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.
Related
I'm developing an application using java swing. When I click a button, I want another window to be opened. This works fine. But it is possible to alt+tab to the original window and then interact with it even after the new window is open. Is there any way not to let the user focus the original window after the new window appears? By window I'm referring to Jframe/Jdialog.
Assuming the instance of your main JFrame window is called mainWindow:, the following code will prevent switching the focus.
// the second parameter makes the dialog modal and will prevent
// switching the focus to the mainWindow
JDialog dialog = new JDialog(mainWindow, true);
...
dialog.setVisible(true);
Documentation on JDialog: http://docs.oracle.com/javase/6/docs/api/javax/swing/JDialog.html
You may try to use a JDialog instead of JFrame and pass the instance of JFrame to JDialog constructor
You may also try to check
frame.setAlwaysOnTop(true);
or may be like this:-
frame.toFront();
frame.setState(Frame.NORMAL);
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 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've created a simple Swing panel that, when loaded, takes up my application's entire window. It contains two JTextAreas and a handful of buttons. I want one of the text areas to have the focus when the panel loads, so that the user can immediately start typing instead of having to click on the text area first. How can I achieve this?
By default focus goes to the first component defined on the window.
If this is not the component you want to have focus then you need to request focus once the window is realized.
The Dialog Focus example shows a couple of ways to do this.
See here the Documentation which contains exactlly what you are searching for (I think):
A component can also be given the
focus programmatically, such as when
its containing frame or dialog-box is
made visible. This code snippet shows
how to give a particular component the
focus every time the window gains the
focus:
//Make textField get the focus whenever frame is activated.
frame.addWindowFocusListener(new WindowAdapter() {
public void windowGainedFocus(WindowEvent e) {
textField.requestFocusInWindow();
}
});
You just need to call requestFocus method of Jcomponent class,
public void requestFocus()
On the Component that you want to focus.
And pleas make sure that you call this method after setVisible is called for its parent component.
For example:-
You have a Jframe in which you added a JTextArea, so after calling you should call in following order:-
jframe.setVisible(true);
jarea.requestFocus();
I have two JFrames. Both are visible at same time.
One JFrame takes the whole screen..its just plain white. (it is acting as a background). And other JFrame is a small box with buttons/texts and other swing components.
The problem I get is when I click the big JFrame area, the JFrame box minimizes. So how do I specify java to make sure the JFrame box is always on top of the JFrame background?
Use a JInternalFrame
Make the JFrame box a JPanel box.
Your application should only have one JFrame.
JFrame is a TopLevel Component and therefore usually you don't put a JFrame into another. If you want to put your smaller jframe into your bigger I would subclass either JDialog or a JPanel.
In general, an application should only have a single JFrame. Other windows should be dialogs.
The problem I get is when I click the big JFrame area, the JFrame box minimizes.
When you use the dialog make sure you specify the frame as the owner of the dialog:
JFrame frame = new JFrame();
JDialog dialog = new JDialog(frame);
If the main frame is ever minimized, the dialog will also be minimized. When the frame is restored the dialog will always display on top of the frame.
use Jdialog with setModal(false) for your small window ,
probably you want something similar to gimp
look at gimp toolbox , only X at title , means its a Dialog.
hope that's help