public class Grouplayout implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Grouplayout());
}
@Override
public void run() {
JFrame jFrame = new JFrame();
GroupLayout layout = new GroupLayout(jFrame.getContentPane());
jFrame.getContentPane().setLayout(layout);
layout.setAutoCreateGaps(true);
layout.setAutoCreateContainerGaps(true);
JLabel jLabel1 = new JLabel("a");
JLabel jLabel2 = new JLabel("b");
JLabel jLabel3 = new JLabel("c");
JLabel jLabel4 = new JLabel("d");
layout.setVerticalGroup(
layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(jLabel2))
.addGroup(layout.createParallelGroup(GroupLayout.Alignment.BASELINE)
.addComponent(jLabel3)
.addComponent(jLabel4)));
jFrame.pack();
jFrame.setVisible(true);
}
}
我正在尝试运行它,但出现以下异常:
线程“AWT-EventQueue-0”中的异常 java.lang.IllegalStateException: javax.swing.JLabel[,0,0,0x0,invalid,alignmentX=0.0,alignmentY=0.0,border=,flags=8388608,maximumSize=,minimumSize =,preferredSize=,defaultIcon=,disabledIcon=,horizontalAlignment=LEADING,horizontalTextPosition=TRAILING,iconTextGap=4,labelFor=,text=a,verticalAlignment=CENTER,verticalTextPosition=CENTER] 未附加到水平组
有什么问题?我该如何解决?