Functionnaly :
On one of my components of my application, I have an editing/lock system. When a user starts editing, he locks the file so other users cannot edit it.
Problem scenario : When the user activates "edition mode" and leaves screen, I would like to show a alert with two options : save changes, or discard changes.
There are different ways to exit screen :
There is a List on the left side containing other possible editabel data. A click changes the data in my component.
There is a menubar on top leading to other screens.
The edition component is embedded in a Tab navigator. When changing tabs, the alert has to show.
Closing browser.
Do I have to catch all of these events and plug at all those places?
Is there any kind of focusout mecanism?
The answer to the first question is: YES.
You need to watch all possible exit events that could harm the currently edited data.
Well, the problem is now how to manage this properly. Using an MVC framework you would trigger the appropriate commands from your components:
CHANGE_LIST_ITEM (new item)
CHANGE_TAB (new tab)
CHANGE_SCREEN (new screen)
Each command then checks if the currently edited tab has been saved or not. If not, it displays the Alert. Else, if there are no changes, it allows the list, the screen chooser and the tab bar to continue.
So your components (list, screens, tabs) need to implement some kind of rollback or preventDefault mechanism. Generally, changing their state must be allowed by a central validator (in MVC the command).
In the case of the list: I would suggest that the list is not selectable by mouse click but only programmatically. You set a listener on the list item click event. If the command allows setting of a new item it will notify the list. In MVC usually by sending an async message that gets received by the list's mediator. [[And even more correct: The command would set some model properties (e.g. currentListItem) and the model than sends an async message.]]
Edit: For the browser close event, you need to call a JavaScript expert.
Related
In my JavaFX application, at a specific page I have to initialize (when loading the page) some devices such as iris scanner, fingerprint scanner, cameras etc. Before leaving the page/controller it is necessary to deinitialize the devices. There are two buttons in that page. If the user leaves this page by clicking one of these two buttons I can easily deinitialize them. But if the user leaves the page by clicking any menu/sub menu (there are more than 30 menu and sub menu in this application), how can I deinitialize these devices?
There is no destructor in java and I also tried using finalize but nothing comes out.
You cannot rely only on the finalize() method. An answer to this request seems to show that this method is used by the garbage collector to check data loss references. So you need to destroy objects by-hand in a custom method, then finalize() will be automatically applied.
You must create a deinitialize() method (public or package-private, depends on the location of your MenuBar controller) then call it inside your sub-menu item.
I'm implementing a basic shape drawing tool using a custom subclass of Qt's QGraphicsScene and several QGraphicsItem. Now there are several situations where I don't want any "global" actions to be executed:
For example, while dragging items around, the user should not be allowed to create a new file or to undo the last action (by pressing Ctrl-Z for example) since this would lead to several problems that would have to be handled separately (if the user is currently drawing an edge between two nodes, what should happen if he presses Ctrl-Z with the last recorded action being the creation of the first node?)
I noticed that several commercial applications like Microsoft Word and Adobe Photoshop just seem to ignore any usual keyboard shortcuts while being in such an "intermediate" state. Furthermore, when dragging items out of the viewport, these tools display a "forbidden" cursor and do not allow any mouse press events to reach the outer window (like a right click on the toolbar, for example).
How should I implement this in my case, when using QGraphicsScene? I already tried to add the following override:
void MyGraphicsScene::keyPressEvent(QKeyEvent* keyEvent)
{
keyEvent->accept();
}
But any pressed keys were still delivered to the main window. In addition to that, I'm not sure if filtering just keyboard events is safe enough, since there might be other input events that could trigger forbidden actions.
Is there any generic approach to this problem that I could use in my software?
problem is I have a spark Tabbar, with many forms in each tab.
But I have a single global save button. Problem is, if I don't open a Tab,
it doesn't get initialized and therefore the forms it contains do not exist..
How Can I make it as if the user had clicked on every tab?
The best way to handle this is to have a data model that each tab is displaying and editing, rather than trying to go in and read the values out of the controls in each tab, and save those. This is at the heart of MVC.
However, if you're too invested in your current architecture to be able to change it and you are using a ViewStack with your TabBar, you may find that setting creationPolicy to "all" does what you want. If you're using States, I don't think you can force all of them to be instantiated without putting your application into each State at least once.
Flex application is being made accessibility compliant. When a custom component is made visible based on some condition, the first item (either text or formitem or textarea) inside the component is skipped by Jaws. It reads from the second item. On pressing UP arrow, the first item is then read.
Is there a way to make the first item accessible without need for pressing UP arrow?
This is likely going to be related to focus management.
You're likely going to want to assign componentId.setFocus() to the first component in the current view when the view state changes.
You need to re-assess the focus when the state of your display changes. If you post how you are managing display state I can suggest exactly how to trigger that via an event or in your custom state method.
Also, if that doesn't work, try this once your screen is ready / state changed :
focusManager.moveFocus(mx.events.FocusRequestDirection.TOP);
This is a question on edit form UI for a WP7 app:
I currently have my edit form fields set to 2-way binding which means that as the user changes them they save on edit and update the UI in the ViewModel (Method 1). So I don't need a Save button and there is no Cancel button (unless you code in logic to store the original state and rollback on cancel).
Method 2 would be to use 1 way binding and UpdateSource on the save button and then you could have a Cancel button which functions like the Back button (goes back without saving).
Method 1 is nice as it handles preservation of state if the app is tombstoned - WP7 will restore the page and your changes will have been saved. The downside is that there is no way for the user to restore it to it's starting state once they make changes. My form is trivial so I do not think this is a problem. The Back button acts as Go Back.
I also do calculations in the setter property in my VM that need to be reflected to the UI (ie you will in Field 1 and Field 2 is double the value (but they can also override it) - I use 2 way binding on Field 1 and update field 1 and 2 on edit. I can't think of a way to do this using explicit updating.
The problem is that I have a Delete button for the record, so when I use Method 1 with no Save and Cancel button the user is likely to click the Delete button as it is the only available option (they need to click on the Back button to go back).
My question is; should a simple form have a Save and Cancel button and commit the data only on Save, or is it ok to use 2 way binding and have no buttons?
Parts of this are mentioned in the UI Design and Interaction Guide page 68.
Changes to Application Settings should be immediately implemented. This
means that a “Done”, “OK”, or other confirming dialog is not needed.
...
If a task cannot be undone, always provide the user with an option to cancel. Text entry is an example.
Actions that overwrite or delete data, or are irreversable must have a “Cancel” button.
As for your situation you will need a confirmation for the delete action (see the ie settings for an example). For your other fields check the guide as other issues are mentioned and you could also see how the built-in settings work.
If it is possible that the user may ever not want to have their entered text changed it'll be easier to have a one-way binding and update the saved value only when the user specifically says to.
Yes, this can make the preservation of entered data slightly harder during tombstoning but means that it's easier fro the user to be able to change their mind.
In your situation, I'd recommend having on screen buttons for Save and Delete (and relying on the hardward back button for cancel).