I use Qt Designer to build my UI layout. On the layout, I have a combobox named cb_fac_cd. In my code I have a function that will automatically build a combobox based on the list I'm attempting to build. I have a lot of these lists defined in the database and this function spits out a QComboBox.
Unfortunately, until now I've only used this function to add cellWidgets to QTableWidgets. It works perfectly there. Now I want to populate this preexisting combobox.
It seems that a simple
self.ui.cb_fac_cd = makeComboBox('FACILITIES') doesn't work. I can see that the function returns the QComboBox as usual, but the cb_fac_cd combobox remains unpopulated.
How can I copy or assign the returned combobox to the one build in Qt Designer?
I am using PyQt, but that shouldn't make any difference.
As far as I know, you cannot replace objects which are part of the .h files generated by Qt's UIC mechanism (though I cannot confirm that 100% right now).
What I usually do in such cases is to have an empty layout in the ui file and then do the following:
(Note that I'm using Qt/C++ syntax as I don't know the pyqt syntax but I think you will get the idea)
QComboBox* pNewComboBox = makeComboBox( "FACILITIES" );
ui.pComboBoxLayout->addWidget( pComboBox );
Additionally, if possible for your program, consider using an enumeration rather than a string for your makeComboBox function. This is usually faster and safer.
It sounds like you should either
Change makeComboBox to populateComboBox(QComboBox *p) and pass it the combobox in your layout to fill, or
Create and add the QComboBox to your layout dynamically and remove it from your .ui
You can change the model from you Ui to the one you get from the other combobox:
tempCombo = makeComboBox( "FACILITIES" )
self.ui.cb_fac_cd.setModel(tempCombo.model())
But for that part:
I have a lot of these lists defined in the database and this function
spits out a QComboBox. Unfortunately, until now I've only used this function to add
cellWidgets to QTableWidgets.
If the data comes from a database, you might want to look at QSqlRelationalTableModel to avoid doing that manually.
Related
I am working in Qt4.7, and I have a QListWidget in my dialog. I have a QString that needs to match the current text in the row of this widget (the individual rows are editable). Looking at the signals associated with QListWidget, there seem to be signals for when a different index is selected but none for when the text of a the currently selected row changes. I thought currentTextChanged(QString) would do it, but it didn't. I also thought to try to connect each individual row to something, but QListWidgetItem doesn't have any built-in signals. Does anyone know of a way to do this? Thanks!
At first it seems like QListWidget::itemChanged is the way to go, but soon you run into a problem: the signal is sent for everything - inserts, changing colors, checking boxes, and anything else that "changes" the item! Predelnik pointed that out in his answer. Some people have tried to put in flags and filter everywhere by intercepting various signals to find out if editing was the actual event. It gets very messy.
There is also QAbstractItemModel::dataChanged , which would seem like a good solution. It even has a parameter "const QVector& lstRoles" so you could scan for Qt::EditRole and see if it was really edited. Alas, there's a catch - it gets called for everything just like QListWidget::itemChanged and unfortunately, for QListWidget anyway, the roles parameter is always empty when it's called (I tried it). So much for that idea...
Fortunately, there's still hope... This solution does the trick! :
http://falsinsoft.blogspot.com/2013/11/qlistwidget-and-item-edit-event.html
He uses QAbstractItemDelegate::closeEditor, but I prefer using QAbstractItemDelegate::commitData.
So make a connect like so...
connect(ui.pLstItems->itemDelegate(), &QAbstractItemDelegate::commitData, this, &MyWidget::OnLstItemsCommitData);
Then implement the slot like this...
void MyWidget::OnLstItemsCommitData(QWidget* pLineEdit)
{
QString strNewText = reinterpret_cast<QLineEdit*>(pLineEdit)->text();
int nRow = ui.pLstItems->currentRow();
// do whatever you need here....
}
Now you have a slot that gets called only when the list item's text has been edited!
I guess you need to look into the following signal:
void QListWidget::itemChanged(QListWidgetItem * item)
But be careful because it's being sent every time some property of item changed, not only text. I remember when we ran into the problem once when we changed item colors and got tons of false positive slots called because of that. If you need more fine tuning I guess it's better to write model/view classes yourself and not rely on QListWidget.
I'm implementing a Model/View for a tree like structure, and I've decided to try the QStandardItemModel on which I want to wrap on it a specific class, (which I call here "appSpecificClass").
Basically, I want part of that class (like names, or some data), to be shown in the model, and when I change the model (in edit role, or drag and drop), I want that to have consequences on the appSpecificClass (which is, when I change a name that is showing on the model, the name on the object associated with the model's item of the appSpecificClass also changes).
So, I started from subclassing the QStandardItem by a appSpecificItem, which only has a pointer to the appSpecificClass. When I construct the appSpecificItem, the text and icons are called from appSpecificClass and everything works fine.
However, when change data from appSpecificItem, naturally it does not change the appSpecificClass, because so far I didn't found any way of interacting with the appSpecificItem's pointer via overloading a virtual function (or else)
Does anyone knows how to do this/if this is possible? What can I do such that if for instance the signal
QStandardItemModel::itemChanged ( QStandardItem * item )
is emitted, I can change a the appSpecificItem's pointer.
If not, is there any good tutorial about implementing a Model from scratch? I've tried myself some, but it is not an easy task. Ideally I would like a QStandardItemModel like model, but a little more abstraction on it (such that I can put my appSpecificClass on it).
I'm trying to write a script for an application developed with Qt, using javascript for the business logic and a .ui file for the GUI, but I'm facing two problems.
In the ui I declared a QComboBox, to which I successfully connect javascript functions to handle
signals such as editTextChanged, etc. I was wondering I cannot populate the combobox from within
javascript code, because the addItem function is not exposed to script-side code.
combobox.editTextChanged[action](ComboBoxChanged); // OK (action is "connect" or "disconnect")
combobox.addItem("element 1"); // Error!
Is there any (other) way to do this?
I need to show a set of items (strings) in a table-like component. I tried using a QTableView and
QTableWidget but I cannot insert or get items. For example, from javascript I cannot access the
setModel function of a QTableView (if at least I could create a QAbstractItemModel from
script...), neither I can access the item(row,col) function of a QTableWidget class, to set an
item's text. Is there any way to show a table of strings to the user, let edit them and retrieve
the modified contents?
Thanks in advance.
Antonio
Because the addItem() function isn't a slot, you'll need an intermediate public slot to handle the transaction. It'll be the same with the other functions you are trying to get at as well.
This is a Qt-specific question.
It's convenient to be able to add new data to a table by typing content into a blank row at the bottom of a table. When the data is committed, a new blank row is added to the table.
Has anyone found a way of implementing this in a generic way, that fits into Qt's model-view programming architecture? My closest attempt involves creating a proxy model, such that the rowCount() returned from the model is always one greater than the source model.
QAbstractTableModel* sourceModel ; // Data is stored here
QBlankRowModel* model ; // Proxy model that adds one to rowCount()
QTableView* view ; // View
view->setModel( model ) ;
model->setSourceModel( sourceModel ) ;
Any suggestions are welcome. Thanks.
From a design-perspective, this should be part of the view, not the model. Therefore, I suggest implementing a view with the functionality and leave the model unchanged. KOffice Kexi does just this with kexitableview (screenshot, documentation). Maybe you want to use some of their code.
BTW, you might still be able to use your hack and combine it with my suggestion by putting it inside a new table view implementation YourTableView:
QBlankRowModel re-implements the
QAbstractTableModel
interface. It returns sourceModel.rowCount()+1 as the QBlankRowModel::rowCount().
It returns a QVariant() if the n+1th row is requested in QBlankRowModel::data().
All the rest within QBlankRowModel is forwarded to the sourceModel (with editing
the n+1th row in QBlankRowModel buffered and replaced with inserting into the
sourceModel when finished).
The new YourTableView inherits from
QTableView and wraps the sourceModel within
YourTableView::setModel(), calling
QTableView::setModel(QBlankRowModel(sourceModel)).
Thereby, your hack is localized at one point.
Your solutions seems a little hackish. Your problem is not only additions, it's also editions. What happens when your user edits a row, the typed data goes directly to your "data layer" even before the user commits his edition?
A better solution would be to restrict the role of your sourceModel. Rather than being a "direct" representation of your data, it should be a "buffered" representation of it. When the sourceModel is created, you make a copy of your data in some kind of Row() instances. The sourceModel, having its own copy of the data can then freely play around, perform editions and additions, and only commit the data to your model layer when the user commits his edits.
If you want a PyQt example of such a table, you can look at the source of a project of mine:
http://hg.hardcoded.net/moneyguru/
You might have to dig around to actually find the "buffering" logic because it's not in the PyQt code itself, but rather the "cross-platform" part of the code:
http://hg.hardcoded.net/moneyguru/src/tip/core/gui/table.py
This logic is then used in my QAbstractItemModel subclass:
http://hg.hardcoded.net/moneyguru/src/tip/qt/controller/table.py
Sounds like a reasonable solution, as it should work for any model that you might want as the actual table model, ie. SqlTableModel or just a plain one. As long as you add the row when the user is done editing and take care not to add the row when the user did not add any data.
I am using QT4 and dynamically adding entries to a QMenu. Is it possible to sort the entries in the QMenu without deleting it and creating a new one?
I originally thought there was a function to insert at a specific location so I could sort on insert, but I have not been able to locate it.
Once added, I don't think you can reorder. While you are creating though you could use the QWidget::insertAction method to place it exactly where you want it.
void QWidget::insertAction ( QAction * before, QAction * action )
Otherwise you could use QWidget::addActions. Create your list of Actions and sort it before adding to the QMenu.
void QWidget::addActions ( QList<QAction *> actions )
In one of my codes, I save the QActions into a separate List and generate the menus and submenus on demand. In theory, I can add "weight" to the items and have them re-ordered, but I have not implemented this yet.
Project page is available here: http://code.google.com/p/qtedit4/wiki/qmdilib
Please note that the actions of QWidget (and QMenu) are stored as a QList which can be "read", using QWidget::actions() . Remember that the list is copied, so you can modify the actions but not the list itself. (I hope I am not mistaking...)