Java 如何在JPanel上放置图形?
我在向JPanel添加图形时遇到问题。如果我更改panel.add(newgraphics())中的行;添加(新图形());并且不要将JPanel添加到JFrame,黑色矩形将显示在JFrame上。我就是不能让黑色矩形出现在JPannel上,我想知道是否有人能帮我解决这个问题Java 如何在JPanel上放置图形?,java,swing,graphics,jframe,jpanel,Java,Swing,Graphics,Jframe,Jpanel,我在向JPanel添加图形时遇到问题。如果我更改panel.add(newgraphics())中的行;添加(新图形());并且不要将JPanel添加到JFrame,黑色矩形将显示在JFrame上。我就是不能让黑色矩形出现在JPannel上,我想知道是否有人能帮我解决这个问题 import java.awt.*; import java.awt.event.*; import javax.swing.*; public class Catch{ public class graphics
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Catch{
public class graphics extends JComponent{
public void paintComponent(Graphics g){
super.paintComponents(g);
g.fillRect(200, 62, 30, 10);
}
}
public void createGUI(){
final JFrame frame = new JFrame();
JPanel panel = new JPanel();
frame.setSize(500,500);
frame.addMouseListener(new MouseAdapter(){
public void mouseClicked(MouseEvent e) {
System.out.println(e.getPoint().getX());
System.out.println(e.getPoint().getY());
}
});
panel.add(new graphics());
frame.add(panel);
frame.setVisible(true);
frame.setDefaultCloseOperation(frame.DISPOSE_ON_CLOSE);
}
public static void main(String[] args){
Catch GUI= new Catch();
GUI.createGUI();
}
}
自定义组件为0x0 px
import java.awt.*;
import javax.swing.*;
public class Catch {
public class MyGraphics extends JComponent {
private static final long serialVersionUID = 1L;
MyGraphics() {
setPreferredSize(new Dimension(500, 100));
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.fillRect(200, 62, 30, 10);
}
}
public void createGUI() {
final JFrame frame = new JFrame();
JPanel panel = new JPanel();
panel.add(new MyGraphics());
frame.add(panel);
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
Catch GUI = new Catch();
GUI.createGUI();
}
});
}
}
以下是您可以看到的内容:
import javax.swing.*;
import java.awt.*;
public class GraphicsOnJPanel extends JFrame
{
public GraphicsOnJPanel ()
{
setSize (Toolkit.getDefaultToolkit ().getScreenSize ());
setResizable (false);
setContentPane (new JPanel ()
{
public void paint (Graphics g)
{
g.setColor (Color.RED);
g.fillRect (100, 100, 100, 100);
}
}
);
setVisible (true);
}
public static void main (String args[])
{
new GraphicsOnJPanel ();
}
}
也许这很有用?
图形
不是添加到GUI元素中的东西。基本上,每个扩展JComponent
的组件都有一个paint()
方法,该方法自动传递到Graphics g
对象中。然后参照该对象在当前元素上绘制图形。我试着看了看,但还是有点困惑。你能给我举个例子吗?对于如何将其直接添加到框架中,而不是面板中,我也有点困惑。“Graphics”和“Graphics”是不同的类,@Jon提到的内容仅部分适用。你试过设置布局管理器吗?是的,我明白,那对我来说是个糟糕的名字选择。哇!非常感谢你的帮助!!