new ImageIcon("C:/Users/Zuzanna Sawala/Moje dokumenty/NetBeansProjects/SuperWorld/mysz.jpg");
JLabel imagelabel;
}
一切正常。 我对此对象和按钮创建的图像只有问题,单击后不可见,但在调整窗口大小后才可见。 我知道这与setVisibility(true)有关; 但我不确定在哪里使用它。
使用SwingUtilities.invokeLater()或EventQueue.invokeLater()确保EDT正确初始化。
使用重写的paintComponent()
方法代替paint()
class SuperPanel extends JPanel {
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
...
}
@Override
public Dimension getPreferredSize() {
return new Dimension(..., ...);
}
}
尽量避免使用null
布局,并根据我们的需要使用合适的布局。
请看一下如何使用各种布局管理器 ,这些管理器完全负责组件的定位和大小调整。
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