I want my panel to fit the frame when I show/hide fields. How could I notify to the parent frame to revalidate?
I thought about pass the frame to my panel's constructor, but I think may have a way this is already done. I remember that there was a protected attribute in JPanel, but there isn't.. maybe i remembering the wrong component.
I need show/hide some fields of my
panel, and I want the panel to fit the
frame.
You mean like a summary/details view and you want the frame size to change? Then try:
SwingUtilities.windowForComponent(...).pack();
you could override the addNotify in the panel into something:
public void addNotify() {
getParent().revalidate();
repaint();
super.addNotify();
}
Not sure if that's what you mean though.
SwingUtilities.getRoot(this).invalidate();
Related
To put it simple, there's a simple java swing app that consists of JFrame with some components in it. One of the components is a JPanel that is meant to be replaced by another JPanel on user action.
So, what's the correct way of doing such a thing? I've tried
panel = new CustomJPanelWithComponentsOnIt();
parentFrameJPanelBelongsTo.pack();
but this won't work. What would you suggest?
Your use case, seems perfect for CardLayout.
In card layout you can add multiple panels in the same place, but then show or hide, one panel at a time.
1) Setting the first Panel:
JFrame frame=new JFrame();
frame.getContentPane().add(new JPanel());
2)Replacing the panel:
frame.getContentPane().removeAll();
frame.getContentPane().add(new JPanel());
Also notice that you must do this in the Event's Thread, to ensure this use the SwingUtilities.invokeLater or the SwingWorker
frame.setContentPane(newContents());
frame.revalidate(); // frame.pack() if you want to resize.
Remember, Java use 'copy reference by value' argument passing. So changing a variable wont change copies of the reference passed to other methods.
Also note JFrame is very confusing in the name of usability. Adding a component or setting a layout (usually) performs the operation on the content pane. Oddly enough, getting the layout really does give you the frame's layout manager.
Hope this piece of code give you an idea of changing jPanels inside a JFrame.
public class PanelTest extends JFrame {
Container contentPane;
public PanelTest() {
super("Changing JPanel inside a JFrame");
contentPane=getContentPane();
}
public void createChangePanel() {
contentPane.removeAll();
JPanel newPanel=new JPanel();
contentPane.add(newPanel);
System.out.println("new panel created");//for debugging purposes
validate();
setVisible(true);
}
}
On the user action:
// you have to do something along the lines of
myJFrame.getContentPane().removeAll()
myJFrame.getContentPane().invalidate()
myJFrame.getContentPane().add(newContentPanel)
myJFrame.getContentPane().revalidate()
Then you can resize your wndow as needed.
Game game = new Game();
getContentPane().removeAll();
setContentPane(game);
getContentPane().revalidate(); //IMPORTANT
getContentPane().repaint(); //IMPORTANT
It all depends on how its going to be used. If you will want to switch back and forth between these two panels then use a CardLayout. If you are only switching from the first to the second once and (and not going back) then I would use telcontars suggestion and just replace it. Though if the JPanel isn't the only thing in your frame I would use
remove(java.awt.Component) instead of removeAll.
If you are somewhere in between these two cases its basically a time-space tradeoff. The CardLayout will save you time but take up more memory by having to keep this whole other panel in memory at all times. But if you just replace the panel when needed and construct it on demand, you don't have to keep that meory around but it takes more time to switch.
Also you can try a JTabbedPane to use tabs instead (its even easier than CardLayout because it handles the showing/hiding automitically)
The other individuals answered the question. I want to suggest you use a JTabbedPane instead of replacing content. As a general rule, it is bad to have visual elements of your application disappear or be replaced by other content. Certainly there are exceptions to every rule, and only you and your user community can decide the best approach.
Problem: My component does not appear after I have added it to the container.
You need to invoke revalidate and repaint after adding a component before it will show up in your container.
Source: http://docs.oracle.com/javase/tutorial/uiswing/layout/problems.html
I was having exactly the same problem!! Increadible!! The solution I found was:
Adding all the components (JPanels) to the container;
Using the setVisible(false) method to all of them;
On user action, setting setVisible(true) to the panel I wanted to
show.
// Hiding all components (JPanels) added to a container (ex: another JPanel)
for (Component component : this.container.getComponents()) {
component.setVisible(false);
}
// Showing only the selected JPanel, the one user wants to see
panel.setVisible(true);
No revalidate(), no validate(), no CardLayout needed.
The layout.replace() answer only exists/works on the GroupLayout Manager.
Other LayoutManagers (CardLayout, BoxLayout etc) do NOT support this feature, but require you to first RemoveLayoutComponent( and then AddLayoutComponent( back again. :-) [Just setting the record straight]
I suggest you to add both panel at frame creation, then change the visible panel by calling setVisible(true/false) on both.
When calling setVisible, the parent will be notified and asked to repaint itself.
class Frame1 extends javax.swing.JFrame {
remove(previouspanel); //or getContentPane().removeAll();
add(newpanel); //or setContentPane(newpanel);
invalidate(); validate(); // or ((JComponent) getContentPane()).revalidate();
repaint(); //DO NOT FORGET REPAINT
}
Sometimes you can do the work without using the revalidation and sometimes without using the repaint.My advise use both.
Just call the method pack() after setting the ContentPane, (java 1.7, maybe older) like this:
JFrame frame = new JFrame();
JPanel panel1 = new JPanel();
JPanel panel2 = new JPanel();
....
frame.setContentPane(panel1);
frame.pack();
...
frame.setContentPane(panel2);
frame.pack();
...
To put it simple, there's a simple java swing app that consists of JFrame with some components in it. One of the components is a JPanel that is meant to be replaced by another JPanel on user action.
So, what's the correct way of doing such a thing? I've tried
panel = new CustomJPanelWithComponentsOnIt();
parentFrameJPanelBelongsTo.pack();
but this won't work. What would you suggest?
Your use case, seems perfect for CardLayout.
In card layout you can add multiple panels in the same place, but then show or hide, one panel at a time.
1) Setting the first Panel:
JFrame frame=new JFrame();
frame.getContentPane().add(new JPanel());
2)Replacing the panel:
frame.getContentPane().removeAll();
frame.getContentPane().add(new JPanel());
Also notice that you must do this in the Event's Thread, to ensure this use the SwingUtilities.invokeLater or the SwingWorker
frame.setContentPane(newContents());
frame.revalidate(); // frame.pack() if you want to resize.
Remember, Java use 'copy reference by value' argument passing. So changing a variable wont change copies of the reference passed to other methods.
Also note JFrame is very confusing in the name of usability. Adding a component or setting a layout (usually) performs the operation on the content pane. Oddly enough, getting the layout really does give you the frame's layout manager.
Hope this piece of code give you an idea of changing jPanels inside a JFrame.
public class PanelTest extends JFrame {
Container contentPane;
public PanelTest() {
super("Changing JPanel inside a JFrame");
contentPane=getContentPane();
}
public void createChangePanel() {
contentPane.removeAll();
JPanel newPanel=new JPanel();
contentPane.add(newPanel);
System.out.println("new panel created");//for debugging purposes
validate();
setVisible(true);
}
}
On the user action:
// you have to do something along the lines of
myJFrame.getContentPane().removeAll()
myJFrame.getContentPane().invalidate()
myJFrame.getContentPane().add(newContentPanel)
myJFrame.getContentPane().revalidate()
Then you can resize your wndow as needed.
Game game = new Game();
getContentPane().removeAll();
setContentPane(game);
getContentPane().revalidate(); //IMPORTANT
getContentPane().repaint(); //IMPORTANT
It all depends on how its going to be used. If you will want to switch back and forth between these two panels then use a CardLayout. If you are only switching from the first to the second once and (and not going back) then I would use telcontars suggestion and just replace it. Though if the JPanel isn't the only thing in your frame I would use
remove(java.awt.Component) instead of removeAll.
If you are somewhere in between these two cases its basically a time-space tradeoff. The CardLayout will save you time but take up more memory by having to keep this whole other panel in memory at all times. But if you just replace the panel when needed and construct it on demand, you don't have to keep that meory around but it takes more time to switch.
Also you can try a JTabbedPane to use tabs instead (its even easier than CardLayout because it handles the showing/hiding automitically)
The other individuals answered the question. I want to suggest you use a JTabbedPane instead of replacing content. As a general rule, it is bad to have visual elements of your application disappear or be replaced by other content. Certainly there are exceptions to every rule, and only you and your user community can decide the best approach.
Problem: My component does not appear after I have added it to the container.
You need to invoke revalidate and repaint after adding a component before it will show up in your container.
Source: http://docs.oracle.com/javase/tutorial/uiswing/layout/problems.html
I was having exactly the same problem!! Increadible!! The solution I found was:
Adding all the components (JPanels) to the container;
Using the setVisible(false) method to all of them;
On user action, setting setVisible(true) to the panel I wanted to
show.
// Hiding all components (JPanels) added to a container (ex: another JPanel)
for (Component component : this.container.getComponents()) {
component.setVisible(false);
}
// Showing only the selected JPanel, the one user wants to see
panel.setVisible(true);
No revalidate(), no validate(), no CardLayout needed.
The layout.replace() answer only exists/works on the GroupLayout Manager.
Other LayoutManagers (CardLayout, BoxLayout etc) do NOT support this feature, but require you to first RemoveLayoutComponent( and then AddLayoutComponent( back again. :-) [Just setting the record straight]
I suggest you to add both panel at frame creation, then change the visible panel by calling setVisible(true/false) on both.
When calling setVisible, the parent will be notified and asked to repaint itself.
class Frame1 extends javax.swing.JFrame {
remove(previouspanel); //or getContentPane().removeAll();
add(newpanel); //or setContentPane(newpanel);
invalidate(); validate(); // or ((JComponent) getContentPane()).revalidate();
repaint(); //DO NOT FORGET REPAINT
}
Sometimes you can do the work without using the revalidation and sometimes without using the repaint.My advise use both.
Just call the method pack() after setting the ContentPane, (java 1.7, maybe older) like this:
JFrame frame = new JFrame();
JPanel panel1 = new JPanel();
JPanel panel2 = new JPanel();
....
frame.setContentPane(panel1);
frame.pack();
...
frame.setContentPane(panel2);
frame.pack();
...
This is probably a very basic question, but I could't find anything about it online.
I'm working in Java swing and have a JPanel with a null Layout Manager (ie using absolute positioning). The JPanel is filling a space in the JFrame so that its size will change when the JFrame is resized. Within this JPanel, I have a number of other components that I have placed using Component.setBounds(). I would like one of these components to be set relative to the bottom of the JPanel, so that when the containing JPanel resizes, the smaller JComponent stays stuck to the bottom of the container.
I have tried to do this by overriding the getLocation() or getBounds() methods to reference the container height, but neither of these seemed to work the way overriding getPreferredSize() would, even after calling revalidate() and repaint(). Unfortunately, using another layout manager like BorderLayout is not an option here.
Is there a way to do something like this? Am I missing something obvious? If not, is there a way to listen for changes in the container's height and re-call .setBounds()?
Try listening to the resize event of the panel:
panel.addComponentListener(new ComponentAdapter() {
#Override
public void componentResized(ComponentEvent arg0) {
component.setBounds(...);
}
});
You can reference panel.getBounds from withing this method and set your components bounds accordingly.
To do this you can add a component listener to your JFrame.
addComponentListener(new ComponentAdapter(){
public void componentResized(ComponentEvent e){
//Do stuff here
}
});
Inside the component listener you can change the sizes and locations of anything you would like to. To stick them to the bottom simply get the size of the JFrame and subtract a specific amount and set that as the y location for what you want stuck to the bottom.
Right now, the background I get is a grey. I want to change it to black. I tried doing something like setBackground(color.BLACK); but it didnt work. Any suggestions?
public test()
{
setTitle("Adjustment Form");
setSize(670,450);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setLayout(new GridLayout(4,6,2,2));
setVisible(true);
}
You could call:
getContentPane().setBackground(Color.black);
Or add a JPanel to the JFrame your using. Then add your components to the JPanel. This will allow you to call
setBackground(Color.black);
on the JPanel to set the background color.
I think what he is trying to say is to use the
getContentPane().setBackground(Color.the_Color_you_want_here)
but if u want to set the color to any other then the JFrame, you use the object.setBackground(Color.the_Color_you_want_here)
Eg:
jPanel.setbackground(Color.BLUE)
setBackground() is the right method to use. Did you repaint after you changed it? If you change it before you make the panel (or its containing frame) visible it should work
I am assuming that we are dealing with a JFrame? The visible portion in the content pane - you have to use jframe.getContentPane().setBackground(...);
How would I force a Frame to repaint() immediately after it is maximized, or resized?
I can't find what method is called when that specific operation takes place. I have a bunch of graphics that are written with Graphic objects in paint and their orientation depends on the real time feedback from getWidth() and getHeight() but paint isn't called when I maximize, only when those pixels change unfortunately.
Register a ComponentListener:
final Component myComponent = makeTheFrameOrWhatever();
myComponent.addComponentListener(new ComponentAdapter() {
#Override
public void componentResized(ComponentEvent e)
{
myComponent.repaint();
}
});
You need to dig further because repaint() and paint() most certainly are called when you resize a frame - it's the only way the frame can cause it's contents to be painted. It is most likely that you're not seeing the repaint reach your specific component in the frame, perhaps because the particular layout you are using is not affected if the window is made larger. Or if you have no layout, then you must subclass Frame and explicitly have it call paint on the subcomponents, since there is no layout manager to do that for you.
Note that whether or not painting is done repeatedly while you are resizing, as opposed to just once after you let go the mouse button may be an operating system option.