CODEWITHSUNDEEP
javaswing
james_dean
james_dean

Reputation: 1517

JScrollPane won't display

I'd like to create a simple GUI based 'Echo' application with the ability to scroll up and down through previous input. So far, everything is working except when I add the JTextPane to the JScrollPane, I lose the input and the scroll never appears.

Can someone point me in the right direction?

Scroll pane

Here is the code I have so far:

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

public class FileReaderGui {
    private JFrame frame;
    private JPanel inputPanel;
    private JTextField userInput;

    private JScrollPane scrollPane;
    private JTextPane display;
    JButton print;

    public void show() {
        frame = new JFrame();
        frame.setSize(400, 200);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        buildInputPanel();
        buildDisplayPanel();
        frame.getContentPane().add(inputPanel, BorderLayout.SOUTH);
        frame.getContentPane().add(scrollPane, BorderLayout.CENTER);

        frame.setVisible(true);
    }

    public void buildDisplayPanel() {
        display = new JTextPane();
            scrollPane = new JScrollPane(display);
    }

    public void buildInputPanel() {
        inputPanel = new JPanel();

        userInput = new JTextField();
        userInput.setColumns(20);
        inputPanel.add(userInput);

        print = new JButton("Print");
        print.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                String current = display.getText();
                String input = userInput.getText();

                String newText = String.format("%s\n%s", current, input);
                display.setText(newText);
            }
        });
        inputPanel.add(print);
    }
}

And, here is the caller:

public class FileReader {
    public void go() {
        FileReaderGui gui = new FileReaderGui();
        gui.show();
    }

    public static void main(String[] args) {
        new FileReader().go();
    }
}

Upvotes: 0

Views: 840

Answers (2)

user3507600
user3507600

Reputation: 1075

Just got a chance to test the code, my suggestion in the comments works for me.

Either way here are two options:

public void buildDisplayPanel() {
    display = new JTextPane();
    scrollPane = new JScrollPane();
    scrollPane.getViewport().add(display);
}

or as I suggested above:

public void buildDisplayPanel() {
    display = new JTextPane();
    scrollPane = new JScrollPane(display);
}

They both seem to work for me in my tests locally.

As eluded to in the JavaDoc I linked in the comment above, the JScrollPane displays the associated JViewport, which can be retrieved and added to (first example) or created upon initialization (second example); you could also use the setViewport() function described for JScrollPane

Upvotes: 1

camickr
camickr

Reputation: 324078

 I'd say you should have scrollPane = new JScrollPane(display);

I also agree with the above.

Did you reorder your code to make sure you created the text pane before creating the scrollpane?

    //scrollPane = new JScrollPane();
    //display = new JTextPane();
    //scrollPane.add(display);

    display = new JTextPane();
    scrollPane = new JScrollPane(display);

If that doesn't help then post your SSCCE that includes you main() method to execute your code.

Upvotes: 1

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