Java change JTextField size inside a GridLayout

问题

I have a GridLayout(3,2) as follows with 2 JLabels, 2 JTextFields and a JButton. I add them as shown in the pic or code. Everything is just fine but the JTextField size is too big and I want it to be as shown by the red lines I've drawed. I have tried saying jtf3.setPreferredSize( new Dimension( x, y ) ); but it didn't change the dimension at all. One other solution was to make the GridLayout somewhat GridLayout(3,2,1,50) for example (by adding 50) but that moves the JLabels way top too... I just want to be exactly as shown in the pic... Any ideas? Thanks a lot

JPanel copying_panel = new JPanel();
copying_panel.setLayout(new GridLayout(3, 2));
copying_panel.setBackground(new Color(200, 221, 242));
JLabel jl4 = new JLabel("From:", SwingConstants.CENTER);
JTextField jtf3 = new JTextField();
JLabel jl5 = new JLabel("To:", SwingConstants.CENTER);
JTextField jtf4 = new JTextField();
JLabel jl6 = new JLabel();
JButton jb2 = new JButton("Go");

copying_panel.add(jl4);
copying_panel.add(jtf3);
copying_panel.add(jl5);
copying_panel.add(jtf4);
copying_panel.add(jl6);
copying_panel.add(jb2);

回答1:

That's how GridLayout works, it provides equal space to all the components. Instead, consider using a GridBagLayout instead.

See How to Use GridBagLayout for more details

JPanel copying_panel = new JPanel();
copying_panel.setLayout(new GridBagLayout());
copying_panel.setBackground(new Color(200, 221, 242));
JLabel jl4 = new JLabel("From:", SwingConstants.CENTER);
JTextField jtf3 = new JTextField(10);
JLabel jl5 = new JLabel("To:", SwingConstants.CENTER);
JTextField jtf4 = new JTextField(10);
JButton jb2 = new JButton("Go");

GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
copying_panel.add(jl4, gbc);

gbc.gridy++;
copying_panel.add(jl5, gbc);

gbc.anchor = GridBagConstraints.EAST;
gbc.fill = GridBagConstraints.HORIZONTAL;
gbc.gridx++;
gbc.gridy = 0;
copying_panel.add(jtf3, gbc);

gbc.gridy++;
copying_panel.add(jtf4, gbc);

gbc.anchor = GridBagConstraints.WEST;
gbc.fill = GridBagConstraints.NONE;
gbc.gridy++;
copying_panel.add(jb2, gbc);

来源：https://stackoverflow.com/questions/27391049/java-change-jtextfield-size-inside-a-gridlayout