java-为什么我的JPanel与我的JFrame上的其他组件搞混了？
作者：互联网
所以我有一个JFrame,其中包含一个JPanel,其中包含一个JList组件.
然后,我的paintComponent()有另一个JPanel,它也返回一个尺寸.
但是,当我设置尺寸的大小时,它会尝试重新放置其他JPanel.
这是我的paintComponent()代码：
class drawOnPanel extends JPanel {
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2.setColor(Color.BLUE);
}
@Override
public Dimension getPreferredSize(){
return new Dimension(250, 250);
}
}
然后有我的JFrame,它调用drawOnPanel类：
public static void mainFrame() {
JFrame f = new MTGSAMPServerReference();
f.setTitle("MTG SAMP Server Reference Guide");
f.pack();
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new drawOnPanel());
f.setSize(330, 300);
f.setLocationRelativeTo(null);
}
然后我的JPanel上有我的JList：
public void MainMenu() {
JPanel controls = new JPanel(new BorderLayout(5,5));
final CardLayout cl = new CardLayout();
final JPanel panel = new JPanel(cl);
controls.add(panel);
this.getContentPane().setLayout(new FlowLayout(FlowLayout.LEADING));
list = new JList<Object>(mainMenu);
list.setVisibleRowCount(7);
select = new JButton("Select");
exit = new JButton("Exit");
select.addActionListener(this);
exit.addActionListener(this);
controls.add(new JScrollPane(list));
JPanel basePanel = new JPanel(new GridLayout(0, 1));
basePanel.add(select);
basePanel.add(exit);
controls.add(basePanel, BorderLayout.PAGE_END);
add(controls);
refreshFrame();
}
当我尝试在我的paintComponent()JPanel上绘制时,它会绘制,但是我指示的坐标没有正确绘制.
有人知道为什么会这样吗？
提前致谢！
编辑：这是我程序的一些屏幕截图.
这是我不包含drawOnPanel时程序的外观：
这是我包含drawOnPanel时程序的外观：
我只希望它在JList的右侧绘制,而不移动JList.如您所见,它将调整另一个JPanel.
任何和所有帮助表示赞赏！
编辑：这是我的SSCCE.
编辑：这是我的SSCCE代码：
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public final class SSCCE1 extends JFrame implements ActionListener {
private static final long serialVersionUID = 1L;
JList list;
JButton select;
JButton exit;
Object[]mainMenu = {"Value 1", "Value 2", "Value 3", "Value 4"};
public SSCCE1() {
MainMenu();
}
public void MainMenu() {
JPanel controls = new JPanel(new BorderLayout(5,5));
final CardLayout cl = new CardLayout();
final JPanel panel = new JPanel(cl);
controls.add(panel);
this.getContentPane().setLayout(new FlowLayout(FlowLayout.LEADING));
list = new JList<Object>(mainMenu);
list.setVisibleRowCount(7);
select = new JButton("Select");
exit = new JButton("Exit");
controls.add(new JScrollPane(list));
JPanel basePanel = new JPanel(new GridLayout(0, 1));
basePanel.add(select);
basePanel.add(exit);
controls.add(basePanel, BorderLayout.PAGE_END);
add(controls);
revalidate();
repaint();
SSCCE1.this.repaint();
}
public void createAndShowGUI() {
mainFrame();
SSCCE1.this.repaint();
}
public static void mainFrame() {
JFrame f = new SSCCE1();
f.setTitle("My SSCCE");
f.pack();
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new drawOnPanel()); // When this is uncommented, it messes with the other JPanel, but when commented, it works fine, but does not allow drawing on the other JFrame.
f.setExtendedState(JFrame.MAXIMIZED_BOTH);
f.setLocationRelativeTo(null);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
SSCCE1 gui = new SSCCE1();
gui.createAndShowGUI();
}
});
}
@Override
public void actionPerformed(ActionEvent ae) {
}
}
class drawOnPanel extends JPanel {
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2.setColor(Color.BLUE);
}
@Override
public Dimension getPreferredSize(){
return new Dimension(250, 250);
}
}
解决方法:
添加,打包和定位后,使setVisible()最后.完整示例见here和here.
f.add(…);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
附录：这是您的示例的一种变体,没有隐形面板.无需扩展JFrame的必要理由,只需创建一个并添加您的组件即可.
import java.awt.*;
import javax.swing.*;
/** @see https://stackoverflow.com/a/18038765/230513 */
public class SSCCE2 {
private JList list;
private JButton select;
private JButton exit;
private Object[] mainMenu = {"Value 1", "Value 2", "Value 3", "Value 4"};
public JPanel mainMenu() {
JPanel controls = new JPanel(new BorderLayout(5, 5));
list = new JList(mainMenu);
list.setVisibleRowCount(7);
select = new JButton("Select");
exit = new JButton("Exit");
controls.add(new JScrollPane(list));
JPanel basePanel = new JPanel(new GridLayout(0, 1));
basePanel.add(select);
basePanel.add(exit);
controls.add(basePanel, BorderLayout.PAGE_END);
return controls;
}
public void createAndShowGUI() {
JFrame f = new JFrame("My SSCCE");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new DrawOnPanel());
f.add(mainMenu(), BorderLayout.WEST);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
SSCCE2 gui = new SSCCE2();
gui.createAndShowGUI();
}
});
}
private static class DrawOnPanel extends JPanel {
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.BLUE);
g.fillRect(0, 0, getWidth(), getHeight());
}
@Override
public Dimension getPreferredSize() {
return new Dimension(250, 250);
}
}
}
标签：paintcomponent,swing,jpanel,dimension,java 来源： https://codeday.me/bug/20191122/2063786.html