您好,我有以下类(class),我想要显示内容 (paintComponentor 具有来自paint 类的矩形的面板) 在我的 JFrame 中。我已经尝试找出如何实现这一目标 看看这个论坛上发布的不同例子,但是这个 对我没有帮助我需要简单的例子,比如框架内的面板 绘制组件或类似的东西以了解应该如何工作! 附:不要把我卡在树上,因为我是新手,只是问问题!!!
[我想要这样的东西][1]
package scp; import java.awt.*; import javax.swing.*; public class Panel extends JPanel { public Panel() { //this.setPreferredSize(new Dimension(200,200)); //panel = new Panel(); setVisible(true); setLayout(new FlowLayout()); setSize(200, 300); getRootPane(); } @Override public void paintComponent(Graphics g){ g.drawString("HEY",20,20); g.drawRect(200, 200, 200, 200); } } and package scp; import javax.swing.JFrame; import javax.swing.JButton; import java.awt.Color; import java.awt.FlowLayout; import java.awt.event.ActionListener; import java.awt.event.ActionEvent; import java.beans.EventHandler; public class Frame extends JFrame { JButton redButton; JButton blueButton; public Frame() { super("EventHandling"); setLayout(new FlowLayout()); redButton = new JButton("Red"); add(redButton); blueButton = new JButton("Blue"); add(blueButton); EventHandler h = new EventHandler(); redButton.addActionListener(h); blueButton.addActionListener(h); } private class EventHandler implements ActionListener { public void actionPerformed(ActionEvent e) { if (e.getSource()==redButton) getContentPane().setBackground(Color.RED); else if(e.getSource()==blueButton) getContentPane().setBackground(Color.BLUE); } } } and package scp; import javax.swing.JFrame; public class EventHandling { public static void main(String[] args) { Frame f = new Frame(); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setSize(800,600); f.setVisible(true); f.getContentPane().add(new Panel()); } }
[1]:/image/OJTrq.png
最佳答案
首先看一下:
这可能是我能做到的最简单的......
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
int width = getWidth() - 100;
int height = getHeight() - 100;
int x = (getWidth() - width) / 2;
int y = (getHeight() - height) / 2;
g2d.setColor(Color.RED);
g2d.drawRect(x, y, width, height);
g2d.dispose();
}
}
}
复合示例
此示例使用 outer
面板,该面板应用了空边框,这会推送 outer
面板边缘的内容。
内部面板(与上一个示例相比没有变化),应用了浅灰色边框以便您可以看到它,红色矩形仍然由面板 paintComponent
方法绘制。
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.EmptyBorder;
import javax.swing.border.LineBorder;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JPanel outer = new JPanel(new BorderLayout()) {
@Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
};
outer.setBorder(new EmptyBorder(50, 50, 50, 50));
TestPane tp = new TestPane();
tp.setBorder(new LineBorder(Color.LIGHT_GRAY));
outter.add(tp);
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(outer);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
int width = getWidth() - 100;
int height = getHeight() - 100;
int x = (getWidth() - width) / 2;
int y = (getHeight() - height) / 2;
g2d.setColor(Color.RED);
g2d.drawRect(x, y, width, height);
g2d.dispose();
}
}
}
关于java - JFrame、JPanel、paintComponent 如何,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/27179739/