I already read/tried these posts but that didn't help:
Display multiple lines within a Jlist cell
How to get multiline for a Jlist text?
Problem displaying components of JList
What I need is a ListCellRenderer which returns a panel with an icon on the left and a text of dynamic length on the right (like in any forum: on the left a user avatar, on the right the post text). The texts are NOT known to me, so I can't set a fixed cell height. Further, the text length differs from list cell to list cell. So every list cell needs its own height depending on the length of the text. Actually a really common layout ... but not for Swing. The cell height just doesn't expand according to the text length.
I already read almost any post out there about dynamic cell heights and multiline texts in JList, but couldn't find a solution. So I decided to give a small SSCCE. Please give me a hint on how to achieve what I described or please fix my code if you think it's easy.
Thanks
Here is ths SSCCE:
public class MultiLineList extends JFrame
{
private static final long serialVersionUID = 1L;
public static void main(final String[] args)
{
new MultiLineList();
}
private MultiLineList()
{
setTitle("MultiLineList");
setSize(800, 450);
setResizable(true);
setVisible(true);
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
this.getContentPane().setLayout(new BorderLayout());
final DefaultListModel model = new DefaultListModel();
model.addElement("This is a short text");
model.addElement("This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. ");
model.addElement("This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. ");
final JList list = new JList(model);
list.setCellRenderer(new MyCellRenderer());
this.add(list);
this.getContentPane().invalidate();
this.getContentPane().validate();
}
public class MyCellRenderer extends DefaultListCellRenderer
{
#Override
public Component getListCellRendererComponent(final JList list, final Object value, final int index, final boolean isSelected, final boolean hasFocus)
{
final String text = (String) value;
//create panel
final JPanel p = new JPanel();
p.setLayout(new BorderLayout());
//icon
final JPanel IconPanel = new JPanel(new BorderLayout());
final JLabel l = new JLabel("icon"); //<-- this will be an icon instead of a text
IconPanel.add(l, BorderLayout.NORTH);
p.add(IconPanel, BorderLayout.WEST);
//text
final JTextArea ta = new JTextArea();
ta.setText(text);
ta.setLineWrap(true);
ta.setWrapStyleWord(true);
p.add(ta, BorderLayout.CENTER);
return p;
}
}
}
Edit 1: oops - seeing #Andrew's screenshot, realized that this isn't working as expected, the text is actually longer than shown with this (overlooked an internal comment "PENDING: not working for JList in JScrollPane" ;-) Will dig a bit and delete this answer if I can't make it work soon.
Edit 2: got it - the renderer implementation as shown below is okay, the culprit is the JList with its occasional less than optimal size caching. There are two parts of that
BasicListUI doesn't take into account that resizing the list might require clearing the internal size (actually row height) cache, application code must force it to do so, f.i. in a ComponentListener
list's Scrollable implementation of tracksViewportWidth contains logic which stands in the way (leads to looping stretch-out of the area until it's a single line), subclass to return true.
Code that uses the renderer below:
final JList list = new JList(model) {
/**
* #inherited <p>
*/
#Override
public boolean getScrollableTracksViewportWidth() {
return true;
}
};
list.setCellRenderer(new MyCellRenderer());
ComponentListener l = new ComponentAdapter() {
#Override
public void componentResized(ComponentEvent e) {
// next line possible if list is of type JXList
// list.invalidateCellSizeCache();
// for core: force cache invalidation by temporarily setting fixed height
list.setFixedCellHeight(10);
list.setFixedCellHeight(-1);
}
};
list.addComponentListener(l);
add(new JScrollPane(list));
First answer (a renderer implementation which uses JTextArea as rendering component)
TextArea is a bit tricky in sizing: it needs to get initialized to something reasonable:
public class MyCellRenderer implements ListCellRenderer {
private JPanel p;
private JPanel iconPanel;
private JLabel l;
private JTextArea ta;
public MyCellRenderer() {
p = new JPanel();
p.setLayout(new BorderLayout());
// icon
iconPanel = new JPanel(new BorderLayout());
l = new JLabel("icon"); // <-- this will be an icon instead of a
// text
iconPanel.add(l, BorderLayout.NORTH);
p.add(iconPanel, BorderLayout.WEST);
// text
ta = new JTextArea();
ta.setLineWrap(true);
ta.setWrapStyleWord(true);
p.add(ta, BorderLayout.CENTER);
}
#Override
public Component getListCellRendererComponent(final JList list,
final Object value, final int index, final boolean isSelected,
final boolean hasFocus) {
ta.setText((String) value);
int width = list.getWidth();
// this is just to lure the ta's internal sizing mechanism into action
if (width > 0)
ta.setSize(width, Short.MAX_VALUE);
return p;
}
}
import java.awt.*;
import javax.swing.*;
public class MultiLineList
{
private static final long serialVersionUID = 1L;
public static void main(final String[] args)
{
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new MultiLineList();
}
});
}
private MultiLineList()
{
JFrame f = new JFrame("MultiLineList");
f.setResizable(true);
f.setVisible(true);
f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
f.getContentPane().setLayout(new BorderLayout());
final DefaultListModel model = new DefaultListModel();
model.addElement("This is a short text");
model.addElement("This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. This is a long text. ");
model.addElement("This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. This is an even longer text. ");
final JList list = new JList(model);
list.setCellRenderer(new MyCellRenderer());
f.add(list);
f.pack();
}
public class MyCellRenderer extends DefaultListCellRenderer
{
final JPanel p = new JPanel(new BorderLayout());
final JPanel IconPanel = new JPanel(new BorderLayout());
final JLabel l = new JLabel("icon"); //<-- this will be an icon instead of a text
final JLabel lt = new JLabel();
String pre = "<html><body style='width: 200px;'>";
MyCellRenderer() {
//icon
IconPanel.add(l, BorderLayout.NORTH);
p.add(IconPanel, BorderLayout.WEST);
p.add(lt, BorderLayout.CENTER);
//text
}
#Override
public Component getListCellRendererComponent(final JList list, final Object value, final int index, final boolean isSelected, final boolean hasFocus)
{
final String text = (String) value;
lt.setText(pre + text);
return p;
}
}
}
Related
So i am making a shop system with a gui. I have a menu item that when i press it opens another jframe to input the number of each item sold in a jtextfield, like this:
JPanel salesPanel = new JPanel();
setSize(new Dimension(520,270));
setResizable(false);
setLocation(200,200);
title = new JLabel("<html><u><b>Fill in the number of products sold.</b></u></html>");
salesPanel.setSize(new Dimension(230,30*sw.getProductList().size()));
salesPanel.setLayout(new GridLayout(sw.getProductList().size()+1,3));
...
sw.getProductList().forEach(n ->{
salesPanel.add(new JLabel(Integer.toString(n.getProductID())+":"));
salesPanel.add(new JLabel(Integer.toString(n.getQuantity())));
salesPanel.add(new JLabel(n.getName()));
salesPanel.add(new JTextField());
});
This is how it looks.
Note that sw is the object of the main class which has an ArrayList of the type product which contains the information of each product.
Is there any way that I can text from these JTextFields ? And if not what is another way that I can do this.
EDIT:
in the main ShopWindow class, I have an ArrayList
private ArrayList<Product> productList = new ArrayList<Product>();
class product:
public class Product {
private int productID;
private String name;
private double price;
private int quantity;
private boolean isPerishable;
private double totalProdValue;
...getters and setters for each field
This is a mock solution (only meant to show how to update qty label and clear fields using action listeners)
public class MockFrame {
public static void main(String[] args) {
JFrame frame = new JFrame();
JPanel framePanel = new JPanel();
ProductPanel bananaPanel = new ProductPanel("268", "25", "Bananas");
ProductPanel sugarPanel = new ProductPanel("321", "200", "Sugar");
JPanel buttonPanel = new JPanel();
JButton update = new JButton("Update");
JButton cancel = new JButton("Cancel");
buttonPanel.setSize(400, 30);
update.setSize(50, 20);
cancel.setSize(50, 20);
buttonPanel.add(update);
buttonPanel.add(cancel);
update.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
bananaPanel.setNewQty();
sugarPanel.setNewQty();
}
});
cancel.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
bananaPanel.clearField();
sugarPanel.clearField();
}
});
frame.setSize(400, 400);
framePanel.setLayout(new BoxLayout(framePanel, BoxLayout.PAGE_AXIS));
framePanel.add(bananaPanel);
framePanel.add(sugarPanel);
framePanel.add(buttonPanel);
frame.add(framePanel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
private static class ProductPanel extends JPanel {
private JLabel productId = new JLabel();
private JLabel qty = new JLabel();
private JLabel name = new JLabel();
private JTextField field = new JTextField();
public ProductPanel(String id, String amount, String itemName) {
this.setSize(400, 30);
this.field.setSize(100, 20);
this.field.setColumns(5);
productId.setText(id);
qty.setText(amount);
name.setText(itemName);
this.add(productId);
this.add(qty);
this.add(name);
this.add(field);
}
public void clearField() {
field.setText("");
}
public void setNewQty() {
String newQty = field.getText();
if (newQty != null && !newQty.isBlank()) {
qty.setText(newQty);
}
}
}
}
Main points of this mocked solution:
Use a JPanel to encapsulate a product line item. This will make it easier if you need to remove and/or add product rows.
The product panel contains a method to update qty or clear the fields that will be invokable by the frame buttons (depending on which is clicked).
Simplicity of design - Creating a generic panel for the product eliminate repetitive code.
Obviously, you would have to modify this so that you use the proper layout manager or use absolute positioning to properly aligned components to your liking. Also, you would need to create a Panel for the table header and add the remaining of your products. Also, you may want to break this into public classes and even maybe create a separate class for your frame.
The action listeners could also have a "for-each" loop to update each ProductPanel instead of hard coding each panel individually. That should look something like this:
public void actionPerformed(ActionEvent e) {
JPanel panel = (JPanel)((JButton) e.getSource()).getParent().getParent();
Component[] components = panel.getComponents();
for (Component c : components) {
if (c instanceof ProductPanel) {
((ProductPanel)c).setNewQty();
}
}
}
});
Obviously, your solution will depend on how you decide to encapsulate your components in containers. For this mock, the product panels are inside the frame panel which contains the panels where the buttons were placed. Therefore, I need to get the "grandparent" container for the update and cancel buttons to take advantage of calling the appropriate methods to update and clear in a more dynamic way.
Lastly, you may want to do something more elegant for creating your product panels. For example, you may want to add some factory method to create your product panel instead of having hard-coded product panels like my mock solution. Anyway, I think I demonstrated the solution you were looking for.
UPDATE: If you don't follow Andrew Thompson's recommendation of not using text fields for numeric values, the panel's getNewQty method would need to validate the text obtained to make sure it contains a valid numeric value (which was his point). I would STRONGLY recommend you follow his advice.
I have a JTable for which the renderer returns a JPanel composed of multiple JLabel instances. One of those JLabels can contain HTML used among other things to split the output over multiple lines using <br/> tags.
To show the multiple lines in the table, the renderer calls in the getTableCellRendererComponent method
table.setRowHeight(row, componentToReturn.getPreferredSize().height);
to dynamically update the row height, based on the contents. This only works correctly if componentToReturn indicates a correct preferred size.
It looks however that the getPreferredSize returns bogus values. The preferred height of the returned component is smaller than the sum of the heights of the labels inside the component.
Here is a little program illustrating this behaviour (without using a JTable)
import java.awt.*;
import javax.swing.*;
public class SwingLabelTest {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
LabelPanel renderer = new LabelPanel();
Component component = renderer.getComponent(false);
//asking for a bigger component will not
//update the preferred size of the returned component
component = renderer.getComponent(true);
}
});
}
private static class LabelPanel {
private final JPanel compositePanel;
private final JLabel titleLabel = new JLabel();
private final JLabel propertyLabel = new JLabel();
public LabelPanel() {
JPanel labelPanel = new JPanel();
labelPanel.setLayout(new BoxLayout(labelPanel, BoxLayout.PAGE_AXIS));
labelPanel.add(titleLabel);
labelPanel.add(propertyLabel);
compositePanel = new JPanel(new BorderLayout());
//normally it contains more components,
//but that is not needed to illustrate the problem
compositePanel.add(labelPanel, BorderLayout.CENTER);
}
public Component getComponent( boolean aMultiLineProperty ) {
titleLabel.setText("Title");
if ( aMultiLineProperty ){
propertyLabel.setText("<html>First line<br/>Property: value</html>");
} else {
propertyLabel.setText("Property: value");
}
int titleLabelHeight = titleLabel.getPreferredSize().height;
int propertyLabelHeight = propertyLabel.getPreferredSize().height;
int compositePanelHeight = compositePanel.getPreferredSize().height;
if ( compositePanelHeight < titleLabelHeight + propertyLabelHeight){
throw new RuntimeException("Preferred size of the component returned "
+ "by the renderer is incorrect");
}
return compositePanel;
}
}
}
As I am aware that the previous example is a bit far-fetched, here an example which includes a JTable
import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;
public class SwingTableTest {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
DefaultTableModel tableModel = new DefaultTableModel(0, 1);
JTable table = new JTable(tableModel);
table.setDefaultRenderer(Object.class, new DataResultRenderer());
tableModel.addRow(new Object[]{new Object()});
tableModel.addRow(new Object[]{new Object()});
tableModel.addRow(new Object[]{new Object()});
JFrame testFrame = new JFrame("TestFrame");
testFrame.getContentPane().add(new JScrollPane(table));
testFrame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
testFrame.setSize(new Dimension(300, testFrame.getPreferredSize().height));
testFrame.setVisible(true);
}
});
}
private static class DataResultRenderer implements TableCellRenderer {
private final JPanel compositePanel;
private final JLabel titleLabel = new JLabel();
private final JLabel propertyLabel = new JLabel();
public DataResultRenderer() {
JPanel labelPanel = new JPanel();
labelPanel.setOpaque(false);
labelPanel.setLayout(new BoxLayout(labelPanel, BoxLayout.PAGE_AXIS));
labelPanel.add(titleLabel);
labelPanel.add(propertyLabel);
compositePanel = new JPanel(new BorderLayout());
//normally it contains more components,
//but that is not needed to illustrate the problem
compositePanel.add(labelPanel, BorderLayout.CENTER);
}
#Override
public Component getTableCellRendererComponent(
JTable table, Object value, boolean isSelected,
boolean hasFocus, int row, int column) {
titleLabel.setText("Title");
if ( row == 2 ){
propertyLabel.setText("<html>Single property: value</html>");
} else {
String text = "<html>";
text += "First property<br/>";
text += "Second property<br/>";
text += "Third property:value";
text += "</html>";
propertyLabel.setText(text);
}
int titleLabelHeight = titleLabel.getPreferredSize().height;
int propertyLabelHeight = propertyLabel.getPreferredSize().height;
int compositePanelHeight = compositePanel.getPreferredSize().height;
if ( compositePanelHeight < titleLabelHeight + propertyLabelHeight){
throw new RuntimeException("Preferred size of the component returned "
+ "by the renderer is incorrect");
}
table.setRowHeight(row, compositePanel.getPreferredSize().height);
return compositePanel;
}
}
}
I am looking for a way to update the row height of the table to ensure that the multi-line content is completely visible, without knowing up front how many lines each row will contain.
So either I need a solution to retrieve the correct preferred size, or my approach is completely wrong and then I need a better one.
Note that the above examples are simplified. In the real code, the "renderer" (the code responsible for creating the component) is decorated a few times. This means that the outer renderer is the only with access to the JTable, and it has no knowledge about what kind of Component the inner code returns.
Because setRowHeight() "Sets the height, in pixels, of all cells to rowHeight, revalidates, and repaints," the approach is unsound. Absent throwing an exception, profiling shows 100% CPU usage as an endless cascade of repaints tries to change the row height repeatedly. Moreover, row selection becomes unreliable.
Some alternatives include these:
Use TablePopupEditor to display multi-line content on request from a TableCellEditor.
Update an adjacent multi-line panel from a TableModelListener, as shown here.
I need to write an applet that converts char values to ascii values. Right now I'm just trying to get the layout of the applet right, but for some reason my JTextFields are showing up very strangely and I don't know how to go about fixing it. One is very large and the other is extremely small.
I had some trouble getting GridLayout to work the way I wanted, and I have some feeling that the problems have something to do with that but I don't know for sure.
Here's the code:
import javax.swing.*;
import java.awt.*;
import java.util.*;
import java.awt.event.*;
public class Ex1_2 extends JApplet implements ActionListener
{
private JTextField charInput;
private JLabel display1;
private JLabel dummy;
private JLabel display2;
private JLabel welcome;
private JTextField ascii;
private JLabel error;
Container pane = getContentPane();
public void init()
{
pane.setLayout(new BorderLayout());
pane.setBackground(Color.orange);
display1 = new JLabel("Character", SwingConstants.CENTER);
display2 = new JLabel("ASCII code", SwingConstants.CENTER);
dummy = new JLabel("", SwingConstants.CENTER);
dummy.setBackground(Color.orange);
welcome = new JLabel("Char <-> ASCII converter", SwingConstants.CENTER);
welcome.setForeground(Color.blue);
pane.add(welcome, BorderLayout.NORTH);
pane.add(dummy, BorderLayout.SOUTH);
//charInput.addActionListener(this);
add(addMiddle());
}
JPanel addMiddle()
{
JPanel p = new JPanel();
p.setLayout(new GridLayout(0, 2, 10, -5));
p.setBackground(Color.green);
p.add(display1, BorderLayout.SOUTH);
p.add(display2, BorderLayout.SOUTH);
p.add(dummy);
p.add(addInnerLeft());
p.add(addInnerRight());
p.add(dummy);
return p;
}
JPanel addInnerLeft()
{
JPanel p2 = new JPanel(new GridLayout(0, 2));
p2.setBackground(Color.yellow);
pane.add(p2);
charInput = new JTextField("");
charInput.setForeground(Color.black);
//p2.add(charInput);
return p2;
}
JPanel addInnerRight()
{
JPanel p3 = new JPanel();
p3.setBackground(Color.yellow);
ascii = new JTextField("");
ascii.setForeground(Color.black);
//p3.add(ascii);
return p3;
}
public void actionPerformed(ActionEvent e)
{
}
}
A quick fix:
Consider setting your JTextFields's column property. For instance, if you use:
ascii = new JTextField("", 5);
your ascii JTextField now gets some preferred size width.
A better long-term fix:
Study, learn and use the layout managers to better advantage.
Note that a problem with JApplets is that the size is specified by the HTML code and not by the layout managers (as far as I understand things), and so you must take care to make sure that the GUI's are sized big enough.
e.g., with layouts, I got this:
The second text field is sized that way because you initialized it:
ascii = new JTextField("");
This represents that the text field has a string value for its name where the length of the string is zero. The text field is being sized automatically according to the text it contains. Since it contains a string with zero length, the size of the text field is so small.
You could use the setColumns(int columns) method on the text field to give it a fixed width, so that it can get a preferred size.
I have a situation like this.
I have scrollpane whose viewportView is a JPanel
And that JPanel has the layout as BoxLayout. In this panel I add one class which extends JPanel and that class contains JComponents.
So while running an application, the JComponents are shown in the JScrollPane.
This is how my ScrollPane is formed.
The problem here is, When the data exceeds more than around 750 rows, The scrollbar starts giving problems.
When scrolling up or down by mouse wheel, scroll doesnot move smoothly, It suddenly stops in the middle and again starts, say it has a jerky movement.
my Question is how can i get the smooth mouse movement in this scenario.
My scrollPane is like this
public JScrollPane getScrollPane() {
if (scrollPane == null) {
scrollPane = new JScrollPane();
scrollPane.setSize(new Dimension(1000, 433));
scrollPane.setLocation(new Point(10, 10));
scrollPane.setColumnHeaderView(getHeaderOfRowPanel());
scrollPane
.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.setViewportView(getScrollPanel());
scrollPane
.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
scrollPane.getVerticalScrollBar().setUnitIncrement(
unitIncrement);
}
return scrollPane;
}
private JPanel getScrollPanel() {
if (scrollPanel == null) {
scrollPanel = new JPanel();
scrollPanel.setBorder(null);
scrollPanel.setLayout(new BoxLayout(getScrollPanel(),
BoxLayout.Y_AXIS));
}
return scrollPanel;
}
private class RowPanel extends JPanel {
//My components are here ..
//I add this Panel in scrollPanel
}
Have look at JScrollBar.setUnitIncrement, beacuse bunch of JPanels in the JScollPane has un_natural scrolling in compare with JList, JTable or JTextArea
example
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class JScrollBarUnitIncrement {
public static void main(String[] args) {
final JFrame f = new JFrame("");
JPanel panel = new JPanel();
panel.setLayout(new GridLayout(2000, 1));
for (int i = 0; i != 2000; i++) {
JButton btn = new JButton("Button 2");
panel.add(btn);
}
final JScrollPane sPane = new JScrollPane(panel);
final int increment = 50;
sPane.getVerticalScrollBar().setUnitIncrement(increment);
KeyStroke kUp = KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0);
KeyStroke kDown = KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0);
sPane.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(kUp, "actionWhenKeyUp");
sPane.getActionMap().put("actionWhenKeyUp", new AbstractAction("keyUpAction") {
private static final long serialVersionUID = 1L;
public void actionPerformed(ActionEvent e) {
final JScrollBar bar = sPane.getVerticalScrollBar();
int currentValue = bar.getValue();
bar.setValue(currentValue - increment);
}
});
sPane.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(kDown, "actionWhenKeyDown");
sPane.getActionMap().put("actionWhenKeyDown", new AbstractAction("keyDownAction") {
private static final long serialVersionUID = 1L;
public void actionPerformed(ActionEvent e) {
final JScrollBar bar = sPane.getVerticalScrollBar();
int currentValue = bar.getValue();
bar.setValue(currentValue + increment);
}
});
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(sPane);
f.pack();
SwingUtilities.invokeLater(new Runnable() {
public void run() {
f.setVisible(true);
}
});
}
private JScrollBarUnitIncrement() {
}
}
It is never good to populate such huge no. of rows in JScrollPane. Because, the visible portion is only around let's say 20 to 30 rows in viewport depending on the height of the scrollpane and the height of your RowPanel. So, why to populate such huge rows at once ? The problem with the smoothness is because there might be exception (see the console ). So, resolve this, I see two options for you. One is to use pagination and another is to allow users to enter some search criteria to filter out the unwanted records.
As #mKorbel notes, both JTable and JList implement Scrollable for convenient scroll increments, and they both use the flyweight pattern for rendering speed. If you can't use either component directly, you can still use the patterns. The tutorial includes Scrollable examples, and there's a CellRendererPane example here.
Just wondering if you could help wanting to produce an activity stream in Java, the idea was to have a JLabel and text area followed by a divider be displayed on a screen and then repeated X amount of times according to what data was in a database.
What I was wondering is how could I possibly repeat the placing the jlabel, text area, and diveder on the screen above the last rendered objects on the fly and all displayed correctly no matter the size of the text area of each set of object sort of like the image below.
Hope I made it clear as I could thanks
Just provide your own version of a JPanel containing all these things and place them in a scrollpane that will care about having a long list of these panels..
class MyPanel extends JPanel
{
ImageIcon icon;
JTextArea textArea;
MyPanel(ImageIcon icon, String text)
{
this.icon = icon;
this.setPreferredSize(/*max size of your panel */)
textArea = new JTextArea(10, 50);
textArea.append(text);
//the default manager will be a flow layout for single jpanels
this.add(icon);
JScrollPane sp = new JScrollPane(textArea);
sp.setPreferredSize(new Dimension(/* size of your text label */));
this.add(new JScrollPtextArea);
}
}
class MyContainer extends JFrame
{
JPanel container;
JScrollPane spContainer;
MyContainer()
{
container = new JPanel()
container.setGridLayout(100,1); //100 elements max
spContainer = new JScrollPane(container);
spContainer.setPreferredSize(/* max size of whole thing */)
this.add(spContainer);
pack();
}
void addElement(MyPanel panel)
{
container.add(panel);
this.pack();
}
}
It's not fully working (I just wrote it) but it should give you the idea..