我有以下简单的例子；
public class TES extends JFrame {
private JPanel contentPane;
private JTextField textField;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
TES frame = new TES();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public TES() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 100, 100);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
textField = new JTextField();
textField.setColumns(10);
JButton btnNewButton = new JButton("New button");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
System.out.println("Before ");
textField.setText("Before");
Thread.sleep(4000);
} catch (InterruptedException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
textField.setText("After");
}
});
GroupLayout gl_contentPane = new GroupLayout(contentPane);
gl_contentPane.setHorizontalGroup(
gl_contentPane.createParallelGroup(Alignment.TRAILING)
.addGroup(gl_contentPane.createSequentialGroup()
.addContainerGap()
.addComponent(btnNewButton)
.addContainerGap(GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addGroup(gl_contentPane.createSequentialGroup()
.addContainerGap(GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(textField, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
.addContainerGap())
);
gl_contentPane.setVerticalGroup(
gl_contentPane.createParallelGroup(Alignment.LEADING)
.addGroup(gl_contentPane.createSequentialGroup()
.addComponent(textField, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
.addPreferredGap(ComponentPlacement.RELATED, 61, Short.MAX_VALUE)
.addComponent(btnNewButton)
.addContainerGap())
);
contentPane.setLayout(gl_contentPane);
}
}
textField.settext("Before") 行没有被执行。
try {
System.out.println("Before ");
textField.setText("Before");
Thread.sleep(4000);
} catch (InterruptedException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
textField.setText("After");
}
System.out.println("Before ") 行虽然被执行。我输入 thread.sleep(4000) 只是为了暂停，这样我就可以在 JtextField 中看到“之前”和“之后”文本。在我的原始代码中，我在那个地方运行另一个类；
try {
System.out.println("Before ");
textField.setText("Before");
Functions.dbSet();
} catch (InterruptedException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
textField.setText("After");
}
所以主要问题是 textField.setText("Before"); 行没有被执行。