我正在使用一个GUI，其中有一个300X300 Jframe，一个具有相同大小（作为背景）的JPanel，其布局是BorderLayout，内部有三个JPanel。在其中一个JPanels中，还有另一个JPanel，它具有我创建的CustomPanelUI，但是在绘制JPanel时，颜色会发生变化。
CustomPanelUI：
import java.awt.Color;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JComponent;
import javax.swing.plaf.basic.BasicPanelUI;
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
/**
*
* @author Ionut Cicio
*/
public class CustomPanelUI extends BasicPanelUI{
Color firstColor;
Color secondColor;
CustomPanelUI(Color firstColor, Color secondColor){
this.firstColor = firstColor;
this.secondColor = secondColor;
}
@Override
public void update(Graphics g, JComponent c) {
if (c.isOpaque()) {
Graphics2D g2 = (Graphics2D) g;
g2.setPaint(new GradientPaint(
c.getX(),
c.getY() + c.getHeight() / 2,
firstColor,
c.getX() + c.getWidth(),
c.getY() + c.getHeight() / 2,
secondColor));
g2.fillRect(c.getX(), c.getY(), c.getWidth(), c.getHeight());
g2.drawRect(c.getX(), c.getY(), c.getWidth(), c.getHeight());
}
paint(g, c);
}
}
大型机：
import java.awt.Color;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
/**
*
* @author Utente
*/
public class BaseConverterGUI extends javax.swing.JFrame {
BufferedImage frameIcon = null; //Make Icon thicker
/**
* Creates new form BaseConverterGUI
*/
public BaseConverterGUI() {
try {
frameIcon = ImageIO.read(new File("C:\\Users\\Utente\\Desktop\\BaseConverter\\data\\Icon.png"));
} catch(IOException e){
System.out.println(e);
}
initComponents();
background.setUI(new CustomPanelUI(new Color(10, 36, 106), background.getBackground()));
inputBackground.setUI(new CustomPanelUI(inputBackground.getBackground(), new Color(255, 255, 255)));
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">//GEN-BEGIN:initComponents
private void initComponents() {
background = new javax.swing.JPanel();
output = new javax.swing.JPanel();
input = new javax.swing.JPanel();
inputBackground = new javax.swing.JPanel();
analysis = new javax.swing.JPanel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setTitle(" Base Converter");
setIconImage(frameIcon);
setName("MainFrame"); // NOI18N
setPreferredSize(new java.awt.Dimension(300, 300));
setResizable(false);
setSize(new java.awt.Dimension(300, 300));
background.setBackground(new java.awt.Color(165, 201, 239));
background.setBorder(javax.swing.BorderFactory.createLineBorder(new java.awt.Color(212, 208, 200)));
background.setForeground(new java.awt.Color(255, 255, 255));
background.setLayout(new java.awt.BorderLayout());
output.setBackground(new java.awt.Color(0, 0, 0));
output.setOpaque(false);
javax.swing.GroupLayout outputLayout = new javax.swing.GroupLayout(output);
output.setLayout(outputLayout);
outputLayout.setHorizontalGroup(
outputLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 298, Short.MAX_VALUE)
);
outputLayout.setVerticalGroup(
outputLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 100, Short.MAX_VALUE)
);
background.add(output, java.awt.BorderLayout.PAGE_END);
input.setBackground(new java.awt.Color(0, 0, 0));
input.setOpaque(false);
inputBackground.setBackground(new java.awt.Color(23, 123, 123));
inputBackground.setBorder(javax.swing.BorderFactory.createLineBorder(new java.awt.Color(255, 255, 255), 2));
javax.swing.GroupLayout inputBackgroundLayout = new javax.swing.GroupLayout(inputBackground);
inputBackground.setLayout(inputBackgroundLayout);
inputBackgroundLayout.setHorizontalGroup(
inputBackgroundLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 86, Short.MAX_VALUE)
);
inputBackgroundLayout.setVerticalGroup(
inputBackgroundLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 63, Short.MAX_VALUE)
);
javax.swing.GroupLayout inputLayout = new javax.swing.GroupLayout(input);
input.setLayout(inputLayout);
inputLayout.setHorizontalGroup(
inputLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(inputLayout.createSequentialGroup()
.addGap(77, 77, 77)
.addComponent(inputBackground, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(131, Short.MAX_VALUE))
);
inputLayout.setVerticalGroup(
inputLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(inputLayout.createSequentialGroup()
.addContainerGap()
.addComponent(inputBackground, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addContainerGap())
);
background.add(input, java.awt.BorderLayout.PAGE_START);
analysis.setBackground(new java.awt.Color(0, 0, 0));
analysis.setOpaque(false);
javax.swing.GroupLayout analysisLayout = new javax.swing.GroupLayout(analysis);
analysis.setLayout(analysisLayout);
analysisLayout.setHorizontalGroup(
analysisLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 298, Short.MAX_VALUE)
);
analysisLayout.setVerticalGroup(
analysisLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 107, Short.MAX_VALUE)
);
background.add(analysis, java.awt.BorderLayout.CENTER);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(background, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(background, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
pack();
}// </editor-fold>//GEN-END:initComponents
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Metal".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(BaseConverterGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(BaseConverterGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(BaseConverterGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(BaseConverterGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new BaseConverterGUI().setVisible(true);
}
});
}
// Variables declaration - do not modify//GEN-BEGIN:variables
private javax.swing.JPanel analysis;
private javax.swing.JPanel background;
private javax.swing.JPanel input;
private javax.swing.JPanel inputBackground;
private javax.swing.JPanel output;
// End of variables declaration//GEN-END:variables
}
最佳答案
Graphics上下文会自动转换为组件坐标空间，这意味着左上角始终为0x0。
您的代码将添加一个额外的偏移量（组件位置在其父坐标空间内），这使绘画从另一个位置开始。
而是使用0x0作为绘画的起点。
例如...
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.EmptyBorder;
import javax.swing.plaf.basic.BasicPanelUI;
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);
JPanel content = new JPanel(new GridBagLayout());
// This will offset the content, so we can see that the code is working
content.setBorder(new EmptyBorder(10, 10, 10, 10));
frame.setContentPane(content);
// Add multiple instances so we can see that the code is working
frame.add(new TestPane());
frame.add(new TestPane());
frame.add(new TestPane());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setUI(new CustomPanelUI(Color.RED, Color.BLUE));
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
public class CustomPanelUI extends BasicPanelUI {
Color firstColor;
Color secondColor;
CustomPanelUI(Color firstColor, Color secondColor) {
this.firstColor = firstColor;
this.secondColor = secondColor;
}
@Override
public void update(Graphics g, JComponent c) {
if (c.isOpaque()) {
Graphics2D g2 = (Graphics2D) g;
g2.setPaint(new GradientPaint(
0,
c.getHeight() / 2,
firstColor,
c.getWidth(),
c.getHeight() / 2,
secondColor));
g2.fillRect(0, 0, c.getWidth(), c.getHeight());
g2.drawRect(0, 0, c.getWidth(), c.getHeight());
}
paint(g, c);
}
}
}
关于java - Java Swing 渐变漆ISSUE，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/54203443/