[英]Unusual behavior for the same swing code in netbeans
我有两个几乎相似的代码。
代码一
JFrame pFrame=new NetBeansFrame();
JPanel myPanel=new myPanel();
pFrame.add(myPanel);
Dimension windowDim=myPanel.getSize();
pFrame.pack();
pFrame.getContentPane().setSize(windowDim.width-100,windowDim.height-50);
pFrame.setVisible(true);
守则二
JFrame pFrame=new JFrame();
JPanel myPanel=new myPanel();
pFrame.add(myPanel);
Dimension windowDim=myPanel.getSize();
pFrame.pack();
pFrame.getContentPane().setSize(windowDim.width-100,windowDim.height-50);
pFrame.setVisible(true);
在代码I中,NetBeansFrame是我使用netbeans-> Jframe创建的框架,并将其命名为NetBeansFrame。它不包含任何内容。我使用codeI将面板添加到其中。
NetBeansFrame.java
public class NetBeansFrame extends javax.swing.JFrame {
public NetBeansFrame() {
initComponents();
}
/** 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() {
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 407, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 429, Short.MAX_VALUE)
);
pack();
}// </editor-fold>
/**
* @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 ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(NetBeansFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(NetBeansFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(NetBeansFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(NetBeansFrame.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 NetBeansFrame().setVisible(true);
}
});
}
// Variables declaration - do not modify
// End of variables declaration
}
在代码II中,我从JFrame创建一个框架。逻辑上这两个代码是等效的。
但是在执行代码I时,该面板不会出现在netbeansFrame中,而对于代码II,该面板会出现。
因此,我想知道对于几乎相同的代码,这种异常行为可能是什么原因?
Dimension windowDim=myPanel.getSize();
仅返回Dimension[0, 0]
,因为从返回了Dimension
已经可见的容器(在您的情况下为组件JPanel
)
在调用pack();
然后pFrame.getContentPane().setSize(windowDim.width-100,windowDim.height-50);
返回的Dimension[-100, -50]
您可以
如果JPanel
为空,则返回其PreferredSize
如果JPanel
不为空,则其JComponents
返回PreferredSize
您可以尝试删除/禁用代码行pFrame.getContentPane().setSize(windowDim.width-100,windowDim.height-50);
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.