Develop Reference

Java : JTree and BasicTreeUI reference doesn't show scrollbars

Working with the JTreeWithScrollbar example, but scaled it back significantly to focus on the issue.
The original code would have the vertical scrollbars appear as needed.
Here, there is plenty of space and no scrollbars are needed.
If the panel is moved enough, the scrollbar will appear.
Once the following line of code was added, the scrollbars stopped appearing.
tree.setUI(new MyTreeUI());
Notice no scrollbar.
If the above line of code is commented out, the vertical scrollbar appears.
Checking the documentation for BasicTreeUI and there isn't anything related to showing/hiding scrollbars.
2 Questions
1 - When utilizing the BasicTreeUI object, what is required to ensure the scrollbars still function?
2 - Why is it the Horizontal scrollbar never appears even if the line of code is commented out?
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTree;
import javax.swing.plaf.basic.BasicTreeUI;
import javax.swing.tree.DefaultMutableTreeNode;
import java.awt.Dimension;
public class JTreeWithScrollbar extends JPanel {
private JEditorPane htmlPane;
private JTree tree;
public JTreeWithScrollbar()
{
//Create the nodes.
DefaultMutableTreeNode top = new DefaultMutableTreeNode("The Java Series");
DefaultMutableTreeNode book1Node = new DefaultMutableTreeNode("Book 1");
DefaultMutableTreeNode book2Node = new DefaultMutableTreeNode("Book 2");
top.add(book1Node);
top.add(book2Node);
tree = new JTree(top);
tree.setUI(new MyTreeUI()); ///Comment out this line of code and the vertical scrollbar appears.
JScrollPane treeView = new JScrollPane(tree);
JScrollPane htmlView = new JScrollPane(htmlPane);
JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
splitPane.setTopComponent(treeView);
splitPane.setBottomComponent(htmlView);
Dimension minimumSize = new Dimension(100, 50);
htmlView.setMinimumSize(minimumSize);
splitPane.setDividerLocation(100);
splitPane.setPreferredSize(new Dimension(500, 300));
add(splitPane);
}
public static void main(String[] args)
{
//Create and set up the window.
JFrame frame = new JFrame("TreeDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel jp = new JPanel();
jp.add(new JTreeWithScrollbar());
frame.add(jp);
//Display the window.
frame.pack();
frame.setVisible(true);
}
private static class MyTreeUI extends BasicTreeUI
{
public MyTreeUI()
{
super();
}
#Override
protected void updateCachedPreferredSize() {
treeState.invalidateSizes();
tree.treeDidChange();
}
}
}

When utilizing the BasicTreeUI object, what is required to ensure the scrollbars still function?
As shown in the minimal example below, BasicTreeUI correctly shows each scroll bar when needed; resize the frame to see the effect.
Why does the horizontal scrollbar never appear even if the line of code is commented out?
After pack() the frame has been resized to adopt the preferred size of it content. Making the frame slightly smaller illustrates the effect. Your example adds the tree to a JPanel having a default FlowLayout which ignores preferred sizes; the example below adds the tree to the center of the frame's default BorderLayout which responds to preferred sizes.
I am assuming the updateCachedPreferredSize() must be doing other stuff behind the scenes…
Exactly. Each invocation of updateCachedPreferredSize() updates the component's preferred size to reflect any change in state (resize, expand, etc.); when the preferred size exceeds the viewport size, the scroll bars appear. As you observed, invoking super.updateCachedPreferredSize() allows normal operation, and any further customization must preserve that functionality.
In addition,
Expand rows as need like this.
Construct and manipulate Swing GUI objects only on the event dispatch thread.
Don't use setSize() when you really mean to override getPreferredSize() or illustrates a resize effect; more here.
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.plaf.basic.BasicTreeUI;
public class JTreeWithScrollbar {
public static void main(String[] args) {
EventQueue.invokeLater(() -> {
//Create and set up the window.
JFrame frame = new JFrame("TreeDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JTree tree = new JTree(); //default model
for (int i = 0; i < tree.getRowCount(); i++) {
tree.expandRow(i);
}
tree.setUI(new MyTreeUI());
frame.add(new JScrollPane(tree));
//Display the window.
frame.pack();
frame.setSize(frame.getWidth() - 10, frame.getHeight() - 100);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
});
}
private static class MyTreeUI extends BasicTreeUI {
}
}

Tool tip in gui not displaying?

I am using the .setToolTipText component so that the text "This will show up when you hover over it" shows up when the mouse is hovered over the window. Currently, everything else is working, except for the tooltip. Right now the tool tip only displays when hovered above the words, how do I make it display whenever I hover over the window itself? This is the code:
Here is the main class:
import javax.swing.JFrame;
class evenmoregui{
public static void main (String[ ] args){
moregui guiobject = new moregui();
guiobject.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Makes the program terminate when the x is clicked
guiobject.setSize(275,180); //This is the size
guiobject.setVisible(true); //Means it should show up, actually puts the window on screen
}
}
Here is the class with the actual .setToolTip part:
import java.awt.FlowLayout; //Make it so the windows don't overlap, it just formats the windows properly
import javax.swing.JFrame; //Gives you all the windows features in the window, like minimize
import javax.swing.JLabel; //Allows text and simple images on window
public class moregui extends JFrame { //JFrame gives you all the basic windows features.
private JLabel item1;
public moregui(){ //Constructor
super("This is the title bar"); //These are all imported methods
setLayout(new FlowLayout()); //Gives default layout
item1 = new JLabel("This is a sentence"); //Text on the screen
item1.setToolTipText("This will show up when you hover over it");
add(item1); //Adds item1 into window
}
}

Try adding getRootPane().setToolTipText("String");
this will make sure that the tool tip is shown when hovered over JFrame
import java.awt.FlowLayout;
import javax.swing.JFrame; window, like minimize
import javax.swing.JLabel;
public class moregui extends JFrame{
private JLabel item1;
public moregui(){ //Constructor
super("This is the title bar"); //These are all imported methods
getRootPane().setToolTipText("Hovering over window");
setLayout(new FlowLayout()); //Gives default layout
item1 = new JLabel("This is a sentence"); //Text on the screen
item1.setToolTipText("This will show up when you hover over it");
add(item1); //Adds item1 into window
}
}

This is a correct code. Try hovering over it longer.
JPanel panel = new JPanel();
panel.setToolTipText("ToolTIp");
contentPane.add(panel, BorderLayout.NORTH);
JLabel lblLabel = new JLabel("Label");
panel.add(lblLabel);
Let me know if you ran into any more problems.

Adding onResizeListener to JButton

I have a window(JFrame) which contains special types of JButtons (my own class of buttons which extend JButton). That window suppose to resize itself when the button size is changing(in example when I click on the button its font size increases and the whole size of JButton too).
I do not want make JFrame fit the buttons, but let me decide how big the window should be, so pack() is no solution.
I was thinking about a kind of component listner which would resize window on button size change but I could not find anything.
Code example(working, click the button):
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JOptionPane;
public class ResizingButton extends JButton {
public ResizingButton(String txt) {
super();
setText(txt);
addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
int newFontSize = getFont().getSize() + 1;
setFont(new Font(Font.SANS_SERIF, Font.PLAIN, newFontSize));
FontMetrics metrics = getFontMetrics(getFont());
int width = metrics.stringWidth(getText());
int height = metrics.getHeight();
Dimension newDimension = new Dimension(width + 40, height + 10);
setPreferredSize(newDimension);
setBounds(new Rectangle(getLocation(), getPreferredSize()));
}
});
}
}
import java.awt.FlowLayout;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
#SuppressWarnings("serial")
public class Zadanie2 extends JFrame {
JButton jb1, jb2;
public Zadanie2() {
createGUI();
}
private void createGUI() {
setSize(200, 80);
setLayout(new FlowLayout());
add(new ResizingButton("tekst"));
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public static void main(String[] args) {
new Zadanie2();
}
}

That window suppose to resize itself when the button size is changing(in example when I click on the button its font size increases and the whole size of JButton too).
Override the getPreferredSize() of your custom button.
I do not want make JFrame fit the buttons, but let me decide how big the window should be, so pack() is no solution.
Now when you invoke pack() the frame will be resized taking into account the new preferred size of the button.
I was thinking about a kind of component listner which would resize window on button size change but I could not find anything.
The ComponentListener has a componentResized() event. So you would add the listener to the button. You would only use this approach if your automatic resizing code is different then just using pack().

see ComponentListener
ComponentListener firing one event per one pixel on resize
add Swing Timer if event to the Swing GUI will be done only once time, if resize ended
Swing Timer with small dealy 350-500ms, if resize still continue then to test Timer.isRunning, if return true then only Timer#restart(),

Understanding layout managers -- I'm not, please enlighten me

I'm just not understanding why things are being resized when I call the validate() and repaint() methods. I'm struggling to understand this. Essentially, my program is meant to display like this. I have a main frame into which I plug the various JPanels that I'm extending for the various functions of my photo album. The class below is the NewAlbum class that is supposed to allow the user to select files and make a new album out of them.
The code for choosing files works nicely. Once the files are selected, the change to the NewAlbum panel should be the select files button is replaced by a done button. Under the done button is a JSplitPane with the horizontal splitter just off center with the right side being larger than the left. The left side will eventually have a thumbnail of each photo as metadata about the photo is entered into the right side.
The right side pane is to be a JScrollPane with a single JPanel which has, in a grid form, the 4 entries that the user is asked for data about. After adding everything, the dimensions are where I want them to be, but when I call the validate/repaint combination the dimensions become "messed up." I'm pretty sure it's because I'm not understanding how the default layout managers for the various classes I'm using, or extending. Please help me understand. Also, tell me if the GridBagLayout is what I want, or if a different one is what I'm looking for.
The NewAlbum code is below.
I apologize for the uncompilable code. I figured that you'd be able to just look at the class and tell me, "Oh, yeah, this is the problem." Below is compilable and does demonstrate the problem. Once the files are selected, the split pane window is too thin and too long. I want it to fit inside the frame. Actually, it should fit inside the JPanel which is inside the JFrame.
Thanks,
Andy
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.Iterator;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
class Main extends JFrame {
static JPanel transientPanel = null;
public Main() {
super();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(640, 480);
JMenuBar menuBar = new JMenuBar();
JMenu menu = new JMenu("Example");
JMenuItem albumMenu = new JMenuItem("New Album");
albumMenu.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
transientPanel = new NewAlbum();
add(transientPanel);
validate();
repaint();
}
});
menu.add(albumMenu);
menuBar.add(menu);
setJMenuBar(menuBar);
validate();
}
public static void main(String[] args) {
final Main m = new Main();
m.setVisible(true);
}
}
/**
* #description NewAlbum is the window that is presented to the user
* to select new photographs for the album. Once selected, the user
* will be presented a form, of sorts, to complete the metadata for this
* album.
* #author Andy
*/
class NewAlbum extends JPanel {
JButton selectFiles;
JButton done;
JButton nextButton = new JButton("Next Image");
ArrayList<File> filesArray;
JSplitPane splitWindow = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, true);
JScrollPane scrollWindow;
JPanel rightSidePanel = new JPanel();
JPanel leftSidePanel = new JPanel();
JLabel subjectLabel = new JLabel("Image subject:");
JLabel locationLabel = new JLabel("Image location:");
JLabel commentLabel = new JLabel("Comments:");
JLabel dateLabel = new JLabel("Date (mm/dd/yyyy):");
JTextField subjectText = new JTextField(25);
JTextField locationText = new JTextField(25);
JTextArea commentText = new JTextArea(4, 25);
JTextField dateText = new JTextField(10);
public NewAlbum() {
super();
selectFiles = new JButton("Select Photos");
selectFiles.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
selectFilesForAlbum();
}
});
add(selectFiles);
}
private void configureRightPanel() {
int jPanelX = getParent().getWidth();
int jPanelY = getParent().getHeight() - 30; // this should account for buttons
// now, resize this panel so that it will be the right size for the split pane
jPanelX = jPanelX - (int)(jPanelX * .31);
rightSidePanel.setSize(jPanelX, jPanelY);
rightSidePanel.add(subjectLabel);
rightSidePanel.add(subjectText);
rightSidePanel.add(locationLabel);
rightSidePanel.add(locationText);
rightSidePanel.add(commentLabel);
rightSidePanel.add(commentText);
rightSidePanel.add(dateLabel);
rightSidePanel.add(dateText);
rightSidePanel.add(nextButton);
// iterate over the photos selected, make bogus info for now
}
private ArrayList<File> makeFileIntoArrayList(File[] f) {
ArrayList<File> a = new ArrayList<File>();
a.addAll(Arrays.asList(f));
return filesArray = a;
}
/**
* selectFilesForAlbum
* This method is private to the NewAlbum class. It is the handler for
* when the user clicks on the "select photos" button. When the function
* executes, it displays the JFileChooser so that the user may select
* the desired photos. The files selected are assigned to a class variable
* of type File[] which is used by the enterPhotoInfo method.
*
* #return void
*/
private void selectFilesForAlbum() {
JFileChooser jfc = new JFileChooser();
jfc.setMultiSelectionEnabled(true);
jfc.showOpenDialog(this);
makeFileIntoArrayList(jfc.getSelectedFiles());
changeButtonToDone();
enterPhotoInfo();
// TODO write the photo album to the disk
}
private void changeButtonToDone() {
remove(selectFiles);
done = new JButton("Done");
add(done);
// by the time this gets called, we'll have a parent container
getParent().validate();
getParent().repaint();
}
private void enterPhotoInfo() {
splitWindow.setSize(this.getWidth(), this.getHeight() - 30);
// remove when the left side panel actually has something
Dimension iewDims = splitWindow.getSize();
int leftX = iewDims.width - (int)(iewDims.width * .69);
int leftY = iewDims.height;
leftSidePanel.setSize(leftX, leftY);
configureRightPanel();
scrollWindow = new JScrollPane(rightSidePanel);
scrollWindow.setSize(rightSidePanel.getSize());
splitWindow.setRightComponent(scrollWindow);
splitWindow.setLeftComponent(leftSidePanel);
splitWindow.setDividerLocation(.31);
System.out.println("Printing dimensions of before validate/repaint: this, splitWindow, scrollWindow, LSP, RSP");
debugPrintDimensions(this);
debugPrintDimensions(splitWindow);
debugPrintDimensions(scrollWindow);
debugPrintDimensions(leftSidePanel);
debugPrintDimensions(rightSidePanel);
//infoEntryWindow.add(infoScroller);
this.add(splitWindow);
this.validate();
this.repaint();
System.out.println("Printing dimensions of: this, splitWindow, scrollWindow, LSP, RSP");
debugPrintDimensions(this);
debugPrintDimensions(splitWindow);
debugPrintDimensions(scrollWindow);
debugPrintDimensions(leftSidePanel);
debugPrintDimensions(rightSidePanel);
}
private void debugPrintDimensions(Container c) {
System.out.println("DEBUG: Containers (x,y): (" +
String.valueOf(c.getWidth()) +
"," +
String.valueOf(c.getHeight()) +
")");
}
}

Also, tell me if the GridBagLayout is what I want, or if a different one is what I'm looking for.
You use the appropriate layout manager for the job. This can also mean using different layout managers on different panels.
splitWindow.setSize(this.getWidth(), this.getHeight() - 30);
You should NEVER use setSize(). That is the job of the layout manager, to determine the size of the component based on the rules of the layout manager.
All components have a preferred size which is used by the layout manager. At times you can use the setPreferredSize() to change the default.

By selecting a LayoutManager, you are handing over control of the layout to that layout manager. You can give the LayoutManager hints via layout constraints and restrictions by setting the preferred dimensions on the components you are arranging, but essentially, the layout manager will call the shots.
With GridBagLayoutManager you can achieve almost anything with constraints and component dimension settings, but it can still be tricky to get right. Try setting the preferred size on your components.
I used to use GridBagLayoutManager for everything, but then I came across MigLayout which really is a huge step forward in terms of easy configuration and layout consistency. I recommend you give it a look.

How to make JTabbedPane autoresize to fit page dimensions?

I have only JTabbedPane inside JFrame. JTabbedPane sets its dimensions to biggest page width/height.
As pages has different size is it possible to force JTabbedPane to change its dimensions when selecting other page?
http://grab.by/3hIg
Top one is how it behave now and bottom one is how i want it to behave (i resized frame by hand)

This is fairly simple. It involves dynamic calculation of differences between your pages dimensions and the using them to force preferred size on you JTabbedPane. I did a quick experiment and it worked. So instead of putting a lot of text here - here is the code. It is not perfect but you should get an idea. Questions are welcome, of course.
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class Test {
private static int maxW = 0;
private static int maxH = 0;
public static void main(String[] args) {
final JFrame f = new JFrame();
final JTabbedPane tabs = new JTabbedPane();
tabs.add( createPanel(Color.RED, 100, 100), "Red");
tabs.add( createPanel(Color.GREEN, 200, 200), "Green");
tabs.add( createPanel(Color.BLUE, 300, 300), "Blue");
final Dimension originalTabsDim = tabs.getPreferredSize();
tabs.addChangeListener(new ChangeListener() {
#Override
public void stateChanged(ChangeEvent e) {
Component p = ((JTabbedPane) e.getSource()).getSelectedComponent();
Dimension panelDim = p.getPreferredSize();
Dimension nd = new Dimension(
originalTabsDim.width - ( maxW - panelDim.width),
originalTabsDim.height - ( maxH - panelDim.height) );
tabs.setPreferredSize(nd);
f.pack();
}
});
f.setContentPane(tabs);
f.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
private static final JPanel createPanel( Color color, int w, int h ) {
JPanel p = new JPanel();
p.setBackground(color);
p.setPreferredSize( new Dimension(w, h));
maxW = Math.max(w, maxW);
maxH = Math.max(h, maxH);
return p;
}
}

I think another option is to dynamically change the panels of each tab when the tab is selected:
install a listener on JTabbedPane selection
install an empty panel on every tab but the selected tab by default (that contains the real panel for that tab)
in the selection listener:
remove the panel from the previously selected tab (ie, replace it with an empty panel)
change the empty panel by the real panel in the newly selected tab
call pack() on the window/dialog containing the JTabbedPane
Disclaimer: I haven't tested this approach but I believe it should work according to what you want.
Please also note that dynamically changing the size of the dialog based on the selected tab is not very user-friendly from a pure GUI viewpoint.

How about this?
tabbedPane.addChangeListener(new ChangeListener(){
#Override
public void stateChanged(ChangeEvent arg0) {
Component mCompo=tabbedPane.getSelectedComponent();
tabbedPane.setPreferredSize(mCompo.getPreferredSize());
BasicFrame.this.pack();
}
});