Please help me understanding BoxLayout alignment issues

Question

I'm trying to create a very simple window using Java Layouts. I have got three elements to arrange: a button, a progress bar and a label. The button has to be vertically centered, the progress bar has to take full width, and the label has to be left aligned.

Here's some code (just assume pane is the content pane of a JFrame, and button, progressBar and label have been created before):

BoxLayout layout = new BoxLayout(pane, BoxLayout.Y_AXIS);
pane.setLayout(layout);
button.setAlignmentX(Component.CENTER_ALIGNMENT);
pane.add(button);
progressBar.setAlignmentX(Component.CENTER_ALIGNMENT);
pane.add(progressBar);
label.setAlignmentX(Component.LEFT_ALIGNMENT);
pane.add(label);

When I test the application I see everything misaligned and screwed up: the button and the label are randomly indented, and if I resize the window the indentation amount changes in a strange way. The progress bar looks good (full width).

I just don't understand what's happening. Can you give me a clue?

Answer 1

BoxLayout cannot handle different alignments: see http://download.oracle.com/javase/tutorial/uiswing/layout/box.html

quoting from that article: "In general, all the components controlled by a top-to-bottom BoxLayout object should have the same X alignment. Similarly, all the components controlled by a left-to-right Boxlayout should generally have the same Y alignment."