Scroll Bars

[Rose Evans]

Ok you guys...it's me again.
I'm trying to make these scroll bar things, and so far I have them working, but I need to do some type of coding somewhere so that the user can pick to where he or she wants scroll bars, always, never, or as needed.
When the user makes a choice the scroll bars are displayed according to their choice.
I created a 'Scroll Bar Menu', but I know it needs some type of coding somewhere to give the user a choice....

Please do you have any suggestions...and remember tell me in 'small talk'.

Here's my code...

  
 
public class MemoGUI extends JFrame implements ActionListener
{
    public static final int WIDTH = 600;
    public static final int HEIGHT = 300;
    public static final int LINES = 10;
    public static final int CHAR_PER_LINE = 40;
 

 
    private JTextArea theText;
    private String memo1 = "No Memo 1.";
    private String memo2 = "No Memo 2.";
 
    public MemoGUI( )
    {
        setSize(WIDTH, HEIGHT);
        addWindowListener(new WindowDestroyer( ));
        setTitle("Memo Saver");
        Container contentPane = getContentPane( );
        contentPane.setLayout(new BorderLayout( ));
 

        JMenu memoMenu = new JMenu("Memos");
        JMenuItem m;
 
        m = new JMenuItem("Scroll Bars");
        m.addActionListener(this);
        memoMenu.add(m);
 
        m = new JMenuItem("Save Memo 1");
        m.addActionListener(this);
        memoMenu.add(m);
 
        m = new JMenuItem("Save Memo 2");
        m.addActionListener(this);
        memoMenu.add(m);
 
        m = new JMenuItem("Get Memo 1");
        m.addActionListener(this);
        memoMenu.add(m);
 
        m = new JMenuItem("Get Memo 2");
        m.addActionListener(this);
        memoMenu.add(m);
 
        m = new JMenuItem("Clear");
        m.addActionListener(this);
        memoMenu.add(m);
 

        m = new JMenuItem("Exit");
        m.addActionListener(this);
        memoMenu.add(m);
 
        JMenuBar mBar = new JMenuBar( );
        mBar.add(memoMenu);
        setJMenuBar(mBar);
 

        JPanel textPanel = new JPanel( );
textPanel.setBackground(Color.BLUE);
theText = new JTextArea(LINES, CHAR_PER_LINE);
theText.setBackground(Color.WHITE);
JScrollPane scrolledText = new JScrollPane(theText);
 
scrolledText.setHorizontalScrollBarPolicy(
    JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
scrolledText.setVerticalScrollBarPolicy(
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);//check here...
 

 
textPanel.add(scrolledText);
        contentPane.add(textPanel, BorderLayout.CENTER);
 

    }
 
    public void actionPerformed(ActionEvent e)
    {
        String actionCommand = e.getActionCommand( );
        if (actionCommand.equals("Save Memo 1"))
            memo1 = theText.getText( );
        else if (actionCommand.equals("Save Memo 2"))
            memo2 = theText.getText( );
        else if (actionCommand.equals("Clear"))
            theText.setText("");
        else if (actionCommand.equals("Get Memo 1"))
            theText.setText(memo1);
        else if (actionCommand.equals("Get Memo 2"))
            theText.setText(memo2);
      //  else if (actionCommand.equals("Scroll Bar"))
 
        else if (actionCommand.equals("Exit"))
            System.exit(0);
        else
            theText.setText("Error in memo interface");
    }
 
    public static void main(String[] args)
    {
 

 
        MemoGUI gui = new MemoGUI( );
        gui.setVisible(true);
 

    }
}

[Jeff Tian]

Hi there Rose.

I think this is kinda what U R looking for. The submenu lets user choose b/n the always and never modes.

I had a submenu, with radio buttons and action listeners for them.

Put some of the variables as instance instead of local so action listener can reuse them.

Then I just set them according to listeners.

And I dunno what windowDestroyer is. Must be some weapon against bill gates.

It's messy. But here it is.

 import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
 
public class MemoGUI extends JFrame implements ActionListener
{    
public static final int WIDTH = 600;    
public static final int HEIGHT = 300;    
public static final int LINES = 10;    
public static final int CHAR_PER_LINE = 40;      
private JTextArea theText;    
private String memo1 = "No Memo 1.";    
private String memo2 = "No Memo 2.";

private JMenu memoMenu = new JMenu("Memos");
private JMenu subMenu;         
private JMenuItem m;   
private JRadioButtonMenuItem rbMenuItem;   
private JPanel textPanel;
private Container contentPane;
private JScrollPane scrolledText;

public MemoGUI( )    
{        
setSize(WIDTH, HEIGHT);        
//addWindowListener(new WindowDestroyer( ));        
setTitle("Memo Saver");        
contentPane = getContentPane( );        
contentPane.setLayout(new BorderLayout( ));         


        
subMenu = new JMenu("Scroll Bars");

memoMenu.addSeparator();
ButtonGroup group = new ButtonGroup();
rbMenuItem = new JRadioButtonMenuItem("ScrollAlways");
rbMenuItem.setSelected(true);
rbMenuItem.setMnemonic(KeyEvent.VK_R);
group.add(rbMenuItem);
rbMenuItem.addActionListener(this);   
subMenu.add(rbMenuItem);
 
rbMenuItem = new JRadioButtonMenuItem("ScrollNever");
rbMenuItem.setMnemonic(KeyEvent.VK_O);
group.add(rbMenuItem);
rbMenuItem.addActionListener(this);   
subMenu.add(rbMenuItem);
 
 



memoMenu.add(subMenu);         
m = new JMenuItem("Save Memo 1");        
m.addActionListener(this);        
memoMenu.add(m);         
m = new JMenuItem("Save Memo 2");        
m.addActionListener(this);        
memoMenu.add(m);         
m = new JMenuItem("Get Memo 1");        
m.addActionListener(this);        
memoMenu.add(m);         
m = new JMenuItem("Get Memo 2");        
m.addActionListener(this);        
memoMenu.add(m);         
m = new JMenuItem("Clear");        
m.addActionListener(this);        
memoMenu.add(m);         
m = new JMenuItem("Exit");        
m.addActionListener(this);        
memoMenu.add(m);         
JMenuBar mBar = new JMenuBar( );        
mBar.add(memoMenu);        
setJMenuBar(mBar);         
textPanel = new JPanel( );
textPanel.setBackground(Color.BLUE);
theText = new JTextArea(LINES, CHAR_PER_LINE);
theText.setBackground(Color.WHITE);


scrolledText = new JScrollPane(theText); 
//scrolledText.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
//scrolledText.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
//check here...  
textPanel.add(scrolledText);        
contentPane.add(textPanel, BorderLayout.CENTER);     
}     

public void actionPerformed(ActionEvent e)    
{        
String actionCommand = e.getActionCommand( );        
if (actionCommand.equals("Save Memo 1"))            
memo1 = theText.getText( );
else if (actionCommand.equals("ScrollAlways"))
{
 
scrolledText.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
scrolledText.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
textPanel.add(scrolledText);        
contentPane.add(textPanel, BorderLayout.CENTER);

 

}
else if (actionCommand.equals("ScrollNever"))
{
scrolledText.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scrolledText.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_NEVER);
textPanel.add(scrolledText);        
contentPane.add(textPanel, BorderLayout.CENTER);

 
}

else if (actionCommand.equals("Save Memo 2"))            
memo2 = theText.getText( );        
else if (actionCommand.equals("Clear"))            
theText.setText("");        
else if (actionCommand.equals("Get Memo 1"))            
theText.setText(memo1);        
else if (actionCommand.equals("Get Memo 2"))            
theText.setText(memo2);      //  else if (actionCommand.equals("Scroll Bar"))         
else if (actionCommand.equals("Exit"))            
System.exit(0);        
else            
theText.setText("Error in memo interface");    
}     


 

public static void main(String[] args)    
{          
MemoGUI gui = new MemoGUI( );        
gui.setVisible(true);     
}
}


 

[ April 12, 2005: Message edited by: Jeff Tian ]

[Craig Wood]

There are a number of ways you could go about this. One might be to launch
a JOptionPane to get the users choice in scrollbar policy. Another might be
to add a submenu to the "Scroll Bars" menu item and list the three choices
for scrollbar policy, perhaps as JRadioButtonMenuItems. In actionPerformed
you could call a method that makes the desired/selected changes, perhaps
sending along a member variable flag to indicate the selection. And to
facilitate the changes you could move the declaration for the JScrollPane
into class scope, ie, make scrolledText a member variable instead of
a local variable. In java this might look like:

public class MemoGUI extends JFrame implements ActionListener
{
    ...
    JScrollPane scrolledText;  // declaration is now a member variable
    final int                  // some communication helpers - flags
        ALWAYS    = 0,
        NEVER     = 1,
        AS_NEEDED = 2;
 
    public MemoGUI( )
    {
        ...
        JMenu scrollMenu = new JMenu("scroll bars");
        m = new JMenuItem("always");
        m.addActionListener(this);
        scrollMenu.add(m);
        m = new JMenuItem("never");
        m.addActionListener(this);
        scrollMenu.add(m);
        m = new JMenuItem("as needed");
        m.addActionListener(this);
        scrollMenu.add(m);
        memoMenu.add(scrollMenu);
        ...
        // [I]scrolledText[/I] is no longer a local variable - it's
        // declaration has been moved into class scope as a
        // member variable so everyone in the class can see it
        scrolledText = new JScrollPane(theText);
        textPanel.add(scrolledText);
        ...
 
    public void actionPerformed(ActionEvent e)
    {
        ...
        else if (actionCommand.equals("always"))
            resetScrollBarPolicy(ALWAYS);
        else if (actionCommand.equals("never"))
            resetScrollBarPolicy(NEVER);
        else if (actionCommand.equals("as needed"))
            resetScrollBarPolicy(AS_NEEDED);
        ...
 
    private void resetScrollBarPolicy(int policy)
    {
        switch(policy)
        {
            case ALWAYS:
                scrolledText.setHorizontalScrollBarPolicy(
                                 JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
                scrolledText.setVerticalScrollBarPolicy(
                                 JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
                break;
            case NEVER:
                scrolledText.setHorizontalScrollBarPolicy(
                                 JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
                scrolledText.setVerticalScrollBarPolicy(
                                 JScrollPane.VERTICAL_SCROLLBAR_NEVER);
                break;
            default:    // AS_NEEDED
                scrolledText.setHorizontalScrollBarPolicy(
                                 JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
                scrolledText.setVerticalScrollBarPolicy(
                                 JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);
        }
    }

[ April 12, 2005: Message edited by: Craig Wood ]

[Rose Evans]

Well I tried something else....and I get these errors...

F:\Java II\14.2\MemoGUI.java:115: int cannot be dereferenced
scrolledText.setHorizontalScrollBarPolicy(
^
F:\Java II\14.2\MemoGUI.java:117: int cannot be dereferenced
scrolledText.setVerticalScrollBarPolicy(
^
2 errors

Tool completed with exit code 1

 
 
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
 
public class MemoGUI extends JFrame implements ActionListener
{
    public static final int WIDTH = 600;
    public static final int HEIGHT = 300;
    public static final int LINES = 10;
    public static final int CHAR_PER_LINE = 40;
 

 
    private JTextArea theText;
    private String memo1 = "No Memo 1.";
    private String memo2 = "No Memo 2.";
    int  scrolledText;
 

    public MemoGUI( )
    {
        setSize(WIDTH, HEIGHT);
        addWindowListener(new WindowDestroyer( ));
        setTitle("Memo Saver");
        Container contentPane = getContentPane( );
        contentPane.setLayout(new BorderLayout( ));
 

        JMenu memoMenu = new JMenu("Memos");
        JMenuItem m;
 

        m = new JMenuItem("Save Memo 1");
        m.addActionListener(this);
        memoMenu.add(m);
 
        m = new JMenuItem("Save Memo 2");
        m.addActionListener(this);
        memoMenu.add(m);
 
        m = new JMenuItem("Get Memo 1");
        m.addActionListener(this);
        memoMenu.add(m);
 
        m = new JMenuItem("Get Memo 2");
        m.addActionListener(this);
        memoMenu.add(m);
 
        m = new JMenuItem("Clear");
        m.addActionListener(this);
        memoMenu.add(m);
 

        m = new JMenuItem("Exit");
        m.addActionListener(this);
        memoMenu.add(m);
 
        JMenuBar mBar = new JMenuBar( );
        mBar.add(memoMenu);
        setJMenuBar(mBar);
 

 

 

        JPanel textPanel = new JPanel( );
textPanel.setBackground(Color.BLUE);
theText = new JTextArea(LINES, CHAR_PER_LINE);
theText.setBackground(Color.WHITE);
JScrollPane scrolledText = new JScrollPane(theText);
 

JMenu scrollMenu = new JMenu("Scroll Bars");
        JMenuItem s;
 
        s = new JMenuItem("Never");
        s.addActionListener(this);
        scrollMenu.add(s);
 
        s = new JMenuItem("Always");
        s.addActionListener(this);
        scrollMenu.add(s);
 
        s = new JMenuItem("As Needed");
        scrollMenu.add(s);
 
        mBar.add (scrollMenu);
 

textPanel.add(scrolledText);
        contentPane.add(textPanel, BorderLayout.CENTER);
 

    }
 
    public void actionPerformed(ActionEvent e)
    {
        String actionCommand = e.getActionCommand( );
        if (actionCommand.equals("Save Memo 1"))
            memo1 = theText.getText( );
        else if (actionCommand.equals("Save Memo 2"))
            memo2 = theText.getText( );
        else if (actionCommand.equals("Clear"))
            theText.setText("");
        else if (actionCommand.equals("Get Memo 1"))
            theText.setText(memo1);
        else if (actionCommand.equals("Get Memo 2"))
            theText.setText(memo2);
        else if (actionCommand.equals("Always"))
 
        {
 

scrolledText.setHorizontalScrollBarPolicy(
JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
scrolledText.setVerticalScrollBarPolicy(
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
    }
 

        else if (actionCommand.equals("Exit"))
            System.exit(0);
        else
            theText.setText("Error in memo interface");
    }
 
    public static void main(String[] args)
    {
 

 
        MemoGUI gui = new MemoGUI( );
        gui.setVisible(true);
 

    }
}
 
This is my new code...don't know what the heck I'm doing wrong...shoot. 
 

 

[Rose Evans]

Jeff...by the way...windows destroyer ...destroys the window when the user is finished with it....I guess you can say it like that.