Java 在JFrame中创建JPanel,并使用paintComponent()方法绘制面板
这是我第一次使用java Swing,我不知道如何在Java 在JFrame中创建JPanel,并使用paintComponent()方法绘制面板,java,swing,jpanel,java-2d,Java,Swing,Jpanel,Java 2d,这是我第一次使用java Swing,我不知道如何在JSplitPane中的特定JPanel中绘制,我尝试创建一个新类来实现paintComponent方法,但它不能被重写。 有人能帮我吗 import javax.swing.*; import java.awt.*; public class SplitPane extends JPanel{ private JPanel mainPanel; private JPanel leftPanel; private J
JSplitPane
中的特定JPanel
中绘制,我尝试创建一个新类来实现paintComponent
方法,但它不能被重写。
有人能帮我吗
import javax.swing.*;
import java.awt.*;
public class SplitPane extends JPanel{
private JPanel mainPanel;
private JPanel leftPanel;
private JPanel rightPanel;
public SplitPane() {
}
public static void main(String args[]) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new SplitPane().createAndShowUI();
}
});
}
private void createAndShowUI() {
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500, 500);
initComponents(frame.getContentPane());
frame.setVisible(true);
}
private void initComponents(Container contentPane) {
mainPanel = new JPanel();
leftPanel = new JPanel();
rightPanel = new JPanel();
leftPanel.add(new JLabel("left"));
rightPanel.add(new JLabel("right"));
leftPanel.setPreferredSize(new Dimension(200, 40));
rightPanel.setPreferredSize(new Dimension(280, 400));
leftPanel.setBackground(Color.WHITE);
rightPanel.setBackground(Color.WHITE);
JSplitPane mainJsp = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT);
mainJsp.add(leftPanel, JSplitPane.TOP);
mainJsp.add(rightPanel, JSplitPane.BOTTOM);
mainJsp.setOneTouchExpandable(true);
mainJsp.setDividerLocation(150);
mainPanel.add(mainJsp);
contentPane.add(mainPanel);
leftPanel = new PaintPanel();
}
public class PaintPanel extends JPanel {
public PaintPanel() {
System.out.println("PaintPanel");
this.setLayout(new BorderLayout());
this.setPreferredSize(new Dimension(300, 300));
}
@Override
public void paintComponent(Graphics g) {
System.out.println("12345678");
super.paintComponent(g);
//g.setColor(Color.black);
g.drawRect(3, 3, 20, 20);
}
}
}
您从不向任何内容添加
PaintPanel
,例如
private void initComponents(Container contentPane) {
mainPanel = new JPanel();
leftPanel = new JPanel();
rightPanel = new JPanel();
leftPanel.add(new JLabel("left"));
rightPanel.add(new JLabel("right"));
leftPanel.setPreferredSize(new Dimension(200, 40));
rightPanel.setPreferredSize(new Dimension(280, 400));
leftPanel.setBackground(Color.WHITE);
rightPanel.setBackground(Color.WHITE);
JSplitPane mainJsp = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT);
mainJsp.add(leftPanel, JSplitPane.TOP);
mainJsp.add(rightPanel, JSplitPane.BOTTOM);
mainJsp.setOneTouchExpandable(true);
mainJsp.setDividerLocation(150);
mainPanel.add(mainJsp);
contentPane.add(mainPanel);
leftPanel = new PaintPanel();
// Just left hanging here, never added to anything...?
}
所以,如果我把它改成
private void initComponents(Container contentPane) {
mainPanel = new JPanel();
leftPanel = new PaintPanel();
rightPanel = new JPanel();
leftPanel.add(new JLabel("left"));
rightPanel.add(new JLabel("right"));
leftPanel.setPreferredSize(new Dimension(200, 40));
rightPanel.setPreferredSize(new Dimension(280, 400));
leftPanel.setBackground(Color.WHITE);
rightPanel.setBackground(Color.WHITE);
JSplitPane mainJsp = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT);
mainJsp.add(leftPanel, JSplitPane.TOP);
mainJsp.add(rightPanel, JSplitPane.BOTTOM);
mainJsp.setOneTouchExpandable(true);
mainJsp.setDividerLocation(150);
mainPanel.add(mainJsp);
contentPane.add(mainPanel);
//leftPanel = new PaintPanel();
}
它现在显示
public void paintComponent(Graphics g){
应该是public void paintComponent(Graphics g){
应该是public void paintComponent(Graphics g){super.paintComponent(g);..
另请参见(是)谢谢!它仍然不起作用,我在paintComponent函数中使用system.out.print,但控制台中没有打印输出,因此我认为此函数不会被重写。您从未将面板添加到任何容器中。没有添加(middleRightPanel)之类的行要更快地获得更好的帮助,请发布or。请注意,MCVE应该包括import
语句和main(String[])
来运行它。