Java 如何使用GridBagLayout

我有一个

JLabel

、一个

JButton

和一个

JTextField

；我需要将

JLabel

从

JFrame

原点放入单元格（0,0），然后放入

JTextField

（1,0），最后在第二行放入

JButton

（0,1）。但是，我的所有组件都放在同一行中，它们从左到右开始

我的代码：

public static  void initializeFrame(){
  GridBagLayout layout  = new GridBagLayout();
  // set frame layout      
  JFrame frame = new JFrame("JFrame Source Demo");
  frame.setSize(new Dimension(400,200));
  frame.setLayout(new GridBagLayout());
  GridBagConstraints c = new GridBagConstraints();
  c.fill = GridBagConstraints.HORIZONTAL;
  JPanel    topPanel = new JPanel();
  JLabel jlbempty = new JLabel("MacAddress");
  c.gridx = 0;
  c.gridy = 0;
  c.ipadx = 30;
  c.ipady = 10;
  topPanel.add(jlbempty,c);
  JTextField field1 = new JTextField();
  c.gridx = 1;   
  c.gridy = 0;
  c.ipadx = 30;
  c.ipady = 10;
  topPanel.add(field1,c);
  field1.setPreferredSize(new Dimension(150, 20));
  JButton jb = new JButton("Generation Mac");
  c.gridx = 0;
  c.gridy = 1;
  c.ipadx = 30;
  c.ipady = 10; 
  layout.setConstraints( jb, c ); // set constraints
  topPanel.add(field1,c); 
  topPanel.add(jb,c);
  frame.add(topPanel);
  frame.pack();
  frame.setVisible(true);
}

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我在代码中观察到的一些东西

• 将

  topPanel

  的布局设置为

  GridBagLayout

• 您正在调用

  topPanel.add（field1，c）两次
  

• 不要使用首选大小，而使用相对大小。只需将其交给布局管理器即可调整组件的大小

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阅读更多关于更清晰的信息，并找到示例代码

请阅读有关的其他属性的更多信息

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下面是带有内联注释的简化代码

GridBagConstraints c = new GridBagConstraints();
c.fill = GridBagConstraints.HORIZONTAL;
// c.insets=new Insets(5,5,5,5);   // margin outside the panel

JPanel topPanel = new JPanel(new GridBagLayout());

JLabel jlbempty = new JLabel("MacAddress");
c.gridx = 0;
c.gridy = 0;
// c.weightx=0.25;     // width 25% for 1st column
topPanel.add(jlbempty, c);

JTextField field1 = new JTextField();
c.gridx = 1;
c.gridy = 0;
// c.weightx=0.75;     // width 75% for 2nd column
topPanel.add(field1, c);

JButton jb = new JButton("Generation Mac");
c.gridx = 0;
c.gridy = 1;
//c.gridwidth = 2;    //SPAN to 2 columns if needed
// c.weightx=1.0;     // back to width 100%
topPanel.add(jb, c);