JTextArea Auto-Resize

It is inside a JScrollPane, however when there are too many lines of text the text just goes off the bottom out of view and you can't scroll to see it.

jjdevinea at 2007-7-29 16:07:50 >

package toDo.gui;

import java.awt.Color;

import java.awt.Container;

import java.awt.Dimension;

import java.awt.FlowLayout;

import java.awt.Font;

import java.awt.Toolkit;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.*;

import javax.swing.border.LineBorder;

import toDo.data.ToDoHolder;

public class LogToDo extends JFrame implements ActionListener

{

private static final long serialVersionUID = -5545406794821718167L;

private int sWidth = 500,sHeight = 620;

private ToDoHolder holder;

private JPanel panelHeader, panelHistory, panelAppend;

private JLabel lHeader, lHistory;

private JTextArea taHistory, taAppend;

private JButton bAppend, bClose;

private MainGui main;

public LogToDo(ToDoHolder holder, MainGui m)

{

super("To Do Log");//form heading

//create container to place components in:

Container container = getContentPane();

container.setLayout(new FlowLayout());//set flow layout

//store references

this.holder = holder;

main = m;

panelHeader = new JPanel();

panelHistory = new JPanel();

panelAppend = new JPanel();

panelHeader.setPreferredSize(new Dimension(470,50));

panelHistory.setPreferredSize(new Dimension(470,300));

panelAppend.setPreferredSize(new Dimension(470,205));

panelHeader.setBorder(new LineBorder(Color.BLACK));

panelHistory.setBorder(new LineBorder(Color.BLACK));

panelAppend.setBorder(new LineBorder(Color.BLACK));

/*

* header panel

*/

String desc = holder.getDescription();

if (desc.length() > 20)

{

desc = desc.substring(0,18) + "...";

}

lHeader = new JLabel("Log for : " + desc);

lHeader.setFont(new Font("Comic Sans MS" , Font.BOLD, 24));

panelHeader.add(lHeader);

/*

* history panel

*/

lHistory = new JLabel("Log History :");

taHistory = new JTextArea();

taHistory.setPreferredSize(new Dimension(410,5000));

taHistory.setLineWrap(true);

taHistory.setWrapStyleWord(true);

taHistory.setEditable(false);

taHistory.setText(holder.getLog());

JScrollPane jsp = new JScrollPane(taHistory);

jsp.setPreferredSize(new Dimension(450,260));

jsp.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);

panelHistory.add(lHistory);

panelHistory.add(jsp, FlowLayout.CENTER);

/*

* append panel

*/

taAppend = new JTextArea();

taAppend.setPreferredSize(new Dimension(410,1000));

taAppend.setLineWrap(true);

taAppend.setWrapStyleWord(true);

bAppend = new JButton("Append");

bClose = new JButton("Close");

Dimension dButton = new Dimension(220,25);

bAppend.setPreferredSize(dButton);

bClose.setPreferredSize(dButton);

bAppend.addActionListener(this);

bClose.addActionListener(this);

jsp = new JScrollPane(taAppend);

jsp.setPreferredSize(new Dimension(450,160));

jsp.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);

panelAppend.add(jsp);

panelAppend.add(bAppend);

panelAppend.add(bClose);

/*

* add panels to container

*/

container.add(panelHeader);

container.add(panelHistory);

container.add(panelAppend);

Dimension d = Toolkit.getDefaultToolkit().getScreenSize();//get screen resoloution

setLocation((d.width-sWidth)/2, (d.height-sHeight)/2);//centre form

setSize(sWidth,sHeight);//set form size

setVisible(true);//display screen

}

public void actionPerformed(ActionEvent e)

{

if (e.getSource() == bAppend)

{

String appText = taAppend.getText().trim();

if(appText.length() < 1)

{

JOptionPane.showMessageDialog(null, "You can't append an empty message!", "Error", JOptionPane.ERROR_MESSAGE);

}

else //append comments

{

holder.addToLog(ToDoHolder.LOG_COMMENT, appText);

taHistory.setText(holder.getLog());

taAppend.setText("");

taAppend.requestFocus();

main.refreshToDoDisplay();

System.out.println("boo");

}

}

if (e.getSource() == bClose)

{

dispose();

}

}

}

It is taHistory I mean, when "taHistory.setText(holder.getLog());" returns so many lines of text that they dont fit in the JTextArea, the text goes off the bottom of the JTextArea where you cant see it. I would like the vertical length of the JTextArea inside the JScrollPane to increase as needed so that all text can be viewed. I tried what you said but it doesn't change anything.

Thanks.

jjdevinea at 2007-7-29 16:07:50 >

Sorry I am not familiar with how to use these forums i will bear that in mind in future.

I don't think you understand the problem (sorry if my explanation is poor), I will try to explain it step by step.

I have created a large JTextArea:

taHistory.setPreferredSize(new Dimension(410,5000));

I have placed it inside a smaller JScrollPane:

JScrollPane jsp = new JScrollPane(taHistory);

jsp.setPreferredSize(new Dimension(450,260));

jsp.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);

The user fills in a JTextArea called taAppend, then they click a button (called bAppend). The text appends on the end of the text in taHistory.

Although taHistory has a height of 5000, it will eventually not be large enough to show all the text (because more and more gets appended to it).

What I need is for the height of taHistory to increase when text is appended so that all the text is visible (and not off the bottom of the component).

i've created a runnable version of this class (nothing necessary cut out):

import java.awt.Color;

import java.awt.Container;

import java.awt.Dimension;

import java.awt.FlowLayout;

import java.awt.Font;

import java.awt.Toolkit;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.*;

import javax.swing.border.LineBorder;

public class LogToDo extends JFrame implements ActionListener

{

private static final long serialVersionUID = -5545406794821718167;

private int sWidth = 500,sHeight = 620;

//private ToDoHolder holder;

private JPanel panelHeader, panelHistory, panelAppend;

private JLabel lHeader, lHistory;

private JTextArea taHistory, taAppend;

private JButton bAppend, bClose;

//private MainGui main;

public static void main(String[] args)

{

new LogToDo();

}

public LogToDo()

{

super("To Do Log");//form heading

//create container to place components in:

Container container = getContentPane();

container.setLayout(new FlowLayout());//set flow layout

//store references

//this.holder = holder;

//main = m;

panelHeader = new JPanel();

panelHistory = new JPanel();

panelAppend = new JPanel();

panelHeader.setPreferredSize(new Dimension(470,50));

panelHistory.setPreferredSize(new Dimension(470,300));

panelAppend.setPreferredSize(new Dimension(470,205));

panelHeader.setBorder(new LineBorder(Color.BLACK));

panelHistory.setBorder(new LineBorder(Color.BLACK));

panelAppend.setBorder(new LineBorder(Color.BLACK));

/*

* header panel

*/

//String desc = holder.getDescription();

/*if (desc.length() > 20)

{

desc = desc.substring(0,18) + "...";

}*/

lHeader = new JLabel("Log for : ");

lHeader.setFont(new Font("Comic Sans MS" , Font.BOLD, 24));

panelHeader.add(lHeader);

/*

* history panel

*/

lHistory = new JLabel("Log History :");

taHistory = new JTextArea();

taHistory.setPreferredSize(new Dimension(410,1000));

taHistory.setLineWrap(true);

taHistory.setWrapStyleWord(true);

taHistory.setEditable(false);

taHistory.setText("");

JScrollPane jsp = new JScrollPane(taHistory);

jsp.setPreferredSize(new Dimension(450,260));

jsp.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);

panelHistory.add(lHistory);

panelHistory.add(jsp, FlowLayout.CENTER);

/*

* append panel

*/

taAppend = new JTextArea();

taAppend.setPreferredSize(new Dimension(410,1000));

taAppend.setLineWrap(true);

taAppend.setWrapStyleWord(true);

bAppend = new JButton("Append");

bClose = new JButton("Close");

Dimension dButton = new Dimension(220,25);

bAppend.setPreferredSize(dButton);

bClose.setPreferredSize(dButton);

bAppend.addActionListener(this);

bClose.addActionListener(this);

jsp = new JScrollPane(taAppend);

jsp.setPreferredSize(new Dimension(450,160));

jsp.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);

panelAppend.add(jsp);

panelAppend.add(bAppend);

panelAppend.add(bClose);

/*

* add panels to container

*/

container.add(panelHeader);

container.add(panelHistory);

container.add(panelAppend);

Dimension d = Toolkit.getDefaultToolkit().getScreenSize();//get screen resoloution

setLocation((d.width-sWidth)/2, (d.height-sHeight)/2);//centre form

setSize(sWidth,sHeight);//set form size

setVisible(true);//display screen

}

public void actionPerformed(ActionEvent e)

{

if (e.getSource() == bAppend)

{

String appText = taAppend.getText().trim();

if(appText.length() < 1)

{

JOptionPane.showMessageDialog(null, "You can't append an empty message!", "Error", JOptionPane.ERROR_MESSAGE);

}

else //append comments

{

//holder.addToLog(ToDoHolder.LOG_COMMENT, appText);

taHistory.setText(taHistory.getText() + "\n" + taAppend.getText());

taAppend.setText("");

int length = taHistory.getDocument().getLength();

taHistory.setCaretPosition(length);

taAppend.requestFocus();

//main.refreshToDoDisplay();

System.out.println("boo");

}

}

if (e.getSource() == bClose)

{

dispose();

}

}

}

If you keep appending text you will see it eventually goes off the bottom...

jjdevinea at 2007-7-29 16:07:50 >

Container contentPane=getContentPane();

JPanel panel=new JPanel();

JTextArea ta=new JTextArea(10,50);

JScrollPane scrollPane=new JScrollPane(ta);

JTextField tf=new JTextField(40);

contentPane.add(scrollPane,BorderLayout.NORTH);

panel.add(tf);

contentPane.add(panel,BorderLayout.SOUTH);

scrollPane.getVerticalScrollBar().setValue(scrollPane.getVerticalScrollBar().getMaximum());

}//this fuction makes the scrollbar movedown with every extra line

this is just a piece of code to show you as a example how it can be made

noobs_will_rulea at 2007-7-29 16:07:50 >