Preventing Swing Components from Becoming Off-Centered when using GridBagLayout in Java

Question

I'm attempting to make a simple GUI using Swing components in Java. However, some of the components are off-center due to other components' sizes. I'm using GridBagConstraints.CENTER to center these components, but it seems to keep them centered only relative to the Grid cell that they are contained within.

The specific issue I have is pictured below. I need the JTextField next to "File Name:" to be a certain length. But when I make it this certain length, it causes other components in other rows to become off-centered. The only way to maintain all the components being centered seems to be to have both JTextFields being the same length.

I'm a bit new to Swing and Java GUI in general, so I'm probably missing some basic concept, but I haven't found an answer to this particular question from my searches yet.

Image Showing the Components becoming Off-Centered when the JTextField length changes

>

//Initialize global Swing objects
JFrame frame = new JFrame("Game Server V2.0 build 019827427");
JPanel panel = new JPanel();
JButton runButton = new JButton("Start Server");
JButton stopButton = new JButton("Stop Server");
JButton sendButton = new JButton("Send File");
JTextField portField = new JTextField("999", 5);
JTextField fileField = new JTextField("fileToSend.txt", 14);
JLabel portLabel = new JLabel("Port:  ");
JLabel fileLabel = new JLabel("File Name:  ");
JLabel statusLabel = new JLabel("Status: Disconnected");

public void run(){

    //Set layout and constraints
    panel.setLayout(new GridBagLayout()); 
    GridBagConstraints gc = new GridBagConstraints();

    //Add Swing components to panel using GridBagLayout with the GridBagConstraints we've specified
    gc.weightx = 0.5;
    gc.weighty = 0.5;

    gc.gridx = 0;
    gc.gridy = 0;
    gc.gridwidth = 1;
    gc.anchor = GridBagConstraints.LINE_END;
    panel.add(portLabel, gc);

    gc.gridx = 1;
    gc.gridy = 0;
    gc.gridwidth = 1;
    gc.anchor = GridBagConstraints.LINE_START;
    panel.add(portField, gc); 

    gc.gridx = 0;
    gc.gridy = 1;
    gc.gridwidth = 1;
    gc.anchor = GridBagConstraints.LINE_END;
    panel.add(fileLabel, gc);

    gc.gridx = 1;
    gc.gridy = 1;
    gc.gridwidth = 1;
    gc.anchor = GridBagConstraints.LINE_START;
    panel.add(fileField, gc);

    gc.gridx = 0;
    gc.gridy = 2;
    gc.gridwidth = 2;
    gc.anchor = GridBagConstraints.CENTER;
    panel.add(sendButton, gc);

    gc.gridx = 0;
    gc.gridy = 3;
    gc.gridwidth = 1;
    panel.add(runButton, gc);

    gc.gridx = 1;
    gc.gridy = 3;
    gc.gridwidth = 1;
    panel.add(stopButton, gc);

    gc.gridx = 0;
    gc.gridy = 4;
    gc.gridwidth = 2;
    panel.add(statusLabel, gc);

    frame.add(panel);
    frame.setSize(480, 280);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);

}

Answer 1

I guess what I'm really wanting is for both columns of cells to be of equal width,

So then you should have the "Start" and "Stop" buttons in their own column. Then should have a weightx of 1.0 to allow then to expand. They should be centered.

Note: they won't be exactly centered because the width of the start button will slightly larger than the stop button so it will have a few extra pixels of space.

For all the other rows of data you would need to add a single component to each row. Each component would then need a gridwidth of 2. Each component would be centered. Since the first two rows contain two components you would need to create a panel and add the components to the panel. Then you add the panel to the panel using the GridBagLayout.