Swing菜单项选择未在内容窗格中设置内容 [英] Swing menu item selection not setting content in the contentpane
问题描述
我有一个Swing JFrame，其中包含许多菜单项.下面的代码尝试但未在选择添加地址"菜单项时设置JFrame的内容.
I have a Swing JFrame, which has a bunch of menu items. The below code tries but fails to set the content of the JFrame on selection of 'Add Address' menu item.
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
frame.setVisible(true);
JMenuBar menuBar = new JMenuBar();
JMenu clientMenu = new JMenu("Client");
JMenuItem address = new JMenuItem("Add Address");
clientMenu.add(address);
menuBar.add(clientMenu);
address.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
setupAddressForm();
}
});
private void setupAddressForm() {
frame.getContentPane().removeAll();
JPanel infoPanel = new JPanel();
JLabel infoLabel = new JLabel();
infoLabel.setText("<html><B>Please enter the address below</B></html>");
infoPanel.add(infoLabel, SwingConstants.CENTER);
frame.getContentPane().add(infoPanel, BorderLayout.NORTH);
JPanel buttonPanel = new JPanel();
JButton submitButton = new JButton("Submit Address");
JButton resetButton = new JButton("Reset");
submitButton.setToolTipText("Submit");
resetButton.setToolTipText("Reset");
buttonPanel.add(submitButton);
buttonPanel.add(resetButton);
frame.getContentPane().add(buttonPanel, BorderLayout.SOUTH);
JPanel fieldPanel = new JPanel();
fieldPanel.setLayout(new GridLayout(10, 10));
JLabel houseNumberLabel = new JLabel("House Number",
SwingConstants.LEFT);
final JTextField houseNumberField = new JTextField(3);
JLabel streetNameLabel = new JLabel("Street Name", SwingConstants.LEFT);
final JTextField streetNameField = new JTextField(10);
JLabel localityLabel = new JLabel("Locality", SwingConstants.LEFT);
final JTextField localityField = new JTextField(10);
JLabel cityLabel = new JLabel("City", SwingConstants.LEFT);
final JTextField cityField = new JTextField(10);
JLabel stateLabel = new JLabel("State", SwingConstants.LEFT);
final JTextField stateField = new JTextField(10);
JLabel zipCodeLabel = new JLabel("Zip Code", SwingConstants.LEFT);
final JTextField zipCodeField = new JTextField(10);
fieldPanel.add(houseNumberLabel);
fieldPanel.add(houseNumberField);
fieldPanel.add(streetNameLabel);
fieldPanel.add(streetNameField);
fieldPanel.add(localityLabel);
fieldPanel.add(localityField);
fieldPanel.add(cityLabel);
fieldPanel.add(cityField);
fieldPanel.add(stateLabel);
fieldPanel.add(stateField);
fieldPanel.add(zipCodeLabel);
fieldPanel.add(zipCodeField);
frame.getContentPane().add(fieldPanel, BorderLayout.CENTER);
submitButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String houseNumber = houseNumberField.getText();
String street = streetNameField.getText();
String locality = localityField.getText();
String city = cityField.getText();
String state = stateField.getText();
String zipCode = zipCodeField.getText();
Address address = new Address();
if (!"".equals(houseNumber) && !"".equals(street)
&& !"".equals(locality) && !"".equals(city)
&& !"".equals(state) && !"".equals(zipCode)) {
address.setHouseNumber(houseNumber);
address.setStreetName(street);
address.setLocality(locality);
address.setState(state);
address.setZipCode(zipCode);
}
}
});
frame.getContentPane().doLayout();
frame.getContentPane().update(frame.getGraphics());
}
当我选择添加地址"菜单项时，框架只是空白.不是我所期望的.我使用断点进行调试，发现正在调用设置地址的方法. 我不知道为什么它不起作用.有人可以指出我在这里做错了什么吗吗?
When I select the 'Add Address' menu item, the frame just goes blank. Not what I expected. I debugged using break point and see that the method to setup the address is being called. I can't figure out why it doesn't work. Could any one point out if I am doing anything wrong here?
推荐答案
为什么要经历所有这些体操?相反，只需使用 CardLayout 即可以最少的混乱为您交换视图或大惊小怪.
Why go through all this gymnastics? Instead simply use a CardLayout to swap views for you with minimal mess or fuss.
还请注意，您在方法(A)的第一种方法或构造函数中创建的JFrame(没有说):
Also note that the JFrame you create on line (A) in either a method or constructor (you don't say):
JFrame frame = new JFrame(); // (A)
与(B)和(C)行使用的JFrame不同:
is not the same JFrame as the one used on lines (B) and (C):
private void setupAddressForm() {
frame.getContentPane().removeAll(); // (B)
JPanel infoPanel = new JPanel();
JLabel infoLabel = new JLabel();
infoLabel.setText("<html><B>Please enter the address below</B></html>");
infoPanel.add(infoLabel, SwingConstants.CENTER);
frame.getContentPane().add(infoPanel, BorderLayout.NORTH); // (C)
这是因为您在(A)行上声明了JFrame，因此它仅在该方法或构造函数中可见.
This is because you declare the JFrame on line (A) and so it is only visible within that method or constructor.
编辑1
另外，这是不对的:
Edit 1
Also, this is not right:
frame.getContentPane().doLayout();
frame.getContentPane().update(frame.getGraphics());
因为这不是您将新组件显示在Swing容器中的方式.相反，我会做这样的事情:
As that's not how you get new components to show in a container for Swing. Instead I'd do something like so:
JPanel contentPane = (JPanel) frame.getContentPane();
contentPane.revalidate();
contentPane.repaint();
但是，我仍然不会做任何事情，而是使用如上所述的CardLayout.
But again, I'd really do neither, and instead would use a CardLayout as noted above.
最后，如果这些建议中的任何一项都没有道理，请要求澄清.
Finally, if any of these recommendations don't make sense, please ask for clarification.
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