javaswinguser-interfacelayout-managernull-layout-manager

JFrame & JPanel sizing issue

I am attempting to code a JFrame containing a JPanel. Within the JPanel is an array of JTextField's. So, my GUI looks like:-

enter image description here

I am not using a layout manager, and have set this to null for the JFrame and the JPanel. I am sizing these components by hand.

You can see that the right hand portion of the JPanel is chopped off, even though I have used the same sizing as the containing JFrame.

The code appears as below:-

enter image description here

I have calculated the required width of the JPanel by multiplying the number of columns in the JTextField array by the width of the JTextField. Aside from that would need to be added the width of each gap between the JTextFields (there would be (columnNumber - 1) of them), as well as the two border gaps.

I have done this, yet the right hand side border gap is chopped off, as you can see from the diagram.

If I add some random amount to the panelWidth, then you can see the right hand gap there, but my question is what am I missing here? This ought to work surely, if the JFrame side and the JPanel size are identical, which they are as I have also printed them both out, and the print outs give the same number.

Jeremy

Solution

  • I want for any combination of row/column values to allow a constant vertical & horizontal distance between each JTextField, and for each of those text fields to maintain default sizing.

    The GridLayout allows you to specify a horizontal/vertical gap between each component and allows you to control the size of the grid.

    Then you can wrap the panel using a GridLayout in a panel that respects the size of the grid.

    For example you could do:

    JPanel grid = new JPanel( new GridLayout(...) );

JPanel wrapper = new JPanel( new GridBagLayout() );
wrapper.add(grid, new GridBagConstraints());

frame.add(wrapper, BorderLayout.CENTER);

    If you pack the frame, the grid panel will be displayed at is preferred size.

    If you resize the frame the grid panel will remain centered in the wrapper panel.