I am confused about how JFrame extends the JButton vertically to match JFrame min size but not horizontally. I would like for it to not extend in either direction and know why it extends or doesn't.
import javax.swing.*;
import java.awt.*;
public class somestring {
public static void main(String []args){
JFrame frame = new JFrame();
Container content = frame.getContentPane();
content.setLayout(new BorderLayout());
Toolkit toolkit = Toolkit.getDefaultToolkit();
Dimension max = toolkit.getScreenSize();
frame.setMinimumSize(new Dimension(1000,1000));
frame.setSize(max);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton s = new JButton("generate somestring");
s.setPreferredSize(new Dimension(400,400));
content.add(s, BorderLayout.WEST);
frame.pack();
frame.setResizable(false);
frame.setVisible(true);
}
}
I am confused about how JFrame extends the JButton vertically to match JFrame min size but not horizontally.
content.setLayout(new BorderLayout());
...
content.add(s, BorderLayout.WEST);
The default layout manager of the content pane of the frame is the BorderLayout, so the above is unnecessary.
In any case, the reason it extend vertically is because that is the rule of the BorderLayout when you add a component to the WEST.
Read the section from the Swing tutorial on Layout Managers. The section on the BorderLayout will explain the rules for adding components to the WEST.
I would like for it to not extend in either direction
Then you need to use a different layout manager.
For example you could use a FlowLayout. The button will be centered at the top of the frame.
Or you could use a GridBagLayout (with the default GridBagConstraints). The button will be centered both horizontally and vertically.
frame.pack();
frame.setResizable(false);
You should set the resizable property BEFORE invoking pack().
frame.setMinimumSize(new Dimension(1000,1000));
frame.setSize(max);
Not sure why you are setting the minimum size and invoking setSize(). If you want the button to be displayed at its preferred size, then just invoke pack().
Related
I am trying to make a GUI for a game. I am very new to Java, especially GUI. The code below is a snippet which is supposed to make a JFrame with nested panels for organization. It works until I add buttons to the button panel. They end up on the boardBckg panel. If I manage to place them on the correct panel the JTextField disappears or it takes up the entire screen. I have been working on this part of the code for the past two days and I could really use GUI tips.
private void makeWindow()
{
boardPanel = new JPanel();
boardBckg = new JPanel();
menuPanel = new JPanel();
save = new JButton("Save");
save.setSize(Buttons);
load = new JButton("Load");
load.setSize(Buttons);
replay = new JButton ("Replay");
replay.setSize(Buttons);
words = new JTextField();
frame = new JFrame(title);
boardPanel.setSize(PANEL);
boardPanel.setMaximumSize(MAX);
boardPanel.setMinimumSize(MIN);
boardPanel.setLayout(new GridLayout(m,n));
boardBckg.setSize(1000, 1000);
boardBckg.setBackground(Color.cyan);
boardBckg.add(boardPanel, BorderLayout.CENTER);
frame.setSize(1500, 1000);
frame.setResizable(false);
frame.setVisible(true);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
BoxLayout vertical = new BoxLayout(menuPanel, BoxLayout.Y_AXIS);
menuPanel.setSize(500, 1000);
menuPanel.setBackground(Color.blue);
menuPanel.setLayout(vertical);
frame.add(boardBckg);
frame.add(menuPanel);
JPanel iGiveUp = new JPanel();
iGiveUp.setBackground(Color.black);
JPanel buttons = new JPanel();
buttons.setBackground(Color.darkGray);
buttons.add(save);
buttons.add(load);
buttons.add(replay);
menuPanel.add(iGiveUp);
menuPanel.add(buttons);
iGiveUp.add(words);
boardBckg.add(boardPanel, BorderLayout.CENTER);
The default layout of a JPanel is the FlowLayout. You can't just specify a BorderLayout constraint when you add the component to the panel.
frame.add(boardBckg);
frame.add(menuPanel);
The default layout for (the content pane of) the frame is a BorderLayout. If you don't specify a constraint, then the component is added to the BorderLayout.CENTER. Problem is only one component can be added to the CENTER so you only see the last comoponent added.
frame.setVisible(true);
Component should be added to the frame BEFORE the frame is packed and made visible. So the above statement should be the last statement in your constructor.
I have no ideas what your desired layout is but you need to start with something simple and take advantage of the default BorderLayout of the frame.
So your basic logic might be something like:
JPanel menuPanel = new JPanel()
menuPanel.setLayout(new BoxLayout(menuPanel, BoxLayout.Y_AXIS));
menuPanel.add(...);
menuPanel.add(...);
JPanel center = new JPanel();
center.setLayout(...);
center.setBackground( Color.BLUE );
center.add(...);
frame.add(menuPanel, BorderLayout.LINE_START);
frame.add(center, BorderLayout.CENTER);
frame.pack();
frame.setVisible( true );
The main point is to break the panels down logically and add them to the frame one at a time. So first get the menu and its child components added to the frame is the correct position. Then you can add the CENTER panel and its child components.
I'm in the process of creating a circuit editor (similar to any regular paint software with a basic menu and a canvas with specifiable dimensions). I am currently trying to transform the previously unscrollable canvas (JPanel) to a scrollable one.
The obvious design error at the moment is that while the scrollbars seem to correctly reflect the internal size of the canvas (which can of course be way bigger than the JFrame), due to the canvas JPanel being added in the CENTER of the BorderLayout of the master panel, it always resizes along with the JFrame.
public final class MainFrame extends JFrame
{
public MainFrame()
{
JPanel menuPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
// Populate Menu Panel
// ...
JPanel canvasPanel = new JPanel();
canvasPanel.setBackground(Color.white);
Dimension canvasDims = new Dimension(800,600);
canvasPanel.setPreferredSize(canvasDims);
canvasPanel.setMinimumSize(canvasDims);
canvasPanel.setMaximumSize(canvasDims);
JScrollPane canvasScrollPane = new JScrollPane(
canvasPanel,
JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
JPanel masterPanel = new JPanel(new BorderLayout());
masterPanel.add(menuPanel, BorderLayout.NORTH);
masterPanel.add(canvasScrollPane, BorderLayout.CENTER);
setContentPane(masterPanel);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(1200, 700);
setMinimumSize(new Dimension(500, 500));
setLocationRelativeTo(null);
setVisible(true);
}
I've read quite a few posts regarding centering JPanels and scrollbars but with both complexities added together, things might be a bit more complicated as I haven't yet found a solution.
What I'm really trying to achieve is to have the canvas' JPanel fixed in whatever size the user might have specified and centered in the middle as well as the scrollbars behaving as one would expect like in the beloved windows' paint:
How would you go about doing this/fixing my design? Any help would be greatly appreciated!
P.S. Happy new Year :)
JPanel fixed in whatever size the user might have specified and centered in the middle as well as the scrollbars behaving as one would expect
So you need to nest panels so the canvas panel can be displayed at its preferred size, while the parent panel resizes with the size of the frame.
An easy way to do this is with a JPanel that uses a GridBagLayout. Then you add the canvas panel to this panel using the default GridBagConstraints.
So the basic structure of the panels would be:
JPanel canvas = new JPanel();
canvas.setPreferredSize( new Dimension(300, 300) );
canvas.setBackground(Color.RED);
JPanel wrapper = new JPanel( new GridBagLayout() );
wrapper.add(canvas, new GridBagConstraints() );
frame.add(new JScrollPane(wrapper));
Note: there is no need for your "masterPanel". The default layout manager for the content pane of a JFrame is a BorderLayout, so you just add the "menuPanel" and "scrollPane" directly to the frame with the proper BorderLayout constraints.
I am trying to put a JPanel in the center of a fullscreen JFrame with a defined size, but it's always stretching for the whole screen...
I tried setBounds, setPreferredSize, but they don't work.
This is the code:
public static void showScene(){
//Create the frame to main application.
JFrame frame = new JFrame("Application"); // set the title of the frame
frame.setExtendedState(JFrame.MAXIMIZED_BOTH); // set the size, maximum size.
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create the panel to store the main menu.
JPanel panel = new JPanel();
panel.setPreferredSize(new Dimension(500,200));
panel.setBackground(new java.awt.Color(0,0,255));
frame.add(panel,BorderLayout.CENTER);
}
public static void main (String[] args){
showScene();
}
BorderLayout stretches the contents to fill the parent container.
If you want the child to have smaller size than the parent, use some other LayoutManager (try FlowLayout).
You can change layout using following code.
Container contentPane = frame.getContentPane();
contentPane.setLayout(new FlowLayout(FlowLayout.CENTER, 0,90)));
frame.add(panel);
frame.pack();
For further reference, follow visual guide to layout managers.
Good luck.
public MyLayout (){
frame.setLayout(new BorderLayout());
panel.setLayout(new BorderLayout());
panel.add(new GraphicsSurface(),BorderLayout.CENTER);
frame.add(panel,BorderLayout.NORTH);
frame.add(btn1,BorderLayout.SOUTH);
frame.setSize(500, 500);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
I'm creating a graphic placing it inside a panel
panel.add(new GraphicsSurface(),BorderLayout.CENTER);
and placing this panel inside a JFrame
frame.add(panel,BorderLayout.NORTH);
Except the graphic is displaying outside the JFrame
"I want the Graphic to be displayed centred at the top of the JFrame. I still have more components to ad"
In GraphicsSurface override getPreferredSize and give it the size you want (I guess the size of the clock
class GraphicsSurface extends JPanel {
#Override
public Dimension getPreferredSize() {
return new Dimenstion(..., ...);
}
}
For panel, don't set the layout. The default FlowLayout will work perfectly (it also centers by default -yeeee!). What will happen is that the GraphicsSurface will maintain its preferred size, as FlowLayout will respect it. Then the panel will be stretched to the width of the frame (the height will remain the GraphicsSurface's height), and the GraphicsSurface will be centered in the panel
With this you should be fine, adding the panel to the frame's NORTH. The center will be left for everything else.
You place your panel at frame NORTH.
In north, your panel will take only the widows width. So he has no height (or 1px height).
So try to define a size to your panel:
panel.setPreferedSize(new Dimension(200, 200));
Else, as suggested in comment, place your panel into the CENTER of the frame.
Replace:
frame.add(panel,BorderLayout.NORTH);
by
frame.add(panel,BorderLayout.CENTER);
In center, your panel will get the panel width and height (substract your button height).
Is it possible to have some extra space around the edges of a JFrame that uses AbsoluteLayout? When I have a button as the downwardsmost component on the JFrame, it gets positioned right up against the bottom edge of the JFrame window, and it looks bad. I would like to know if there's a way to add a little extra space between components and the edge of the JFrame while using AbsoluteLayout.
Suggestions:
When you add a component to a JFrame, you're actually adding it to the JFrame's contentPane. To give the contentPane a "buffer" border, consider giving it an EmptyBorder(...) with the parameters being int constants for the amount of border desired around the component.
Avoid using "absolute" layouts for anything, and especially for placing components at easy to place locations for the layout managers, such as at the bottom of the GUI.
For example, note in the GUI created in the code below how the center and bottom JPanel's don't go out to the edge of the GUI because of the empty border:
import java.awt.BorderLayout;
import java.awt.Dimension;
import javax.swing.*;
public class ButtonAtBottom {
private static void createAndShowGui() {
JPanel bottomPanel = new JPanel();
bottomPanel.add(new JButton("Bottom Button"));
bottomPanel.setBorder(BorderFactory.createTitledBorder("Bottom Panel"));
JPanel centerPanel = new JPanel();
centerPanel.setBorder(BorderFactory.createTitledBorder("Center Panel"));
JPanel mainPanel = new JPanel(new BorderLayout());
mainPanel.add(centerPanel, BorderLayout.CENTER);
mainPanel.add(bottomPanel, BorderLayout.PAGE_END);
// **** here I add the border to the mainPanel which I'll
// make into the contentPane
int eb = 25;
mainPanel.setBorder(BorderFactory.createEmptyBorder(eb, eb, eb, eb));
// don't set the preferredSize per Kleopatra, but am doing it
// here simply to make code shorter for this sscce
mainPanel.setPreferredSize(new Dimension(500, 400));
JFrame frame = new JFrame("ButtonAtBottom");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
You can use Box.createRigidArea(dimensions) to create an empty space that you can add below the button.
Set an empty border on your content panel where SIZE is the amount of padding you want.
JFrame frame = new JFrame();
JPanel panel = new JPanel(null);
panel.setBorder(BorderFactory.createEmptyBorder(SIZE,SIZE,SIZE,SIZE);
frame.setContentPane(panel);
//The rest
The arguments are for top, left, bottom and right padding so if you want different paddings on each edge, you can set it accordingly.