How can I restrict the user from going away from the current tab. I need to show a confirmation message to save/discard changes before leaving the current tab. How can I implement this functionality in a JTabbedPane?
You could override the setSelectedIndex in the JTabbedPane object, as this is called before the change takes place. If you do this, remember to call super.setSelectedIndex after you displayed your confirmation.
Alternatively, as Eng.Fouad states, you could add a ChangeListener and display the confirmation message there, but this happens after the tab has been changed, so your confirmation message would display after the new tab has been displayed on screen:
http://www.java2s.com/Tutorial/Java/0240__Swing/ListeningforSelectedTabChanges.htm
The second option would be easier to implement if you can live with the fact that the new tab will already be displayed when the confirmation pops up.
Related
I have a pretty basic interface of a chromotagram viewer. In the menu I allow the user to reverse the viewer with a JCheckboxMenuItem. Functionally, it does exactly what its supposed to do. My interface allows for multiple chromatograms to be open at once. I will post a few example pictures as I get to my question.
Above I have one tab opened and have yet to reverse the chromatogram.
Above I have clicked the option and it worked.
Here is my issue. If I open another tab and move to it, the option is still checked even though I have yet to click that button. The easy way out would be just to make it a normal button but I just want to know if there is a way that each tabbed could keep track of if its been reversed yet. Would this require multiple instances of the button itself? If anybody has any suggestions, please let me know. Thank you.
if(centralPara.getNumOpen() > 1){
centralPanel = centralList.get(centralPara.getCurrentFrame());
JCheckBoxMenuItem reverseItem = centralPara.getReverseItem();
boolean reversed = centralPanel.getReversed();
reverseItem.setSelected(reversed);
}
in my tab change listener I check to see that we have atleast more than one tab open. if so get the frame we are currently viewing and the top level menu item. Force it be be selected if that the current view frame is selected, or else force it be unselected.
I know I can add a ChangeListener to detect when the tab changed, but I would like to do it before it changed. Here's my situation:
when my user tries to switch tab I do a validation some content on the current tab and the tab should switch only if the validation passes. If I use addChangeListener and switch it back upon validation failure (hoping that it happens fast enough that I won't see it) I will see the tab switched and then immediately switched back which looks stupid.
Something within JTabbedPane is responding to tab click for sure that triggers a state change, I just wonder if this functionality is exposed outside of the class. Either way, is there a good solution for this?
Thanks in advance
Here is a nice approach to do validation before switching tabs by creating a custom VetoableSingleSelectionModel:
Forbid tab change in a JTabbedPane
This is a crosspost to the thread in Javaranch (includes some images): http://www.coderanch.com/t/567472/GUI/java/Optimal-solution-creating-multiple-dialog
I'm trying to develop a simple swing desktop application where I imagine alot of different dialog's jumping around to fetch user input. Would need to present labels, textfields, passwordfields, combobxes, checkboxes etc in various dialog windows.
For example: creating the database firsthand, creating the first admin account, adding users, changing user accounts etc.
I have an understanding that JOptionPane is used to create simple quick & easy modal dialog's. I would really like to know why one would choose one over another in this case. Which one is more preferable to use: JOptionPane vs. JDialog
Also I could use some pointers how one should appropriately design and implement this.
Thank you.
Here's a statement I found on the Java website that says one key point about the difference between the two.
How to make Dialogs
A Dialog can be modal. When a modal Dialog is visible, it blocks user input to all other windows in the program. JOptionPane creates JDialogs that are modal. To create a non-modal Dialog, you must use the JDialog class directly.
So it sounds like you would use JOptionPane if you want a user to have to make a choice and close the box before returning to the main screen. If you use a JDialog box, then they can just click around it and get back to the main screen without making a choice. For example, say you wanted to make a user choose the number of results before clicking submit, you wouldn't want them to be able to click around that window and click submit. You would use JOptionPane to force them to select a value first before going back to submit.
Check out http://docs.oracle.com/javase/tutorial/uiswing/components/dialog.html it pretty much has everything you would need.
As i understand it, JOptionPane is great for what it can do, but you can't really change the functionality beyond that (not easily). JDialog is better to inherit from if you want to create your own custom Dialogs.
Wow, what a stupid question you might say. But is it possible? I have a mouse move event in a Jpanel and it works even when the application is not in focus, now can I have something like that for the clicking event or something similar. And most importantly I don't want other apps (even something like the main menu) to lose focus when i click on my app.
I thought of the system's event queue but i'm not sure where that would lead me to.
Thanks in advance.
[EDIT - the purpose]
I want to create an app that mimics the users interactions with the system in a later time. for example a user takes the mouse and clicks and writes and my app will mimic that in say 2 hours time. ofcourse i would need a system hook for the outer events but i wanted to avoid os-dependant code so i basically capture the screen, take it to my app,for example the user clicks on an icon in the captured picture and then for making that come to life, i translate the coordinates to the real icon and click it (with a Robot) and in this way i can capture the user's events in my own app. the problem occurs when the user clicks on the main menu or right clicks (he's doing that in my app, and my app does that to the system so my app is in between) and ofcourse the real main menu will lose focus when the user tries to click on one of it's items.
sorry for my english.
I'm still not sure I follow what you are trying to do. But the concept of an app getting focus when you click on it is fundamental to the GUI and I suspect rather difficult to get around.
I just found this:
Focusable Windows
To support palette windows and input methods, client code can prevent a Window from becoming the focused Window. By transitivity, this prevents the Window or any of its descendants from becoming the focus owner. Non-focusable Windows may still own Windows that are focusable. By default, every Frame and Dialog is focusable. Every Window which is not a Frame or Dialog, but whose nearest owning Frame or Dialog is showing on the screen, and which has at least one Component in its focus traversal cycle, is also focusable by default. To make a Window non-focusable, use Window.setFocusableWindowState(false).
In this doucment http://java.sun.com/j2se/1.5.0/docs/api/java/awt/doc-files/FocusSpec.html
That sounds like it might do what you want.
I am working on a project that is using a JTable to display, among other things, a column of dates. We needed validation for the user input for dates, so I have implemented a combination of masking for format validation and parsing for actual date validation. I have done this using a custom CellEditor for the date column.
Inside my MaskedCellEditor, I have a JFormattedTextField. I setup the masking for dates. Then I add an InputVerifier to allow for actual validation. My InputVerifier implements verify() to check: 1. textField.isEditValid() 2. DateValidator.ValidDate(). If either is invalid, verify returns false and the InputVerifier locks the focus into the text field (the cell editor) and a small message dialog is displayed reminding the user of the date format.
The error message is a small, undecorated, non-modal, non-focusable JDialog that pops up underneath the cell being edited. It disappears on a keypress or a successful date verification. It is working great except for a small edge case.
If the user selects a menu button on the top of the application while an invalid edit has popped up the dialog, it switches screens, destroying everything currently on the screen (including the table). However, since the dialog is being shown and a keypress/successful edit has not occurred, the dialog is never hidden. It remains visible in a completely unrelated context on a different screen. Once the user has switched off the screen with the table, there is no way for the user to get rid of the dialog.
I have debated throwing either a Timer and/or a MouseListener on the dialog itself that would cause it to disappear, but I feel that I am ignoring the actual problem. The dialog is never being disposed of and I am pretty sure its because it is still set to be visible and it is preventing the garbage collector from getting rid of it.
I have a Cleanup method on the panel holding the JTable, but I cannot find a good way to reference the dialog (a component of the InputVerifier) in order to get rid of it. The dialog is pretty far removed from the table's parent panel. (Panel -> JTable -> CellEditor -> JFormattedTextField -> InputVerifier -> JDialog)
Any ideas on how to force the dialog to be hidden when the table is destroyed? If you need more details, let me know. I'm trying not to get you guys bogged down in the details, but there is a lot going on.
As a first thought, can you not go down the listener approach. If you have a closeErrorDialog() type method that gets called when upon successful valdiation, then you can also call it when a menu action is selected.
As an alternative, perhaps you could control the transition from menu to menu in some way, and create a "cleanup" method which will close down any exisiting error dialogs. This would allow for any other actions that need to take place when changing menus, to happen in the same place.
Just a couple of quick ideas of the top of my head. Hope they are along the lines of what you meant
Many people will vote me down for saying this, but it sounds like your dialog should be modal so that users can't switch away from it without dismissing it first. Or at least disable the menus that allow people to switch away while this dialog is displayed.