JScrollBar Vertical/Horizontal setting problem- Java Swing

Question

I am just trying to add a vertical scroll bar to my TextField and TextArea. I am using a ScrollPane and it should create avertical/horizontal scroll bar by default.

Problem: I need a vertical scroll bar to see the data which is not visible. In the start a vertical scrollbar appears but when the data increases the vertical scrollbar changes to a horizontal scroll bar. Also the TextField disappears and only a horizontal scrollbar appears in its place. I guess it is because how I have set the bounds but I tried changing the bounds and it ends up completely doing away with the TextField.

My code snippet:

public JTextField inputField = new JTextField();

public  JTextArea talkArea = new JTextArea();

public JScrollPane inputFieldScroll = new JScrollPane(inputField);

public JScrollPane talkAreaScroll = new JScrollPane(talkArea);
      talkArea.setEditable(false);

    talkArea.setBackground(Color.white);

     talkAreaScroll.setBounds(new Rectangle(TALK_LEFT, TALK_TOP, TALK_WIDTH, TALK_HEIGHT));     

     this.getContentPane().add(talkAreaScroll, null);

    //set input area

      inputField.setBackground(Color.white);

    inputField.setBounds(new Rectangle(INPUT_LEFT, INPUT_TOP, INPUT_WIDTH, INPUT_HEIGHT));

    inputFieldScroll.setVerticalScrollBar(new JScrollBar());

    inputFieldScroll.setBounds(new Rectangle(INPUT_LEFT, INPUT_TOP, INPUT_WIDTH, INPUT_HEIGHT));

Question:

Is there some parameter I need to set so that it remains a vertical scroll bar? Why does the input scroll bar occupy the whole inputfield when the data becomes a huge line? It appears as a proper vertical scrollbar in the start.

Any advice appreciated.

Thanks

Answer 1

Below is a small compilable code snippet I mentioned above. I agree with camickr that you should not be using absolute positioning but rather use the layout managers. If you absolutely need to have a horizontal scrollbar for the JTextField, then one way to get it to work is to have it show up always, using the JScrollPane constructor that allows for this. i.e,

        JScrollPane inputPane = new JScrollPane(inputField, JScrollPane.VERTICAL_SCROLLBAR_NEVER, 
                    JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);

For e.g.,

import java.awt.*;
import javax.swing.*;

public class FuSwing1b extends JPanel {
    private static final int TA_ROWS = 25;
    private static final int TA_COLS = 60;
    private JTextField inputField = new JTextField();
    private JTextArea talkArea = new JTextArea(TA_ROWS, TA_COLS);

    public FuSwing1b() {
        talkArea.setEditable(false);
        talkArea.setFocusable(false);
        talkArea.setBackground(Color.white);
        //talkArea.setPreferredSize(new Dimension(TALK_WIDTH, TALK_HEIGHT));

        JScrollPane talkPane = new JScrollPane(talkArea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, 
                    JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
        JScrollPane inputPane = new JScrollPane(inputField, JScrollPane.VERTICAL_SCROLLBAR_NEVER, 
                    JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);

        int gap = 10;
        setLayout(new BorderLayout(gap, gap));
        add(talkPane, BorderLayout.CENTER);
        add(inputPane, BorderLayout.SOUTH);
        setBorder(BorderFactory.createEmptyBorder(gap , gap, gap, gap));
    }

    private static void createAndShowUI() {
        JFrame frame = new JFrame("FuSwing1b");
        frame.getContentPane().add(new FuSwing1b());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                createAndShowUI();
            }
        });
    }
}

Answer 2

Don't play with the bounds. Use a layout manager and you won't have to worry about this.

When you create the text field use something like:

JTextField textField = new JTextField(10);

This will create a text field that will hold a minimum of 10 characters. If the number of characters exceeds the display width of the text field the use can see the remaining characters by using the right/left arrow keys. That is the normal UI used by all applications I have ever seen. Don't try to create your own UI by using a horizontal scrollbar. Users are not accustomed to that.

for the text area you can create it using:

JTextArea textArea = new JTextArea(5, 30);
JScrollPane scrollPane = new JScrollPane( textArea );

to create a text area with 5 rows and approximately 30 character per row.

Now add the text field and the scrollpane to your frame "using layout managers" and then pack the frame. The layout managers will determine the best size for the compoents. Scrollbars will automatically appear on the text area as you add text to it and the text exceeds 5 lines.