5

我有一个程序可以创建 2 个面板，然后在其中放置一个标签和两个按钮。标签设置为不可见setVisible(false)，然后添加两个按钮并打包框架。当我单击第一个按钮时，显示标签，，第二setVisible(true)个按钮再次隐藏它，setVisible(false)。当我单击每个按钮时，它们会移动以在标签隐藏时填充标签的空间，然后再次移动以避开显示的标签。我想阻止这种情况发生，即使标签被隐藏也让按钮保持在同一个地方。

这是代码：

public class MainFrame extends JFrame{
  public JLabel statusLabel;
  public JButton show;
  public JButton hide;  

  public MainFrame(){
    super("MagicLabel");

    JPanel topPanel = new JPanel();  //Create Top Panel
    statusLabel = new JLabel("");    //Init label
    statusLabel.setVisible(false);   //Hide label at startup
    topPanel.setSize(400, 150);      //Set the size of the panel, Doesn't work
    topPanel.add(statusLabel);       //Add label to panel

    JPanel middlePanel = new JPanel(); //Create Middle Panel
    show= new JButton("Show");       //Create show button
    hide= new JButton("Hide");       //Create hide button
    middlePanel.setSize(400, 50);    //Set the size of the panel, Doesn't work
    middlePanel.add(show);           //Add show button
    middlePanel.add(hide);           //Add hide button

    this.add(topPanel, "North");     //Add Top Panel to North
    this.add(middlePanel, "Center"); //Add Middle Panel to Center
    addActionListeners();            //void:adds action listeners to buttons
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    this.setBounds(100, 100, 512, 400);
    this.setPreferredSize(new Dimension(400,200)); //Set size of frame, Does work
    this.pack();
    this.setVisible(true);
  }

  public void animateInstall(boolean var0){  //Void to show and hide label from action listeners
    statusLabel.setVisible(var0);
    sendWorkingMessage("Boo!");
  }
  public void sendWorkingMessage(String message){ //Void to set text of label
    this.statusLabel.setForeground(new Color(225, 225, 0));
    this.statusLabel.setText(message);
  }

  void addActionListeners(){
    show.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            animateInstall(true);
        }
    });
    hide.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            animateInstall(false);
        }
    });
  }
4

4 回答 4

5 
this.setPreferredSize(new Dimension(400,200));
this.setMinimumSize(new Dimension(400,200));

So pack() cannot interfere.

于 2013-01-04T06:28:55.527 回答
2

使用CardLayout. 添加JLabel和空JPanel。而不是将其设置为可见/不可见，而是在必要时交换显示JLabel或的卡片JPanel。

于 2013-01-04T06:23:25.523 回答
2

Extending JFrame is not advisable, better extend JPanel put all your components inside and then add it to a JFrame

You need to learn how to use SwingUtilities.invokeLater(): See example how your should look like

You need to learn about Layout: Tutorial

Very dumb and easy approach in your code would be:

 this.statusLabel.setForeground(bgColor); //background color
 this.statusLabel.setText("           "); //some number of characters
于 2013-01-04T06:34:07.897 回答
2

By default for you frame you are using BorderLayout. You can try to have like:

this.add(topPanel, BorderLayout.NORTH);     //Add Top Panel to North
this.add(middlePanel, BorderLayout.SOUTH); //Add Middle Panel to South

rather than at center.

Or you can create an intermediate container panel for these 2 panels, or consider other layout managers like BoxLayout, etc

于 2013-01-04T06:34:58.970 回答