Changing the JFrame title

Question

This code compiles  I just can t get the name to change on the title bar   import java awt BorderLayout  import java awt event ActionEvent    import java awt event ActionListener    import javax swing JButton    import javax swing JFrame    import javax swing JLabel    import javax swing JPanel    import javax swing JTabbedPane    import javax swing JTextArea    import javax swing JTextField    public class VolumeCalculator extends JFrame implements ActionListener           private JTabbedPane jtabbedPane        private JPanel options        JTextField poolLengthText  poolWidthText  poolDepthText  poolVolumeText  hotTub                hotTubLengthText  hotTubWidthText  hotTubDepthText  hotTubVolumeText  temp  results              myTitle        JTextArea labelTubStatus        public VolumeCalculator                     setSize 400  250             setVisible true             setSize 400  250             setVisible true             setTitle  Volume Calculator              setSize 300  200             JPanel topPanel   new JPanel              topPanel setLayout new BorderLayout               getContentPane   add topPanel              createOptions               jtabbedPane   new JTabbedPane               jtabbedPane addTab  Options   options              topPanel add jtabbedPane  BorderLayout CENTER                   CREATE OPTIONS          public void createOptions                     options   new JPanel              options setLayout null             JLabel labelOptions   new JLabel  Change Company Name               labelOptions setBounds 120  10  150  20             options add labelOptions             JTextField newTitle   new JTextField  Some Title             newTitle setBounds 80  40  225  20             options add newTitle           myTitle   new JTextField               myTitle setBounds 80  40  225  20            myTitle add labelOptions            JButton newName   new JButton  Set New Name              newName setBounds 60  80  150  20             newName addActionListener this             options add newName             JButton Exit   new JButton  Exit              Exit setBounds 250  80  80  20             Exit addActionListener this             options add Exit                 public void actionPerformed ActionEvent event                    JButton button    JButton  event getSource              String buttonLabel   button getText              if   Exit  equalsIgnoreCase buttonLabel                             Exit pressed                  return                        if   Set New Name  equalsIgnoreCase buttonLabel                             New Name                  return                            private void Exit pressed                     System exit 0                 private void New Name                     this setTitle myTitle getText                   private void Options                         public static void main String   args                    JFrame frame   new VolumeCalculator              frame setSize 380  350             frame setVisible true

User · Answer

newTitle is a local variable where you create the fields  So when that functions ends  the variable newTitle  does not exist anymore   The JTextField that was referenced by newTitle does still exist however    Thus  increase the scope of the variable  so that you can access it another method   public SomeFrame extends JFrame      JTextField myTitle   can be used anywhere in this class     creationOfTheFields             other code       myTitle   new JTextField  spam            myTitle setBounds 80  40  225  20         options add myTitle        blabla other code          private void New Name                  this setTitle myTitle getText

User · Answer

I strongly recommend you learn how to use layout managers to get the layout you want to see   null layouts are fragile  and cause no end of trouble   Try this source  amp  check the comments   import java awt BorderLayout  import java awt event ActionEvent  import java awt event ActionListener  import javax swing JButton  import javax swing JFrame  import javax swing JLabel  import javax swing JPanel  import javax swing JTabbedPane  import javax swing JTextArea  import javax swing JTextField   public class VolumeCalculator extends JFrame implements ActionListener       private JTabbedPane jtabbedPane      private JPanel options      JTextField poolLengthText  poolWidthText  poolDepthText  poolVolumeText  hotTub              hotTubLengthText  hotTubWidthText  hotTubDepthText  hotTubVolumeText  temp  results              myTitle      JTextArea labelTubStatus       public VolumeCalculator            setSize 400  250           setVisible true           setSize 400  250           setVisible true           setTitle  Volume Calculator            setSize 300  200           JPanel topPanel   new JPanel            topPanel setLayout new BorderLayout             getContentPane   add topPanel            createOptions             jtabbedPane   new JTabbedPane             jtabbedPane addTab  Options   options            topPanel add jtabbedPane  BorderLayout CENTER                CREATE OPTIONS         public void createOptions            options   new JPanel              options setLayout null           JLabel labelOptions   new JLabel  Change Company Name             labelOptions setBounds 120  10  150  20           options add labelOptions           JTextField newTitle   new JTextField  Some Title              newTitle setBounds 80  40  225  20               options add newTitle           myTitle   new JTextField 20              myTitle WAS NEVER ADDED to the GUI          options add myTitle             myTitle setBounds 80  40  225  20             myTitle add labelOptions           JButton newName   new JButton  Set New Name              newName setBounds 60  80  150  20           newName addActionListener this           options add newName           JButton Exit   new JButton  Exit              Exit setBounds 250  80  80  20           Exit addActionListener this           options add Exit              public void actionPerformed ActionEvent event           JButton button    JButton  event getSource            String buttonLabel   button getText            if   Exit  equalsIgnoreCase buttonLabel                Exit pressed                return                    if   Set New Name  equalsIgnoreCase buttonLabel                New Name                return                       private void Exit pressed            System exit 0              private void New Name            System out println       myTitle getText                   this setTitle myTitle getText                private void Options               public static void main String   args           JFrame frame   new VolumeCalculator            frame pack            frame setSize 380  350           frame setVisible true

User · Answer

these methods can help setTitle  your new title    or  super  your new title

User · Answer

If your class extends JFrame then use this setTitle newTitle getText       If not and it contains a JFrame let s say named myFrame  then use myFrame setTitle newTitle getText      Now that you have posted your program  it is obvious that you need only one JTextField to get the new title  These changes will do the trick    JTextField poolLengthText  poolWidthText  poolDepthText  poolVolumeText  hotTub          hotTubLengthText  hotTubWidthText  hotTubDepthText  hotTubVolumeText  temp  results          newTitle    and          public void createOptions                 options   new JPanel            options setLayout null           JLabel labelOptions   new JLabel  Change Company Name             labelOptions setBounds 120  10  150  20           options add labelOptions           newTitle   new JTextField  Some Title            newTitle setBounds 80  40  225  20           options add newTitle             myTitle   new JTextField  My Title                 myTitle setBounds 80  40  225  20             myTitle add labelOptions           JButton newName   new JButton  Set New Name            newName setBounds 60  80  150  20           newName addActionListener this           options add newName           JButton Exit   new JButton  Exit            Exit setBounds 250  80  80  20           Exit addActionListener this           options add Exit           and   private void New Name         this setTitle newTitle getText

[java] Changing the JFrame title

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