我有一個問題，因為我試圖讓兩個 JCheckbox 影像都被選中和到目前為止沒有被選中，我能夠從 UIManager 獲得圖示，但不幸的是它沒有勾選版本？我見過有畫那些圖示的畫家，但如果我運行下面的代碼，它會給我 NPE。
p = (Painter) UIManager.get("CheckBox[Enabled].iconPainter");
BufferedImage selected = new BufferedImage( 20, 20, BufferedImage.TYPE_INT_ARGB ) ;
p.paint((Graphics2D) selected.getGraphics(), null, 20, 20);
任何人都可以幫我解決這個問題嗎？
編輯：
基本上 p 在 get 方法之后為空。
堆：
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at addlayer.AddLayerUI.initOwn(AddLayerUI.java:47)
at addlayer.AddLayerUI.<init>(AddLayerUI.java:28)
at addlayer.AddLayerUI$1.run(AddLayerUI.java:136)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
代碼：
package addlayer;
import java.awt.Graphics2D;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import javax.swing.Icon;
import javax.swing.Painter;
import javax.swing.UIManager;
public class AddLayerUI extends javax.swing.JFrame {
public AddLayerUI() {
initComponents();
initOwn();
}
private void initOwn(){
Icon icn ;
icn = UIManager.getIcon("CheckBox.icon") ; //Works but gives only unchecked version of the check box, i need checked as well
Painter p;
p = (Painter) UIManager.get("CheckBox[Selected].iconPainter"); // returns null
BufferedImage selected = new BufferedImage( 20, 20, BufferedImage.TYPE_INT_ARGB ) ;
p.paint((Graphics2D) selected.getGraphics(), null, 20, 20);
};
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setTitle("AddLayer - TatukGIS DK11 sample");
setIconImage(Toolkit.getDefaultToolkit().getImage(getClass().getResource("/resources/icon.png")));
setSize(new java.awt.Dimension(800, 600));
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 800, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 601, Short.MAX_VALUE)
);
pack();
}// </editor-fold>
public static void main(String args[]) {
/* Set the Windows look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Windows".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(AddLayerUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(AddLayerUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(AddLayerUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(AddLayerUI.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 AddLayerUI().setVisible(true);
}
});
}
// Variables declaration - do not modify
// End of variables declaration
}
uj5u.com熱心網友回復：
此示例將使用 UI 來繪制處于不同狀態的按鈕。
（圖片有錯誤，左上角不要勾選。）
import javax.swing.*;
import javax.swing.plaf.*;
import javax.swing.plaf.basic.*;
import java.awt.image.*;
import java.awt.*;
public class Icp{
public static void main(String[] args){
JCheckBox canon = new JCheckBox();
Dimension d = canon.getPreferredSize();
int w = (int)d.getWidth();
int h = (int)d.getHeight();
canon.setBounds(0, 0, w, h);
BasicToggleButtonUI ui = (BasicToggleButtonUI)UIManager.getUI( canon );
BufferedImage img = new BufferedImage(2*w, 2*h, BufferedImage.TYPE_INT_ARGB);
Graphics g = img.getGraphics();
ui.paint(g, canon);
g.translate( w, 0);
canon.setSelected(true);
ui.paint(g, canon);
g.translate(-w, h);
canon.setEnabled(false);
canon.setSelected(false);
ui.paint(g, canon);
g.translate(w, 0);
canon.setSelected(true);
ui.paint(g, canon);
g.dispose();
ImageIcon ico = new ImageIcon(img);
JFrame frame = new JFrame();
JLabel icn = new JLabel( ico );
frame.add(icn);
frame.pack();
frame.setVisible(true);
System.out.println( ui );
}
}
我轉換為 BasicToggleButtonUI 因為它有一個圖示方法，但它受到保護。
轉載請註明出處，本文鏈接：https://www.uj5u.com/shujuku/457796.html
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