每当我更改同一 JPanel 中其他 JLabels 的文本时，如何停止 JLabels 在 JPanel 内更改的位置？

Question

I have multiple JLabels in a JPanel. Whenever I change the text in one, it causes the other JLabels inside the JPanel to move. How to I lock them in place?

Answer 1

The approach really depends how you labels are positioned and what LayoutManager you are using.

JLabel by default will calculate its size mostly based on the label text and font size. If you are changing the text, then the JLabel size will change as well and thus make the layout manager to reposition the other labels.

Here is an example that uses FlowLayout and hard sets JLabel preferred size so that it wont change when its text changes. Other layout managers might choose to ignore the preferred size:

    JFrame frame = new JFrame();
    frame.getContentPane().setLayout( new FlowLayout() );

    JLabel l = new JLabel("text1");
    l.setPreferredSize( new Dimension( 50, (int)l.getPreferredSize().getHeight() ) );
    frame.getContentPane().add(l);

    frame.getContentPane().add( new JLabel("text2") );
    frame.getContentPane().add( new JLabel("text3") );

Here if you change text for l it wont shift the other 2 labels.