我已經爲我的Netbeans生成的GUI添加了一個JPanel,並添加了一個覆蓋paintComponent
的JPanel BoxThing
並繪製一個小紅框,但它不顯示,paintComponent
甚至不會被調用。如果我實例化我自己的JFrame並將一個包含BoxThing的JPanel放入其中,它可以正常工作。在Netbeans GUI中覆蓋paintComponent
我見過這個問題,在隨機論壇上問了幾個問題,人們不回答這個問題,而是指向custom painting tutorial,這顯然沒有幫助。
我先試用Netbeans 5.5,然後切換到NetBeans 6.8,同樣的問題。
Main.java
package MadProGUI9000;
public class Main extends javax.swing.JFrame {
/** Creates new form Main */
public Main() {
initComponents();
panel.add(new BoxThing());
}
/** 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">
private void initComponents() {
panel = new javax.swing.JPanel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
panel.setBorder(javax.swing.BorderFactory.createLineBorder(new java.awt.Color(0, 0, 0)));
javax.swing.GroupLayout panelLayout = new javax.swing.GroupLayout(panel);
panel.setLayout(panelLayout);
panelLayout.setHorizontalGroup(
panelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 260, Short.MAX_VALUE)
);
panelLayout.setVerticalGroup(
panelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 185, Short.MAX_VALUE)
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(69, 69, 69)
.addComponent(panel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(69, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(45, 45, 45)
.addComponent(panel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(68, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Main().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JPanel panel;
// End of variables declaration
}
BoxThing.java
package MadProGUI9000;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
/**
* A component with a red box in the center.
*/
public class BoxThing extends JPanel {
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
Dimension size = getSize();
int rX = (size.width - 5)/2;
int rY = (size.height - 5)/2;
g.setColor(Color.RED);
g2.fillRect(rX, rY, 5, 5);
}
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame("BoxThing demo");
JPanel panel = new JPanel();
frame.add(panel);
panel.add(new BoxThing());
frame.setVisible(true);
panel.setPreferredSize(new Dimension(100, 100));
frame.pack();
}
});
}
}
正如你所看到的,如果你只是運行BoxThing.java
的main
它的工作原理。如果你運行Netbeans GUI,它不會工作。那麼,如何將自定義組件添加到Netbeans生成的Swing GUI?
您是否嘗試在NetBeans生成的版本中使用FlowLayout? – 2010-06-15 15:21:52
@mmyers:我將'panel'的佈局更改爲FlowLayout,並修復了它,結果表明它之前使用了GroupLayout,我想這可以解釋它。 – 2010-06-15 15:33:21
我在這臺機器上沒有Netbeans,或者我自己嘗試。它一定是一個佈局問題,但我無法從代碼中知道它爲什麼可能被隱藏起來。 – 2010-06-15 15:47:29