如何使用Container添加填充？

Question

I am trying to make on top some padding but how to do this with Container?

    JFrame frame = super.screen.getFullScreenWindow();
    //Container contentPane = frame.getContentPane();
    //JPanel contentPane = new JPanel();

    // Make sure the content pane is transparent
    if (contentPane instanceof JComponent) {
        ((JComponent)contentPane).setOpaque(false);
    } 
    else {
      // ??
    }

    contentPane.setBorder(new EmptyBorder(10, 10, 10, 10) );
    //frame.getContentPane().add(contentPane, BorderLayout.CENTER);

Output

 [javac] symbol  : method setBorder(javax.swing.border.EmptyBorder)
 [javac] location: class java.awt.Container 
 [javac] contentPane.setBorder(new EmptyBorder(10, 10, 10, 10) );
 [javac]

Answer 1

Can't you simply add a JPanel to contain everything and set empty border on that ?

 JPanel containerPanel = new JPanel();
 containerPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
 containerPanel.setLayout(new BorderLayout());
 //panel to test
 JPanel testPanel = new JPanel();
 testPanel.setBackground(Color.blue);        
 containerPanel.add(testPanel,BorderLayout.CENTER);

 //assuming you are extending JFrame
 getContentPane().setLayout(new BorderLayout());
 getContentPane().add(containerPanel, BorderLayout.CENTER);

Answer 2

• JFrame / Frame and its ContentPane doesn't implements Borders , this is prehistoric Componenet

• put directly there JPanel with EmptyBorders

• for Java5 and higher isn't required to call for ContentPane (only for setBackground:-) , you can directly add JComponents to the JFrame#add(myJComponent) , notice Swing Top-Level Containers have got implemented BorderLayout by default

Answer 3

您可以覆盖Container＃getInsets ，但您应该使用Swing组件。

Answer 4

don't you prefer to use swing ? Components have a method to add margins. Swing is far better than the obsolete awt library.