如何使用GridBagLayout强制JPanel使用JFrame进行调整

Question

我需要menuPanel的组件在框架展开时展开。 MenuPanel使用的是GridBayLayout，我用面板的填充和重量值来修饰，但是没有任何东西看起来会导致组件随着框架调整大小。

我怀疑我在显示类中添加menuPanel的方式有问题。此外，我还尝试将设置布局设置为TanksApplication，但这也不起作用。我想，我不了解一些基本的东西。

主要应用

public class TanksApplication extends JFrame{ 

     public TanksApplication(){ 
      super("Tanks"); 
     } 

     public static void main (String args[]){ 
      Display display = new Display(); 
      TanksApplication frame = new TanksApplication(); 
      frame.add(display); 
      frame.setSize(600,425); 
      frame.setVisible(true); 
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
      frame.setLocationRelativeTo(null); 
     } 
    } 

Display类

public class Display extends JPanel{  
    public Display(){ 
     menuPanel = new JPanel(new GridBagLayout()); 
     GridBagConstraints con = new GridBagConstraints(); 

     mainMenuImageP = new JPanel(); 
     mainMenuImageP.setBackground(Color.BLACK); 
     con.fill = GridBagConstraints.BOTH; 
     con.gridy = 0; 
     con.gridx = 0; 
     con.gridwidth = 2; 
     con.weightx = 0.5; 
     con.weighty = 0.5; 
     con.anchor = GridBagConstraints.CENTER; 
     con.ipadx = 400; 
     con.ipady = 300; 
     con.insets = new Insets(0,20,0,20); 
     menuPanel.add(mainMenuImageP, con); 

     newGameB = new JButton("New Game"); 
     con.fill = GridBagConstraints.HORIZONTAL; 
     con.gridy = 1; 
     con.gridx = 0; 
     con.gridwidth = 1; 
     con.weightx = 0.5; 
     con.weighty = 0.5; 
     con.anchor = GridBagConstraints.CENTER; 
     con.ipadx = 0; 
     con.ipady = 0; 
     con.insets = new Insets(10,10,10,10); 
     menuPanel.add(newGameB, con); 

     loadGameB = new JButton("Load Game"); 
     con.fill = GridBagConstraints.HORIZONTAL; 
     con.gridy = 1; 
     con.gridx = 1; 
     con.gridwidth = 1; 
     con.weightx = 0.5; 
     con.weighty = 0.5; 
     con.anchor = GridBagConstraints.CENTER; 
     con.ipadx = 0; 
     con.ipady = 0; 
     con.insets = new Insets(10,10,10,10); 
     menuPanel.add(loadGameB, con); 

     add(menuPanel); 
    } 

Answer 1

你的问题是，你正在使用menuPanel到显示的JPanel添加你的GridBagLayout的，后者的使用JPanel的默认的FlowLayout。 FlowLayout不会调整添加到其中的组件的大小。解决方案：获取menuPanel的rid，并使用Display JPanel。给它一个GridBagLayout并将组件添加到它。

所以有你的显示器的构造函数中

setLayout(new GridBagLayout()); 

删除JPanel menuPanel = new JPanel();以及任何你有menuPane.add(...);，将其更改为简单add(...);

例如，

public class Display extends JPanel{  
    public Display(){ 
     // !! menuPanel = new JPanel(new GridBagLayout()); 
     GridBagConstraints con = new GridBagConstraints(); 

     mainMenuImageP = new JPanel(); 
     mainMenuImageP.setBackground(Color.BLACK); 
     con.fill = GridBagConstraints.BOTH; 
     con.gridy = 0; 
     con.gridx = 0; 
     con.gridwidth = 2; 
     con.weightx = 0.5; 
     con.weighty = 0.5; 
     con.anchor = GridBagConstraints.CENTER; 
     con.ipadx = 400; 
     con.ipady = 300; 
     con.insets = new Insets(0,20,0,20); 
     // !! menuPanel.add(mainMenuImageP, con); 
     add(mainMenuImageP, con); // !! 

     newGameB = new JButton("New Game"); 
     con.fill = GridBagConstraints.HORIZONTAL; 
     con.gridy = 1; 
     con.gridx = 0; 
     con.gridwidth = 1; 
     con.weightx = 0.5; 
     con.weighty = 0.5; 
     con.anchor = GridBagConstraints.CENTER; 
     con.ipadx = 0; 
     con.ipady = 0; 
     con.insets = new Insets(10,10,10,10); 
     // !! menuPanel.add(newGameB, con); 
     add(newGameB, con); // !! 

     loadGameB = new JButton("Load Game"); 
     con.fill = GridBagConstraints.HORIZONTAL; 
     con.gridy = 1; 
     con.gridx = 1; 
     con.gridwidth = 1; 
     con.weightx = 0.5; 
     con.weighty = 0.5; 
     con.anchor = GridBagConstraints.CENTER; 
     con.ipadx = 0; 
     con.ipady = 0; 
     con.insets = new Insets(10,10,10,10); 
     // !! menuPanel.add(loadGameB, con); 
     add(loadGameB, con); // !! 

     // !! add(menuPanel); 
    } 

} 

注意，如果这样没有帮助，那么请考虑创建和发布一个minimal example program或SSCCE。