I have a QTableWidget with four columns. I want the user to be able to insert only integers in the first three and a double in the fourth.
I believe that this can be done with delegate, but I have not found relevant examples (only some with QDateTimeEdit).
What should I do?
Look at the documentation for QItemDelegate; it provides a pretty good description on how it can be used.
Since with a delegate, you'll be able to provide your own custom editor, I would suggest that you use a QLineEdit with a validator set using setValidator(). I believe the classes QIntValidator and QDoubleValidator will be perfect in this situation.
Related
Is there a DoubleField or LongField Vaadin 7? I see a TextField and PasswordField, so it sort of shocked me when I did not see fields for numeric types. This seems so standard, especially since GWT has such fields under the hood, that I feel like I am missing something.
Also, there are some numeric field add-ons, but most of them say they don't support Vaadin 7, which leads me to believe there is some standard way to do it in Vaadin 7 already. Am I missing something?
I couldn't find a way either but I created my own with a custom TextChangeListener. Basically you override the method textChange(TextChangeEvent event) to check if the value is valid. If it's not valid then you delete it. Just be careful to adjust the cursor appropriately. I created a listener for integers (with max/mins), one for doubles, percentages, etc. Basically any kind of number validation you need. The tricky part is managing the cursor position. I wish I had some sample code to show you but I don't have it available on my current computer, but at least this should give you a running start.
Good day!
There are instances of classes QListView and QTreeView.
Both of the instances loads data from model (QStandardItemModel).
QTreeView displays positions (For example: Chief, Manager, Developer, etc).
Clicking on the title of position a list of employees revealed.
QListView displays only positions of staff.
Question:
How can I display a full list of names of employees in QListView not showing their positions?
Which methods I need to override?
What can you advise in this situation?
P.S. Thanks!
I don't think you are going to be able to do that with a single model.
This thread suggests using a proxy model to flatten the original one without having to maintain two instances of that data. But the implementation pointed to (KDE's KReparentingProxyModel) isn't exactly trivial.
There is some documentation on proxy models, and the QSortFilterProxyModel might be usable in your context, although I think you'll need something more specific.
You might also find the classes attached to the third response on this thread: ModelView - how to use proxies to filter this data? interesting as a starting point.
(Sorry this isn't very specific. Searching for "qt flatten tree model" will give you other ideas.)
Try to use QListWidget, is easier than QListView.
Let's say I'm creating some app documentation. In creating a content type for functions, I have a text field for name, a box for a general description, and a couple other basic things. Now I need something for storing arguments to the function. Ideally, I'd like to input these as key-value pairs, or just two related fields, which can then be repeated as many times as needed for the given function. But I can't find any way to accomplish this.
The closest I've gotten is an abandonded field multigroup module that says to wait for CCK3, which hasn't even produced an alpha yet as far as I can tell and whose project page makes no obvious mention of this multi-group functionality. I also checked the CCK issue queue and don't think I saw it in there, either.
Is there a current viable way of doing this I'm not seeing? Viable includes "you're thinking of this the wrong way and do X instead." I've considered using a "Long text and summary" field, but that smells hackish and I don't know if I'd be setting myself up for side-effects. I'm new to Drupal.
There is the http://drupal.org/project/field_collection module but it's not yet ready. Right now you would need to implement your entity alas to do this :( not easy.
Not sure how well it would work, because it currently does a bit more (eg, forces to group pairs into categories and the keys need to be predefined) but you might want to have a look at http://drupal.org/project/properties.
You could create a these key-value fields on their own: create 2 regular fields that that can be added as often as needed.
So you have a x fields for the keys and x for the values. If this is only for you or other people it might work OK but usability wise, it's very ugly.
If you need to extract the fields from the function, to display it properly in a page template, you should propably use a different approach. Write the function with its arguemnts in a CCK field and in the template extract them as needed. The arguments are always (depending on language) in () and the different arguments are seperated by , so splitting them would by pretty easy.
What is the best starting point for a Qt4 widget for entering Latitude/Longitude in DD:MM:SS format (degrees, minutes, seconds)? Customize a QLineEdit? A series of spin boxes?
There are some variants:
QLineEdit with Validator - wasn't good enough for us, we couldn't achieve usable editing and proper view (with ', '' and degree symbols in place and ability to forbid incorrect values and still allow semi-correct states, and the target behaviour is not to mark errors and force user to fix them, but to allow user to enter only valid values).
Three spin edits in a line with the proper symbols between them grouped as a single widget and some code to move keyboard input from one no next when needed etc. Looks good enough in some cases, and you can find the variant of realization in the famous Marble project.
Still, my boss said that this approach is almost as ugly as first, so here is another approach: subclass QAbstractSpinBox, as Trolltech did in their QDateTimeEditor. In fact, behaviour of such a widget is near similar to one, implemented in QDateTimeEditor.
I, myself didn't do it yet, cause of task priorities, but will have to do.
I would use a QValidator, attaching it to a QLineEdit using QLineEdit::setValidator().
You'll need to subclass so you can implement the validate() function and possibly the fixup() function for your particular case, since the two validators included with Qt only cover integers and doubles.
It's a bit friendlier, in my opinion, to provide a single input box for this rather than three separate spin boxes (which could look cluttered and isn't as nice to type in).
[Edit: One other alternative is to set a "validation input mask" on your QLineEdit using QLineEdit::setInputMask(). You might want a line edit with symbols already in place and placeholders for other characters, for example, and this approach will give you something similar to that. The QtDemo app has an example of this which you can check out by choosing Widgets->Line Edits (Widgets is on the second page).]
I have a checkbox in a Flex DataGrid, and when I scroll, other rows are randomly checked/unchecked.
After reading over: Creating a column of RadioButtons in Adobe Flex
it's clear that the itemRenderers are getting recycled, but the problem I have with the solution presented there is it moves info about the view into the model.
Does anyone have a better way of solving it, that doesn't force me to put information for the UI into my actionscript model classes? (in my case, I am converting incoming XML data to actionscript classes, and these are getting bound to my datagrid).
Thanks for the help.
thanks everyone. great tips. unfortunately it was becoming too much overhead to keep the model pure, so i just polluted the model like the link in my original post. :( at least it works.
Chetan, neat idea.. i tried working with this for almost an entire day with no luck though.
brd6644, good thoughts on separating the two model classes.. i might go back and do this later.
You could create a subclass of DataGrid that internally stores what rows are checked/unchecked (Array/Collection of Boolean) but you would have a devil of a time keeping that in sync with the dataProvider when it is sorted or filtered. I suppose you could use a Dictionary that is keyed by the object in each index of the dataProvider and valued with a Boolean to indicate whether it's selected. That would at least isolate you from the sorting / filtering issues. This will not work if you have duplicate references in your dataProvider.
Alternatively, you could create a subclass of your ActionScript model class and add the "selected" property to it, then write some simple utility methods to "convert" between the two. That way your View deals only with the "ViewModel" class and other layers (especially the server side) deals only with the real "Model" class.
Adding to what cliff.meyers said, there is a third option of creating a custom IList class as described in this blog post by Alex Harui. It is pretty clever actually, and is cleaner as it doesn't require subclassing the component or polluting your model classes.