I've thoroughly searched for an answer to my question and tried multiple things but none of these things worked for me.
I have a button that opens a JDialog allowing the user to attribute and change colors for three types of objects/constraints.
The JDialog consists of 2 JPanels, the first containing another 3 JPanels for all three types of objects, and the second one for the OK/Cancel buttons.
My problem is in the third type of objects so-called "Label constraints".
This third type of objects can have sub-objects which are added dynamically to a JPanel as the user creates them and consist of a name and a button for changing the color of the object.
This is the method that creates a JPanel that containts text and a button for choosing the color of the object and adds it to the labelColorConstraintPanel which is a field of the class. This method is called in another method responsible for creating the objects.
/**
* Add the last created label constraint class name(number) and its color
* button to the panel labelColorConstraintPanel. The button allows user to
* choose the label constraint class color.
**/
protected void createLabelColorConstraintsPanel() {
// labelColorConstraintPanel
JPanel classNameButtonPanel = new JPanel(new GridLayout(0, 2));
// classNameButtonPanel.setPreferredSize(new Dimension(15, 20));
classNameButtonPanel.setBorder(BorderFactory.createEmptyBorder(3, 3, 3, 3));
classNameButtonPanel.add(new JLabel("Class " + labelClassesCount + ":"));
jb_labelConstraintClassChooseColor.get(labelClassesCount - 1).addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
JButton lblClassColorButtonClicked = (JButton) event.getSource();
int buttonIndex = (int) lblClassColorButtonClicked.getClientProperty("index");
chooseLabelClassColor(buttonIndex);
}
});
classNameButtonPanel.add(jb_labelConstraintClassChooseColor.get(labelClassesCount - 1));
labelColorConstraintPanel.add(classNameButtonPanel);
}
The labelColorConstraintPanel is attached to a JScrollPane which is attached to another JPanel for this third type of objects - Label constraints.
My problem is that the JScrollBar on the JScrollPane won't appear.
However I read that setting the preferredSize of the JPanel within the JScrollPane to a size bigger than this second will make the vertical bar appear (see commented code lines in method chooseConstraintsColors).
In this way I managed to make the bar show, but I have two other problems.
The first one: first buttons added stretch on the total of the JPanel creating enormous buttons.
The second one: the more buttons I add, they're resized and at some point the rows get "crowded".
Finally I suppose these 2 problems represent the same problem, but however I cant seem to find the solution.
Either there is another way to show the JScrollBar without setting the preferredSize(), or there is a way to dynamically increase the size of the JPanel as we add new objects to it with fixed size.
Here is the main method that creates the JDialog window:
/** Opens a JDialog for choosing the Constraints Colors **/
protected void chooseConstraintColors() {
jd_colorsChooser = new JDialog((Frame) this.getTopLevelAncestor(), "Choose Constraints Colors", true);
jd_colorsChooser.getRootPane().setBorder(BorderFactory.createEmptyBorder(3, 3, 3, 3));
jd_colorsChooser.setLayout(new BorderLayout());
JPanel constraintsPanel = new JPanel(new BorderLayout());
JPanel mlConstraintsPanel = new JPanel();
JPanel clConstraintsPanel = new JPanel();
JPanel lblConstraintsPanel=new JPanel(new GridLayout(0,1));
JScrollPane lblConstraintsPane = new JScrollPane(labelColorConstraintPanel,
ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS, ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
lblConstraintsPane.setPreferredSize(new Dimension(130,130));
TitledBorder lblcBorder = BorderFactory.createTitledBorder(
BorderFactory.createEtchedBorder(EtchedBorder.LOWERED), "Label Constraints Color", TitledBorder.LEFT,
TitledBorder.TOP);
lblConstraintsPane.setBorder(lblcBorder);
// must-link constraints panel
mlConstraintsPanel.setLayout(new BorderLayout());
TitledBorder mlcBorder = BorderFactory.createTitledBorder(
BorderFactory.createEtchedBorder(EtchedBorder.LOWERED), "Must-Link Constraints Color",
TitledBorder.LEFT, TitledBorder.TOP);
mlConstraintsPanel.setBorder(mlcBorder);
jb_mustLinkChooseColor.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
chooseMustLinkColor();
}
});
mlConstraintsPanel.add(jb_mustLinkChooseColor, BorderLayout.CENTER);
// cannot-link constraints panel
clConstraintsPanel.setLayout(new BorderLayout());
TitledBorder clcBorder = BorderFactory.createTitledBorder(
BorderFactory.createEtchedBorder(EtchedBorder.LOWERED), "Cannot-Link Constraints Color",
TitledBorder.LEFT, TitledBorder.TOP);
clConstraintsPanel.setBorder(clcBorder);
jb_cannotLinkChooseColor.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
chooseCannotLinkColor();
}
});
clConstraintsPanel.add(jb_cannotLinkChooseColor, BorderLayout.CENTER);
// label constraints panel
labelColorConstraintPanel.setPreferredSize(new Dimension(131,131));
lblConstraintsPanel.add(lblConstraintsPane);
constraintsPanel.add(mlConstraintsPanel, BorderLayout.NORTH);
constraintsPanel.add(clConstraintsPanel, BorderLayout.CENTER);
constraintsPanel.add(lblConstraintsPanel, BorderLayout.SOUTH);
// button panel
JPanel buttonPanel = new JPanel();
JButton ok = new JButton("OK");// update color changes on ok, update
// only fields that have changed
ok.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent event) {
if (mustLinkColorTemp != null && mustLinkColorTemp != mustLinkColor) {
mustLinkColor = mustLinkColorTemp;
jb_mustLinkChooseColor.setBackground(mustLinkColor);
}
if (cannotLinkColorTemp != null && cannotLinkColorTemp != cannotLinkColor) {
cannotLinkColor = cannotLinkColorTemp;
jb_cannotLinkChooseColor.setBackground(cannotLinkColor);
}
for (int i = 0; i < labelClassesCount; i++) {
if (labelConstraintColorTemp.get(i) != null
&& labelConstraintColorTemp.get(i) != labelConstraintColor.get(i)) {
labelConstraintColor.set(i, labelConstraintColorTemp.get(i));
jb_labelConstraintClassChooseColor.get(i).setBackground(labelConstraintColor.get(i));
}
}
jd_colorsChooser.dispose();
}
});
// exit dialog on cancel
JButton cancel = new JButton("Cancel");
cancel.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
jb_mustLinkChooseColor.setBackground(mustLinkColor);
jb_cannotLinkChooseColor.setBackground(cannotLinkColor);
for (int i = 0; i < labelClassesCount; i++) {
jb_labelConstraintClassChooseColor.get(i).setBackground(labelConstraintColor.get(i));
}
jd_colorsChooser.dispose();
}
});
buttonPanel.add(ok);
buttonPanel.add(cancel);
jd_colorsChooser.add(constraintsPanel, BorderLayout.NORTH);
jd_colorsChooser.add(buttonPanel, BorderLayout.SOUTH);
jd_colorsChooser.setPreferredSize(new Dimension(270, 270));
jd_colorsChooser.pack();
jd_colorsChooser.setLocationRelativeTo(null);
jd_colorsChooser.setVisible(true);
}
P.S: As I'm new to StackOverflow I cant really upload pictures, but here is a description of the pictures:
Case1: A JDialog with 3 Panels and a OK and a Cancel button.
If setPreferredSize not used, buttons are added in the third JPanel one after another without the scrollbar appearing.
Case2: setPrefferedSize() used, a scroll bar appears with first button stretched over the size of the JPanel, as we add more buttons the rows with the buttons of the JPanel get crowded.
