I have two classes, one AnalogClock class and one MainInterface class.
I've created a timeChanged method in the AnalogClock class and it gets called whenever the time has changed. My AnalogClock is basically a JPanel with a drawing. In MainInterface I setup a JFrame and add an Object of my AnalogClock.
Is it possible to change the Title of my Window whenever 'timeChanged' is called? I tried to use getParent() or getRootParent() but they don't recognise setTitle().
Use getWindowAncestor method from SwingUtilities.
//This gives you the first Window Object that contains the panel component
Window window = SwingUtilities.getWindowAncestor(panel);
//Cast it to JFrame
JFrame frame = (JFrame) window;
//Now, change the title
frame.setTitle("New Title");
The simplest way would be to pass a reference of the JFrame to the JPanel and invoking setTitle(). Using getParent(), you will have identify the proper type of the returned Container and then once you've found your JFrame reference, cast to it and call setTitle.
I usually do it according to the first suggestion.
It sounds like timeChanged should be in your MainInterface class because timeChanged needs to reference both the AnalogClock and the JFrame. The reason is that your AnalogClock probably should not be coupled to your JFrame.
Related
I've searched and could not find the answer I need to do the following: I have two java files: one JFrame, one JPanel. I configured a button in the JFrame to open up the JPanel from within the main frame with a new size of 800,800. Now, I want to close the JPanel and go back to the original JFrame (the one that originally was at size 500,500 with an image). It seems simply straightforward, but I've created an instance of the main frame from within the JPanel and set the jPanel to (this.setVisible(false)). I created a new jFrame object and set its visibility to true. What happens is, a new instance of the JFrame appears alright, but the JFrame at 800,800 with no image still appears as well. I've tried several configurations of getContentPane(), setContentPane() and even tried passing a JFrame parameter to the constructor of the JPanel. I'm not sure where I am going wrong with this, but any help would be much appreciated. All I want is the original JFrame with the original size and image displayed. Thank you in advance.
private void jButton_closeActionPerformed(java.awt.event.ActionEvent evt) {
this.setVisible(false);
mainMenuFrame = new MainMenuFrame();
mainMenuFrame.setVisible(true);
invalidate(); validate();
repaint();
}
you could open and close the jpanel from within your JFrame. the button would be also added to the jframe instead of the jpanel. for easier accessing use the jpanel as member variable
Okay currently I am trying to make a multi-window program.
And from seeing other forums, it seems for you to do that in Java JFrame you must update its content pane by adding the new JComponent(new window/layout/idk), set the current window visibility to false, set the new one visibility to true and validate &/ repaint content pane:
contentPane.add(newWindowPanel);
currentWindowPanel.setVisible(false);
newWindowPanel.setVisible(true);
contentPane.validate();
contentPane.repaint();
now, what I am trying to do and partially have done is created a class that extends JPanel, and this class stands to be the top of an hierarchy for many other JPanel classes that I am going to create.
Within that class I have this method :
public void updateContentPane(Container contentPane, JPanel currentPanel, JPanel nextPanel){
contentPane.add(nextPanel);
currentPanel.setVisible(false);
nextPanel.setVisible(true);
contentPane.validate();
contentPane.repaint();
}
When I call this method within one of the child classes, it doesn't work.
updateContentPane(WindowMain.contentPane, this, mainMenuClass);
Each of the child class inherits the JPanel characteristic.
"WindowMain" is a class that extends JFrame, and "contentPane" is a static container variable that holds the frame contentPane.
"this" represents the current class (inherits JPane), but "this" don't actually work new Object() works.
"mainMenuClass" also inherits JPanel and has already been instantiated in this class.
My goal is to simply jump from one scene to the other by calling that method. But it goes through the code (debug) but nothing happens. But, if I take the code within the method and place it inside a button listener it works fine.
(Sorry for all this writing, it will probably bring some confusion at that, but I need to figure this out nonetheless, and I will set condition for when the contentPane already contains a class, so no need to mention it)
You could just update the whole frame by doing
frame.revalidate();
frame.repaint();
I have Main class, StartFrame extends JFrame, and UserPanel extends JPanel which I add to StartFrame. I have button in the UserPanel, how can I close StartFrame when I press the button(I am familiar with event handling it's not a problem the issue is how to sent info to the StartFrame) . Or it is better to just change the panel of the frame(size if need) and reuse it?
If you want to close a window that is enclosing a component, you need a reference to that Window, and SwingUtilities has a method that can help you get this: getWindowAncestor(Component c). Then you could call dispose() on the window returned.
i.e.,
Window win = SwingUtilities.getWindowAncestor(myJPanel);
win.dispose();
Note that this is fine if you're using this to end your GUI, but if your goal is to swap views, then a better suggestion is not to swap Windows, but rather to leave the main JFrame visible but to instead swap components it shows with a CardLayout.
The button is already on the frame (on the upper right, here). Just call JFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE) when constructing it and it will work as the user expects.
Other tip
Don't extend frame or panel, but instead just create and use them.
I am switching on button click to new JPanel with the use of:
JPanel newP = new ProjectPage();
contentPane.revalidate();
setContentPane(newP);
Where ProjectPage is:
public class ProjectPage extends JPanel
But how I create button in my new ProjectPage class that will take me back to my original panel?
My main screen class declared like so:
public class MainScreen extends JFrame
Use a CardLayout, as shown here.
See How to Use CardLayout for details.
As more general advice, do not extend JPanel or JFrame, but simply keep references to them & build them as needed for each use. Part of this problem seems to be scope - the relevant panels are not 'visible' to the calling code. Keeping references to them in the main class is an easy solution to that.
If you want to go back to the original JPanel, you have to keep a reference of it somewhere in your class by adding a field private JPanel oldPanel;
When you create your new panel, get the old Panel and save it in that field like:
oldPanel = getContentPane();
JPanel newP = new ProjectPage();
contentPane.revalidate();
setContentPane(newP);
and when you want to go back to your original panel, you do:
setContentPane(oldPanel);
I want one JFrame to have a method like this:
private void someEvent(java.awt.event.ActionEvent evt){
//initialize another JFrame
//set the new JFrame to be visible
//set this JFrame to be disabled
}
Which is possible, but I also want the main JFrame to perform something when the newly created JFrame is disposed. I don't want to pass in the main JFrame to the new JFrame however. Is this possible?
Instead, use CardLayout to switch between the two desired content panes. There's an example here.
Don't have one JFrame create and display another JFrame. Instead the second window should be a JDialog, either modal if you want the first window frozen until the second has been dealt with or non-modal if otherwise. If modal then the first window's code will resume once the JDialog has been disposed of, and the code flow will start right after the setVisible(true) call on the dialog. If non-Modal, you'll likely want to add a WindowListener to the dialog.
For example, please check out my code here, here, and here.