How to set border on jPanel

Question

My projects constists of two classes  GoBoard extends JPanel   GoTest java   import javax swing    import java awt Graphics  import java io    import java awt     import javax swing border Border  import javax swing border LineBorder   class GoTest      private static void initGui            JFrame frame   new JFrame  GoBoard            GoBoard jboard   new GoBoard            jboard setLayout new BorderLayout 10 10            jboard setBorder BorderFactory createEmptyBorder 0 10 10 10             frame add jboard              frame setDefaultCloseOperation JFrame EXIT ON CLOSE           frame setSize 400  400           frame pack            frame setVisible true              public static void main String   args           javax swing SwingUtilities invokeLater new Runnable                public void run                    initGui                                        GoBoard java   import javax swing    import java awt Graphics  import javax swing border Border  class GoBoard extends JPanel      private int linien       public GoBoard            this 9                  public GoBoard int pLinien           this linien   pLinien          this setBorder BorderFactory createEmptyBorder 0 10 10 10                public void paintComponent Graphics g           super paintComponent g           int d   0          int h   0          for int i   0  i  lt  this linien  i                 g drawLine 0 h  getWidth    h               g drawLine d 0 d getHeight                 h    getHeight   this linien              d   getWidth   this linien                      I want to set a border to have padding according to the frame where I display the panel  However I get no border  Any idea

User · Answer

To get fixed padding  I will set layout to java awt GridBagLayout with one cell   You can then set padding for each cell  Then you can insert inner JPanel to that cell and  if you need  delegate proper JPanel methods to the inner JPanel

User · Answer

JPanel jPanel   new JPanel     jPanel setBorder BorderFactory createLineBorder Color black      Here not only jPanel  you can add border to any Jcomponent

User · Answer

An empty border is transparent   You need to specify a Line Border or some other visible border when you set the border in order to see it   Based on Edit to question   The painting does not honor the border   Add this line of code to your test and you will see the border       jboard setBorder BorderFactory createEmptyBorder 0 10 10 10         jboard add new JButton  Test        Add this line     frame add jboard

User · Answer

BorderLayout int Gap  int Gap  or GridLayout int Gap  int Gap  int Gap  int Gap   why paint Border   inside paintComponent            Border line  raisedbevel  loweredbevel  title  empty      line   BorderFactory createLineBorder Color black       raisedbevel   BorderFactory createRaisedBevelBorder        loweredbevel   BorderFactory createLoweredBevelBorder        title   BorderFactory createTitledBorder          empty   BorderFactory createEmptyBorder 4  4  4  4       Border compound   BorderFactory createCompoundBorder empty  xxx       Color crl    Color blue       Border compound1   BorderFactory createCompoundBorder empty  xxx

User · Answer

Possibly the problem is your two constructor overloads  one that sets the border  the other that doesn t   public GoBoard        this linien   9      this setBorder BorderFactory createEmptyBorder 0 10 10 10        public GoBoard int pLinien       this linien   pLinien       If you create a GoBoard object with the second constructor and pass an int parameter  the empty border will not be created   To fix this  consider changing this so both constructors set the border      default constructor public GoBoard        this 9       calls other constructor    public GoBoard int pLinien       this linien   pLinien      this setBorder BorderFactory createEmptyBorder 0 10 10 10         edit 1  The border you ve added is more for controlling how components are added to your JPanel   If you want to draw in your one JPanel but have a border around the drawing  consider placing this JPanel into another JPanel  a holding JPanel that has the border   For e g    class GoTest      private static final int JB WIDTH   400     private static final int JB HEIGHT   JB WIDTH      private static void initGui           JFrame frame   new JFrame  GoBoard          GoBoard jboard   new GoBoard          jboard setLayout new BorderLayout 10  10           JPanel holdingPanel   new JPanel new BorderLayout           int eb   20        holdingPanel setBorder BorderFactory createEmptyBorder 0  eb  eb  eb          holdingPanel add jboard  BorderLayout CENTER         frame add holdingPanel  BorderLayout CENTER         jboard setPreferredSize new Dimension JB WIDTH  JB HEIGHT           frame setDefaultCloseOperation JFrame EXIT ON CLOSE              frame setSize 400  400         frame pack          frame setVisible true                 etc

User · Answer

Swing has no idea what the preferred  minimum and maximum sizes of the GoBoard should be as you have no components inside of it for it to calculate based on  so it picks a  probably wrong  default  Since you are doing custom drawing here  you should implement these methods  Dimension getPreferredSize   Dimension getMinumumSize   Dimension getMaximumSize     or conversely  call the setters for these methods

[java] How to set border on jPanel?

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