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.
Related
I realize it's pointless to include a button that would do the exact same thing as the 'x' in the window, but I've already worked out the placement of my buttons on my GUI and found having the exit button made things much easier if nothing but a placeholder. And I like the practice.
Ok anyways moving on.
I have a parent JFrame (main class actually) that I'd like to keep running open the entire time the program is being run. This isn't my issue. My problem is when opening a child JFrame. I instantiate it in the main class (it's adding a panel component I created) and I just can't figure out how close said JFrame from within the Panel. Is there an easy way of doing so? I already have the WindowConstant set to Dispose on Close.
What I've done so far is created a method getExit() which returns a boolean value of true. I then have in the main class where the JFrame was instantiated an if/else if statement telling it to set the JFrame visible if exit is False, and dispose of it if true. Doesn't do anything. I'm guessing that's because either it's not bothering to check at all or I coded it poorly.
Any advice?
EDIT: Clarifying what my code is so far without posting it (600 lines of crap to get through). I have my main class Driver(). It's the fairly straight forward main JFrame 'form'.
Said class has several buttons to open up a new JFrame that performs a simple function. We'll name one of those classes (only have 3 total for the Secondary JFrames) Panel(int type) It extends JPanel.
I have a constructor set up depending that takes the int type and hides certain components in my Panel (tried to maximize the panel by combining similar functions). I have a button on the panel that is an exit button. But because the class itself is not a JFrame and does not instantiate itself, I can't dispose of it there. I have to find a way to do so in the main class.
That is my issue.
See Closing an Application. You can use the ExitAction for your JButton and it will be just like clicking the close button of the frame.
I have two seperate JFrames but when i click the X in the topright of one, it will exit out of the other also. I have an "exit" button near the bottom to do setVisible(false), but i still have the tendency to use the x button. How would i make it so that it doesnt cancel out of the entire project?
Also, how would i make it so that the second JFrame locks out of the other JFrame untill the second JFrame is closed, like how a popup message works
Don't give your GUI two JFrames. The GUI ideally should have only one GUI. If a separate window is required, then make it a dialog such as a JDialog, and this won't happen.
Also, how would i make it so that the second JFrame locks out of the other JFrame untill the second JFrame is closed, like how a popup message works
You are perfectly describing the behavior of a modal JDialog or JOptionPane. Just use 'em.
Later we'll chat about using CardLayouts to swap views in a single GUI.
Edit, you state:
Im using Netbeans form editor to create them faster but I only see JFrame and JPanel. Can I edit them in Netbeans? I'd rather not do them through scratch Java
You've touched on another zealous belief of mine, that this is yet another reason not to use a code generator when learning a library as one can get too tied into the code generator, that it prevents one from learning the library. I strongly advise you to put aside your code-generation tool and create by hand, referring to the tutorials and API. Then later when you get more familiar with the library, sure use the tool. By the way, an answer to your direct question here is to gear your GUI's to create JPanels, and then use these JPanels where and how you want them -- in JFrames, or JDialogs, or JOptionPanes, or swapped in CardLayouts, or JTabbedPanes or nested in other JPanels,... etc...
You should be using a modal JDialog, not a second JFrame, because JDialogs provide certain functionality such as not adding another window bar to the taskbar, and automatically setting focus when the parent JFrame receives focus. Modal JDialogs prevent user input to the JFrame while it's open, useful for an "Are you sure you want to exit?" dialog, for example.
As for one JFrame exiting the other, you probably have their default close operation set to EXIT_ON_CLOSE. If you do this:
jframe.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
jframe.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent we){
handleUserWantsToCloseWindow();
}
});
Then you can control what happens when the user wants to close, such as popping up a "Save Changes?" modal JDialog or "Are you sure you want to quit?" modal JDialog. Note that you have to manually dispose of the JFrame if you use this method.
I have a very simple JFrame window that contains one button: No.
In the main function I set setVisible(true); my JFrame and in the No button listener I want to close the window so I set the visibility to false: setVisible(false); and after that I do System.exit(0); in order to prevent possible memory leaks when running the program many times.
I have two questions:
Do I really need to System.exit(0); in the above case?
If I have this JFrame as a popup window, I can't really use System.exit(0); because this will terminate the whole program. So how can I properly close the popup window and stay in the main JFrame window? (Now I close it only by setVisible(false); and when I do it several times through the program execution, the program turns very slow).
use CardLayout
if is there real reason for another popup container
use JDialog with parent to JFrame, with setModal / ModalityTypes
create only one JDialog and to reuse this one JDialog by getContentPane#removeAll()
use JOptionPane for simple users interaction
put both together, above two points, to use CardLayout for popup JDialog with parent to JFrame, notice after switch from one card to another could be / is required to call JDialog.pack()
setVisible will cause slowdown
dispose will cause slowdown
System.exit will close entire JVM
Therefore, you should reuse a single JFrame or JDialog.
In the button's ActionListener, invoke frame.setVisible(false);. Then instead of creating a new frame just do frame.setVisible(true);. If you want to change the contents of the frame, there is the function frame.getContentPane().removeAll();.
Just add this: JFrame.setDefaultCloseOperation(DISPOSE_ON_CLOSE).
Note: The default option for JFrame is HIDE_ON_CLOSE.
You can use the dispose() method of the JFrame class to close the frame and release all resources associated with it, including its child components.
I have a parent JFrame it contain a JButton. functionality of that button is to open another window.
I want to restrict the focus of window, means after closing the second window's focus should come into first window(parent). And focus should not come to first window if second window is open.
You should make your second window modal. That said, you'd probably want to make it a JDialog.
yes its possible but workaround for two or more JFrames, but for full funcionalities is needed lots of code,
standard would be one JFrame and another TopLayoutContainers could be JDialog then you can easily play with parent and modalities, toFront , setAlwaysOnTop
As shinoku stated, you can use a modal. However if you have to use a JFrame, you have to implement a WindowListener for the new JFrame. In that implementation for the windowClosing() method you can say originalJFrame.requestFocus(). Of course, your constructor of the WindowListener must be supplied with a reference to the original frame as well.
I have several JPanels that contain buttons, labels, etc. that I want to switch between from a main JFrame. Currently I am trying to use the this.add(JPanelname); method and this.remove(JPanelname); with the validate(); and repaint(); methods
The problem is it will add the panel to the JFrame but it will not remove it. I am not sure how exactly to go about this.
Maybe you should be using a Card Layout.
Or maybe you should be using modal JDialogs. So whenever you click on the "widjet" a new window is displayed. Then when you close the dialog you are back on your main frame.
If you are constantly switching between JPanels, then a JTabbedPane may be the right thing to use. It should not be necessary to call "validate" or "repaint" when you add or remove a JPanel. Do you have a layout manager installed? Do you make sure to call add/remove only within the UI event thread? Also, typically one does not call "validate()" but rather "invalidate()" to invalidate the container for updates.