I want a ListSelectionListener event to change a JPanel. I know it is getting fired properly because the print statement is working, however the panel does not change at all.
DefaultListModel leftList = new DefaultListModel();
JList order = new JList(leftList);
order.addListSelectionListener(this);
JPanel configPanel = new JPanel();
public void valueChanged(ListSelectionEvent e) {
if(e.getValueIsAdjusting()){
int index = order.getSelectedIndex();
System.out.println(leftList.getElementAt(index).toString());
configPanel.removeAll();
configPanel.repaint();
configPanel.add(new JLabel("nice"));
configPanel.repaint();
}
}
I threw in the second repaint simply because I was out of things to try, however it still did not work.
When you add components to a visible GUI the basic logic is:
panel.remove(...);
panel.add(...);
panel.revalidate();
panel.repaint();
Basically all components have a size of (0, 0) when they are created so there is nothing to paint. You need to invoke revalidate() so the layout manager can give the components a size and location on the panel.
Related
I have a JPanel. Inside Panel I have kept one JLabel and three JCheckBox.
I want to keep all the checkBox in one line after JLabel. Here is the sample code and some screenshots.
Output 1
Output 2
When i change to X_AXIS it is coming everything in one line and when i switch to Y_AXIS then it is coming new line means vertically.
But my requirement is all the checkbox should come next line means after JLabel.
JLabel should come in line and all the checkBox should come in one line.
public class CheckBoxWithJLabel {
public static void main(String[] args) {
JFrame f= new JFrame("CheckBox Example");
JPanel panel = new JPanel();
panel.setBounds(40,80,600,200);
JCheckBox chk_Embrodary=new JCheckBox("Embrodary");
JCheckBox chk_Cutting=new JCheckBox("Cutting");
JCheckBox cb_Sewing=new JCheckBox("Sewing");
panel.setLayout(new javax.swing.BoxLayout(panel, javax.swing.BoxLayout.X_AXIS));
JLabel lblHeader=new JLabel("Job Work Process Selection");
panel.add(lblHeader);
panel.add(chk_Embrodary);
panel.add(chk_Cutting);
panel.add(cb_Sewing);
f.add(panel);
f.setSize(600,400);
f.setLayout(null);
f.setVisible(true);
}
}
I want this output like
this
How to solve this problem?
I would highly suggest you to have a look through the Java Swing Tutorial, especially the Laying Out Components Within a Container section, since it seems you lack some basic understanding of how Swing and its Layout Managers are supposed to be used.
Regarding your problem:
Currently, you are using a single BoxLayout, which " puts components in a single row or column". You only want that behavior for your JCheckBoxes though, and not for your JLabel. Keeping this in mind, the solution is to split up your components and to not put all of them in a single JPanel. Doing this will grant you more flexibility in how you design your GUI, since you can use multiple layouts in different nested panels.
You could do something like this (explanation in the code comments):
public static void main(String[] args) {
JFrame f = new JFrame("CheckBox Example");
// add a Y_AXIS boxlayout to the JFrames contentpane
f.getContentPane().setLayout(new BoxLayout(f.getContentPane(), BoxLayout.Y_AXIS));
JCheckBox cbEmbrodary = new JCheckBox("Embrodary");
JCheckBox cbCutting = new JCheckBox("Cutting");
JCheckBox cbSewing = new JCheckBox("Sewing");
// no need to set the bounds, since the layoutmanagers will determine the size
JPanel labelPanel = new JPanel(); // default layout for JPanel is the FlowLayout
JLabel lblHeader = new JLabel("Job Work Process Selection");
labelPanel.add(lblHeader); // JPanel for the label done
// JPanel for the comboboxes with BoxLayout
JPanel cbPanel = new JPanel();
cbPanel.setLayout(new BoxLayout(cbPanel, BoxLayout.X_AXIS));
cbPanel.add(cbEmbrodary);
cbPanel.add(cbCutting);
cbPanel.add(cbSewing);
f.add(labelPanel);
f.add(cbPanel);
// No need to set the size of the JFrame, since the layoutmanagers will
// determine the size after pack()
f.pack();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
}
Output:
Sidenotes:
Don't set fixed sizes via setSize() or setBounds() to your components. Swing is designed to be used with appropariate LayoutManagers, and if you do that, calling pack() on the JFrame before setting it visible will layout the components and determine their appropriate size. (Also, don't use null-layout for the same reasons)
If you need the JLabel to not be centered but left aligned, like in your screenshot, then use the following:
FlowLayout layout = (FlowLayout) labelPanel.getLayout();
layout.setAlignment(FlowLayout.LEFT);
I am adding JLabels from an Arraylist to a JPanel and they will only display if i set a layout on the panel but i want to set the location of the labels myself when i try panel = new JPanel(null); all labels are not displayed.
Frame:
public static void Frame(){
panel = new JPanel(null);
JFrame frame = new JFrame("New");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.pack();
frame.setSize(400,400);
frame.add(panel);
}
ArrayList iteration that adds labels to panel
private static void printArray() {
for(int i = 0; i < food.size(); i++){
component = new JLabel(new Food(food.get(i).getColor(),
food.get(i).getIconHeight(), food.get(i).getIconWidth(),
food.get(i).getLocationX(), food.get(i).getLocationY()));
panel.add(component);
component.setLocation(food.get(i).getLocationX(),
food.get(i).getLocationY());
}
}
I can see from Debug it is definitely getting the location information, so why is it not putting it in this location.
The reason to set layout as null is so i can update the position of the label so i can "move" it around with keyboard input
The first thing you need to do is understand what job the layout manager actually does, because if you're going to remove it, you're going to need to take over it's work.
Layout managers are responsible for determining both the size and position of the components. They do this through a variety of means, but can make use of the getPreferred/Minimum/MaximumSize methods of the components.
So this would suggest you need to make your own determinations about these values, for example...
component = new JLabel(new Food(food.get(i).getColor(),
food.get(i).getIconHeight(), food.get(i).getIconWidth(),
food.get(i).getLocationX(), food.get(i).getLocationY()));
component.setSize(component.getPreferredSize());
component.setLocation(food.get(i).getLocationX(), food.get(i).getLocationY());
I'd also recommend using the Key Bindings over KeyListener, it doesn't suffer from the same focus related issues
I'm trying to have painted into a JPanel (which is inside a ScrollPane), a bunch of labels and RadioButtons, dynamically. I receive an ArrayList with "Advice" objects, and I want to iterate over them to represent them in a way I have a label that describes them, and then, two radio buttons (to choose "Yes" or "No").
But at the moment, with this code at the JFrame's constructor, it's not properly working:
// My constructor
public CoachingFrame(AdvicesManager am) {
initComponents();
this.am = am;
// I set the layout for the inner panel (since ScrollPane doesn't allow BoxLayout)
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
// Iterate over the arraylist
for(int i=0;i<am.advices.size();i++){
//Add elements to the panel
panel.add(new JLabel( am.advices.get(i).getQuestion()));
ButtonGroup group = new ButtonGroup();
// Group the RadioButtons inside another panel, so I can use FlowLayout
JPanel buttonsPanel = new JPanel();
buttonsPanel.setLayout(new FlowLayout());
JRadioButton rad1 = new JRadioButton();
JRadioButton rad2 = new JRadioButton();
group.add(rad1);
group.add(rad2);
buttonsPanel.add(rad1);
buttonsPanel.add(rad2);
// Add the radiobuttons' panel to the main one, and revalidate
panel.add(buttonsPanel);
panel.revalidate();
}
// Finally, add the panel to the ScrollPane.
questions.add(panel);
}
I receive the arraylist correctly; I already checked that. The problem seems to be when painting the components.
Since I always use the NetBeans GUI creator, I'm not very used to add components via code. Can someone help me? I guess I'm missing something here.
edit: Note that "questions" is the ScrollPane object!
edit 2: This "questions" panel should have all those components painted: http://i.imgur.com/tXxROfn.png
As Kiheru said, ScrollPane doesn't allow views (like my JPanel) to be added with .add(), instead, I had to use .setViewportView(Component). Now it's working perfectly, thank you!
i'm building a Java program. The core of this program is visualized in a JFrame with a JMenuBar and various JMenuItem and JMenu. The point is that I added a centralPanel to all the frame,but if I add something to the centralPanel it shows only if i resize the main frame, reducing it or enlarging it!
Here's the code:
This is the constructor:
public UserFrame(Sistema system)
{
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
this.setSize(screenSize.width, screenSize.height);
storicoPanel = new JPanel();
carrelloPanel = new JPanel();
carrelloFrame = new JFrame();
pane = new JScrollPane(storicoArea);
close = new JButton("Chiudi");
this.sistema = system;
menu = new JMenuBar();
this.setJMenuBar(menu);
centralPanel = new JPanel();
add(centralPanel);
Here i added the centralPanel, and here, in an ActionListener, i try to add something to it, but it doesnt' work:
public ActionListener createVisualizzaStorico(final ArrayList<Acquisto> array)
{
class Visualize implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
storicoPanel.removeAll();
for(Acquisto a : array)
{
Articolo temp = a.getArticolo();
if(temp instanceof Vacanza)
storicoPanel.add(new VacanzaPanel((Vacanza)temp));
else if(temp instanceof BeneDiConsumo)
storicoPanel.add(new BeneDiConsumoPanel((BeneDiConsumo)temp));
else if(temp instanceof Cena)
storicoPanel.add(new CenaPanel((Cena)temp));
else
storicoPanel.add(new PrestazioniOperaPanel((PrestazioneOpera)temp));
}
centralPanel.add(storicoPanel);
centralPanel.repaint();
Could you please help me? Thanks!
Use a CardLayout instead of trying to add and remove component/panels. It's much cleaner and you don't have to worry about the things that may go wrong, like what you're facing here.
See this example to see how easy and cleaner it is. Also see How to Use CardLayout tutorial
Side Notes
A component can only have one parent container. Though I don't think this is causing a problem for you. It's good to know. First I see you trying to add storicoPanel to a JScrollPane, JScrollPane that you never add to the centerPanel. Then you later add the storicoPanel to the centerPanel. The JScrollPane will no longer be the parent after this.
I'm not sure what you're using this carrelloFrame = new JFrame(); for, but you're class is already a JFrame, why create another?
Just FYI, when adding components dynamically, you need to revalidate() and repaint(). Though, in your situation, I am totally against the adding and removing of components, because this looks like a perfect case for a CardLayout.
Try these..
centralPanel.updateUI(); // or
SwingUtilities.updateComponentTreeUI(getRootPane());
Execute your frame code in SwingUtilities.invokeLater()
Instead of repaint() call updateUI() or
SwingUtilities.updateComponentTreeUI(getRootPane()) to update the
user interface.
I have a JScrollPane on a panel (which has many panels inside of it) and when I open the frame with the scroll pane on it, the fame is scrolled to the bottom. Is there anyway I can avoid this?
Here are some facts:
The panel the scroller is on contains multiple panels. Some of these panels have text fields. I have tried to set the carat of the text fields to 0 and this did not work.
I know there should be actual code, but when I tried to make a mock pane (as the one I am using is intertwined with a lot of code) it is not replicating the issue.
The panel that is being scrolled is being generated using a loop that generates a series of questions... so a text box, a said amount of buttons/answers, and a text box and label that shows the amount of points for each question.
The last elements of my panel that is being scrolled are a JTextArea and a JLabel.
Below is the code to declare those.
Is there anyone out there that could at least throw out an idea of what would be making the scroll pane automatically go to the bottom?
Here is the declaration of the pane and the panels inside/outside of it
JPanel newPanel = new JPanel(new BorderLayout(0, 0));
JPanel showPanel = new JPanel();
BoxLayout layout = new BoxLayout(showQuizPanel, BoxLayout.Y_AXIS);
showQuizPanel.setLayout(layout);
buttonPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));
buttonPanel.setBackground(Color.white);
newPanel.setBackground(Color.white);
showPanel.setBackground(Color.white);
populateButtonPanel();
populateShowPanel(showPanel, buttonPanel);
populateQuestions(showPanel);
JScrollPane scrollPane = new JScrollPane(showPanel, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
scrollPane.getViewport().setBackground(Color.WHITE);
scrollPane.setAlignmentX(JScrollPane.CENTER_ALIGNMENT);
scrollPane.getVerticalScrollBar().setUnitIncrement(16);
scrollPane.getVerticalScrollBar().setValue(0);
scrollPane.getViewport().setViewPosition(new Point(0,0));
newPanel.add(scrollPane, BorderLayout.CENTER);
return newPanel;
code to declare last elements on page
JPanel pPanel = new JPanel(new FlowLayout(FlowLayout.CENTER));
pPanel.setBackground(Color.WHITE);
pPanel.add(qValue);
pPanel.add(new JLabel("Points"));
qArea.add(pPanel);
qArea.add(Box.createVerticalStrut(50));
qValue.setCaretPosition(0);
Thanks!
I believe that when you add text to a text area when building the GUI, the scroll pane will scroll to make the text area visible.
So basically you need to reset the scroll pane to the top.
You can use code like the following after adding all components to the scroll pane:
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
scrollPane.getViewport().setViewPosition( new Point(0, 0) );
}
});
The invokeLater() adds the code to the end of the Event Dispatch Thread (EDT) so that it gets executed after the GUI is visible.
Of course this code assumes that you are creating the rest of the GUI properly on the EDT.