I have an applet. In this I have a JLabel component. When the user clicks this label, a new JFrame component gets displayed. I want to set the value of setDefaultCloseOperation() for this frame as JFrame.EXIT_ON_CLOSE. However, I get a SecurityException if I do that. I read the documentation of JFrame.EXIT_ON_CLOSE and its written that :
The exit application default window close operation. If a window has this set as the close operation and is closed in an applet, a SecurityException may be thrown. It is recommended you only use this in an application.
What I understood from the above is that if a frame is closed without specifying default close operation, the frame is only hidden. I want to close the frame when the user tries to close it, and not hide the frame. Is this possible?
You are not allowed to exit the application in an applet, Rather you can use DISPOSE_ON_CLOSE which removes the JFrame completely.
Related
I am creating a MATLAB application in GUIDE and now I'm facing a problem. I need to call a function that takes a long time to execute and returns a value but while executing the function I want the GUI to wait for the returned value.
I tried with waitfor but this way I can still interact with the GUI and I can't take the returned value...
waitfor(function);
I can think of something that disables all the GUI then enables it back but I have both enabled and disabled objects...
Do you know any solution to this problem?
A simple solution is to create a modal dialog box with a message "Please wait..." just before executing your long-running function, and then to close the dialog box just after it completes. A modal dialog will be in front of the GUI, and will not allow interactions with the window behind.
It's possible for the user to click the "Close" button on the dialog, but you can override this by setting the "CloseRequestFcn" property of the dialog, so that the close button does nothing (unfortunately you can't easily hide the button).
I like the modal dialog proposed by Sam Roberts. There is no mystery and it is user friendly.
Another dirty and easy solution may be to hide the GUI completely, if it is okay:
set(hFig, 'Visible', 'off');
And set it to 'on' after done. It will be good practice to make sure to set it to 'on' in catch block, to avoid disappearing GUI due to error during execution.
Is there a property that tells if a form is deactivated by other form ShowModal procedure ?
EDIT :
My program has a tray icon that brings to front the main form when it's clicked. I want to disable this when another window is shown in modal state. Because not doing so the main form (which is disable) will cover the modal form and completly block my program.
This behaviour is to be expected. When a modal form is shown, the other forms are disabled. You don't need to disable anything at all, the framework already handles it all for you. The beep is sounding because you are attempting to interact with a disabled form.
If you want to be notified when your window has been disabled, for any reason, not just because a modal form has been shown, listen to the WM_ENABLE message. To test whether or not your main form has been disabled. Do that by calling the IsWindowEnabled Win32 function.
Having said that I feel that it is likely you've not diagnosed the issue correctly. It sounds like you might be suffering from window ownership problems, which are common in Delphi 6. Or perhaps you are attempting to restore the application incorrectly from your notification icon code. Use Application.BringToFront for that.
The VCL's handling of modal dialogs seem very mixed up. When you show a system provided modal dialog, e.g. MessageBox, windows are disabled whether or not they are visible. However, the VCL only disables visible windows when ShowModal is called. What's more, you cannot use Enabled to test whether or not the window is disabled, you must use the IsWindowEnabled Win32 function.
You can test Application.ModalLevel at any point in time to find out if there's a modal form. E.g.:
if Application.ModalLevel = 0 then
MainForm.Visible := True;
Note that non-TCustomForm descendants will not set modal level, API dialogs like a file open dialog or MessageBox for instance. If there's a possibility of such a thing, you might surround code that runs those dialogs with ModalStarted and ModalFinished.
It doesn't seem necessary in your case, but if you somehow need to be notified that a form/dialog is going modal, you can attach a handler to Application.OnModalBegin and Application.OnModalEnd events. You can use an TApplicationEvents component for that.
As you know there is no Close method in DialogBox. Look at this code:
myButton.addClickHandler(new ClickHandler() {DialogBox myD=new DialogBox(); } );
There's a hide button in DialogBox myD, so when users click Hide, the system will call myD.hide();
Look at this action:
User clicks myButton, then myD popup, then the user clicks Hide button to hide myD
Will server's memory waste if the user does the above action many times?
Will it create a lot of garbage in the server's memory? if it will, then how to code DialogBox properly?
The GUI of your GWT projects is running on each client. GWT transforms your Java (client) code into HTML, JavaScript and CSS . These are all client based techniques. So the server memory usage is not affected by your GUI, if you do not call any logic on the server.
You're using the browser memory, not the server one.
Try declaring DialogBox myD; in your class and reusing the same instance. The hide() method javadoc says:
public void hide()
Description copied from class: PopupPanel
Hides the popup and detaches it from the page. This has no effect if it is not currently showing.
But widget creation is time and resource consuming. You can keep it if the popup is not used a lot (always the same equation: either more development and better programs, or less development and more resource consuming program)
private ImgButton button = new ImgButton();
...
button.setSrc("iconName.jpg");
GWT or SmartGWT, I cannot tell exactly, generate state word to concatene it on the name of file.
Example to clarify :
On focus, iconName.jpg become iconName_Focus.jpg
On mouse down click, iconName.jpg become iconName_Down.jpg
On over, iconName.jpg become iconName_Over.jpg
Because these images are custom images, I want to tell GWT to take a default image when I didn't provide the corresponding image.
For example, when over event is fire and iconName_Over.jpg does not exist then use iconName.jpg.
Use the setShow{State} or setShow{State}Icon methods accordingly. For example for disabling the mouse down state, use setShowDown(Boolean.FALSE). For not showing a different icon when the mouse goes down on the button, use the setShowDownIcon(Boolean.FALSE). The rest of the actions have accordingly named methods you can look up at the ImgButton's javadoc page.
In my HTA, I hold it it open if an error occurred, and close it if everything was successful. At the start, I have the sysmenu property set to no because I do not want the user to close the HTA until it's finished. At the end, I want them to be able to click on the close button. Here's what I typed up to try to achieve this, but it doesn't seem to work? I suspect there is something I need to do to get the HTA to refresh it's windows properties?
Please note that any solution that completely reloads the window and/or makes the script execute again is not acceptable
If Not bHoldOpen Then
Call window.close
Else
Dim tagHTA
Set tagHTA = document.getElementsByTagName("hta:application").item(0)
Call tagHTA.setAttribute("sysmenu","yes")
End If
You cannot change it at runtime, its only available in the HTA: block as its value is used to determine how the physical window is to be initially created.
I thought you could produce a warning using the onBeforeUnload event & call cancelBubble to abort the close, but I tried it in IE8 and it still seems bugged; http://support.microsoft.com/kb/946214.
It would probably be simpler and easier for the user to comprehend if you were yo just unhide a "Close" button when the process completed.