I was trying out JLayeredPane. So, in the following code, I created a JLayeredPane and a JLabel. I added the label to the layered pane, which I added to a JPanel. This panel was then added to a JFrame.
public static void main(String[] args) {
frame = new JFrame("LayeredPane Example");
frame.setPreferredSize(new Dimension(500,500));
layeredPane = new JLayeredPane();
layeredPane.setPreferredSize(new Dimension(400, 400));
JLabel label = new JLabel("Label on LayeredPane");
label.setLocation(200, 200);
System.out.println("Width " + label.getWidth() );
label.setBounds(20, 20, 400, 40);
layeredPane.add(label);
layeredPane.setLayer(label, 10, 1);
frame.setLayout(new BorderLayout());
JPanel panel = new JPanel();
panel.add(layeredPane);
frame.add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
Now the problem is that if I do not have the statement label.setBounds(20, 20, 400, 40);, then the label does not appear on the layered pane. This raises two questions:
Why is setBounds so important?
Probably a part of my previous questions answer, the label had an initial height and width of 0 before setting bounds, which might be the reason setBounds is important. In that case, I want to know how can I determine appropriate bounds for a Swing component when I am adding it to a JLayeredPane. (If my bounds are less than the appropriate size of the component, the component will appear hidden)
Edit:
The first question was answered earlier in more detail here.
Regarding:
Why is setBounds so important: A JLayeredPane uses essentially a null layout, and whenever you use null layouts, you the coder are completely responsible for both the size and position of the components that you add. That's simply the rules of this layout.
How to determine the appropriate bounds: One thing I've done is simply to let the component tell me what its preferredSize is and then use it for its size:
myJLabel.setSize(myJLabel.getPreferredSize());
Another thing I've done is to use non-opaque JPanels for each layer of my JLayeredPane, give these JPanels appropriate layouts and then add my components to the appropriate layer JPanel. I then use a listener to be sure that the layer JPanel's size matches that of its JLayeredPane container.
Related
Somehow I don't the scrollpane to show up. What do I need to change?
bigP = new JLabel();
setLayout(new BorderLayout());
JPanel helper = new JPanel(new FlowLayout());
helper.add(bigP);
helper.setPreferredSize(new Dimension(500,600));
helper.add(new JScrollPane(bigP, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS));
picPane = new JPanel(new BorderLayout());
picPane.add(helper,BorderLayout.CENTER);
picPane.setMaximumSize(new Dimension(500, 600));
picPane.setVisible(true);
add(picPane, BorderLayout.CENTER);
After an image is chosen this line is called:
bigP.setIcon(img);
I figured out that I most certainly will need the helper-panel as the BorderLayout would only take one component (as far as I understood).
Unfortunately my scrollpane won't show up at all though the picture does.
helper.setPreferredSize(new Dimension(500,600));
Don't hardcode a preferred size. The panel will determine its own preferred size based on the components added to the panel.
JPanel helper = new JPanel(new FlowLayout());
helper.add(bigP);
sc = new JScrollPane(bigP,JScrollPane
Also a component can only have a single parent. In the above code you attempt to add "bigP" to "helper". But then in the next statement you add it to the scrollpane, so "bigP" is removed from the "helper" panel and will only appear in the scrollpane.
//pic.add(bigP,BorderLayout.CENTER);
pic.add(helper,BorderLayout.CENTER);
Also you never add the scroll pane to the "pic" panel. The code should be:
//pic.add(bigP,BorderLayout.CENTER);
//pic.add(helper,BorderLayout.CENTER);
pic.add(sc, BorderLayout.CENTER);
So now you should have a structure that looks like:
- pic
- sc
- bigP
It would also help if you use more descriptive names so everybody knows what those variable are.
I would like to achieve the below layout.
There are 6 panels. The 4 buttons at the top are one panel, and the 3 buttons at the right side of the image are also in one panel. Apart from those two there are 4 other panels as indicated by the borders. I tried the below code but displays everything in a scattered way.
mainPanel.add(topToolBarPanel,BorderLayout.PAGE_START);
mainPanel.add(lefsideToolBarPanel,BorderLayout.LINE_START);
mainPanel.add(descriptionPanel,BorderLayout.LEFT);
mainPanel.add(mapPanel,BorderLayout.CENTER);
mainPanel.add(propertiesPanel,BorderLayout.EAST);
mainPanel.add(tablePanel,BorderLayout.PAGE_END);
How can I achieve the design as shown in the image? I need all the panels to be arranged inside that mainPanel. I cannot use null layout though. Please advice.
After trashgod's answer :
JPanel gridPanel = new JPanel(new GridLayout(1, 0));
gridPanel.add(jInternalFrame1);
gridPanel.add(descriptionPanel);
mainPanel.add(gridPanel, BorderLayout.LINE_START);
mainPanel.add(topToolBarPanel,BorderLayout.PAGE_START);
mainPanel.add(tablePanel,BorderLayout.PAGE_END);
mainPanel.add(mapPanel,BorderLayout.CENTER);
mainPanel.add(PropertiesPanel,BorderLayout.LINE_END);
What I get :
Add lefsideToolBarPanel and descriptionPanel to a panel having GridLayout; add the new panel to the BorderLayout.
Panel p new Panel(new GridLayout(1, 0));
p.add(lefsideToolBarPanel);
p.add(descriptionPanel);
//mainPanel.add(lefsideToolBarPanel, BorderLayout.LINE_START);
//mainPanel.add(descriptionPanel, BorderLayout.LEFT);
mainPanel.add(p, BorderLayout.LINE_START);
There is no BorderLayout.LEFT. See also A Visual Guide to Layout Managers.
Addendum: Your updated question shows elements of topToolBarPanel, which should be added to PAGE_START, rather than LINE_START.
//mainPanel.add(topToolBarPanel,BorderLayout.LINE_START);
mainPanel.add(topToolBarPanel,BorderLayout. PAGE_START);
The width of the propertiesPanel and height of the tablePanel need to be increased. I used setSize()…
For the propertiesPanel, you can override getPreferredSize(), as discussed here. For the tablePanel, override getPreferredScrollableViewportSize() to customize the size of the table's enclosing JScrollPane, for example.
I suggest using a JLabel as your "layout" to use exact positioning of yout objects with setBounds(x, y, width, height). It would look similar to this :
JButton button = new JButton("Text or Image");
JLabel backgr = new JLabel();
JFrame frame = new JFrame("JLabel as Layout");
button.setBounds(100, 200, 340, 40);
backgr.add(button);
frame.add(backgr);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(600, 600);
frame.setLocation(40, 40);
frame.validate();
frame.setVisible(true);
I know that this is just a quick example for you, but I think it should do for explanation... so just add everything on the backgr JLabeland your good to go. Quick and dirty example but the a way to go.
I have multiple JTextAreas inside a JPanel. I am using a BoxLayout to make them align vertically and fill the width of the container.
It works, but they seem to expand to fill the entire height as well.
What I really want is simple - a text area that wraps text where I can control the width but allow the height to scale dynamically as more lines are added. The above method was just my best attempt at it. If there is a solution that uses a different layout manager, different text component, etc, that works.
minimal verifiable example below:
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setPreferredSize(new Dimension(300, 300));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel textAreas = new JPanel();
textAreas.setLayout(new BoxLayout(textAreas, BoxLayout.Y_AXIS));
JTextArea area1 = new JTextArea();
area1.append("this is a string");
area1.setLineWrap(true);
area1.setWrapStyleWord(true);
textAreas.add(area1);
JTextArea area2 = new JTextArea("and another that is much longer, so that it wraps to the next line");
area2.setLineWrap(true);
area2.setWrapStyleWord(true);
textAreas.add(area2);
JScrollPane scrollPane = new JScrollPane();
scrollPane.setViewportView(textAreas);
frame.add(scrollPane);
frame.pack();
frame.setVisible(true);
}
I have done research on this topic on my own, including looking at different layout managers (http://docs.oracle.com/javase/tutorial/uiswing/layout/visual.html), and checking other questions on the site, but I haven't had much luck.
TLDR: Can I make it so each element of a layout has a height that scales to its content but a fixed width? If so how?
What I really want is simple - a text area that wraps text where I can control the width but allow the height to scale dynamically as more lines are added.
The BoxLayout respects the maximum size so the text area grows to fill all the space available in the panel. You can override the getMaximumSize() method to return the preferred height by using something like:
JTextArea area1 = new JTextArea()
{
public Dimension getMaximumSize()
{
Dimension d = super.getMaximumSize();
d.height = getPreferredSize().height;
return d;
}
};
It works...
Not really. Make the frame wider and the text will unwrap. Then shrink the frame and the scrollbar will appear. That is the text will not wrap again
What you need to do is force the panel added to the scroll pane to be the same width as the viewport. This will allow wrapping to work properly.
You do this by implementing the Scrollable interface on the panel. Specifically you need to override the getScrollableTracksViewportWidth() method to return true.
Or an easier solution is to use the Scrollable Panel class which allows you to set properties of the panel to control this behaviour.
You can replace a JPanel with the ScrollablePanel:
//JPanel textAreas = new JPanel();
ScrollablePanel textAreas = new ScrollablePanel();
textAreas.setScrollableWidth( ScrollablePanel.ScrollableSizeHint.FIT );
Edit:
If there is a solution that uses a different layout manager
Without overriding the getMaximumSize() method of the text areas and when using the Scrollable Panel you should be able to use the following layout managers.
The GridBagLayout allows you to specify the "weightx" constraint. This will allow the component to fill all the available space in the panel.
Or if you don't like specifying all the constrains of the GridBagLayout you could use the Relative Layout which support vertical/horizontal layout of components at their preferred size.
You would just need to use the following to force the component to fill the horizontal space:
//textAreas.setLayout(new BoxLayout(textAreas, BoxLayout.Y_AXIS));
RelativeLayout rl = new RelativeLayout(RelativeLayout.Y_AXIS);
rl.setFill( true );
textAreas.setLayout(rl);
This is the code for my GUI:
public TLGUI(){
final int x=500,y=600;
JFrame frame=new JFrame();
frame.setSize(x, y);
frame.setVisible(true);
frame.setResizable(false);
JLabel labelTL=new JLabel("This is a test label");
JScrollPane pane = new JScrollPane(labelTL,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
JPanel panel=new JPanel();
panel.add(labelTL);
frame.add(panel);
frame.add(pane);
}
I have a huge problem right now regarding the line marked with the ** **.
This code does indeed add a scrollbar to my window, but the problem is that if I place it in front of the TLFrame.add(panel), I wont see it at all (I guess the panel is covering it in this order), and as soon as I turn it around, I can see a scrollbar but the whole frame other than the scrollbar is grey (I suppose the scrollbar is covering the panels contents here).
However, I want both of them to be visible at once, of course. Because my Label is bigger than the Frame, I want to be able to scroll down at least.
I have been working on a small project that is supposed to simulate a gambling game. Unfortunately, I ran into some odd issues while working with BoxLayout. To the best of my knowledge, LayoutManagers usually honor any component's preferred size. However, in the below code, BoxLayout does not.
Here is my code thus far:
import java.awt.*;
import javax.swing.*;
public class Main
{
public static void main(String[] args)
{
JFrame.setDefaultLookAndFeelDecorated(true);
JFrame frame = new JFrame("Suit-Up");
frame.setContentPane(makeGUI());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(900,450);
frame.setLocationRelativeTo(null);
frame.setResizable(false);
frame.setVisible(true);
}
public static JPanel makeGUI()
{
JPanel main = new JPanel();
main.setMinimumSize(new Dimension(900,450));
main.setBackground(Color.red);
JPanel infoPanel = new JPanel();
infoPanel.setLayout(new BoxLayout(infoPanel, BoxLayout.LINE_AXIS));
infoPanel.setPreferredSize(new Dimension(900,60));
infoPanel.setBackground(Color.green);
main.add(infoPanel);
JPanel infoText = new JPanel();
infoText.setLayout(new BoxLayout(infoText, BoxLayout.PAGE_AXIS));
infoPanel.add(infoText);
JPanel moneyText = new JPanel();
moneyText.setLayout(new BoxLayout(moneyText, BoxLayout.LINE_AXIS));
infoText.add(moneyText);
JPanel lastGameText = new JPanel();
lastGameText.setLayout(new BoxLayout(lastGameText, BoxLayout.LINE_AXIS));
infoText.add(lastGameText);
JButton playAgain = new JButton("Play Again ($20)");
playAgain.setPreferredSize(new Dimension(200,60));
infoPanel.add(playAgain);
JButton finish = new JButton("End Session");
finish.setPreferredSize(new Dimension(200,60));
infoPanel.add(finish);
JPanel cardPanel = new JPanel();
cardPanel.setLayout(new BoxLayout(cardPanel, BoxLayout.LINE_AXIS));
main.add(cardPanel);
return main;
}
}
Despite specifying preferred sizes for both JButtons, they do not change their sizes. I have tried setMaximumSize() and setMinimumSize() as well, but neither had any effect.
Am I overlooking something obvious, or is this a limitation of BoxLayout?
"To the best of my knowledge, LayoutManagers usually honor any component's preferred size" - That's actually not true. preferred/min/max size are just "hints" that layout managers MAY use to determine how best to layout there contents. Layout managers are allowed to simply ignore them if they want to.
From the JavaDocs
BoxLayout attempts to arrange components at their preferred widths
(for horizontal layout) or heights (for vertical layout). For a
horizontal layout, if not all the components are the same height,
BoxLayout attempts to make all the components as high as the highest
component. If that's not possible for a particular component, then
BoxLayout aligns that component vertically, according to the
component's Y alignment. By default, a component has a Y alignment of
0.5, which means that the vertical center of the component should have the same Y coordinate as the vertical centers of other components with
0.5 Y alignment.
Similarly, for a vertical layout, BoxLayout attempts to make all
components in the column as wide as the widest component. If that
fails, it aligns them horizontally according to their X alignments.
For PAGE_AXIS layout, horizontal alignment is done based on the
leading edge of the component. In other words, an X alignment value of
0.0 means the left edge of a component if the container's ComponentOrientation is left to right and it means the right edge of
the component otherwise.