I have written a program where the user can select multiple rows from a QListView. Sometimes the program need to load a set of selection at startup, so the program needs to be able to select multiple rows from code. How can this be done?
you can use QItemSelectionModel class to manage the view selection and modify them.
from document :
Whenever you want to modify the selected items use select() and provide either a QItemSelection, or a QModelIndex and a QItemSelectionModel::SelectionFlag.
Related
I want to know how to change the order of QTableView rows by dragging, and store the order changes to the model?
I use QTableView as view and QSqlTableModel as model. I am using Qt 5.15.
I set:
ui->table_view->setSelectionMode(QAbstractItemView::SingleSelection);
ui->table_view->setSelectionBehavior(QAbstractItemView::SelectRows);
ui->table_view->setEditTriggers(QAbstractItemView::NoEditTriggers);
Methods I tried:
1.
ui->table_view->setSectionsMovable(true);
ui->table_view->setDragEnabled(true);
ui->table_view->setDragDropMode(QAbstractItemView::InternalMove);
ui->table_view->setAcceptDrops(true);
It doesn't take effect. The row cannot be dragged.
2.
ui->table_view->verticalHeader()->setSectionsMovable(true);
ui->table_view->verticalHeader()->setDragEnabled(true);
ui->table_view->verticalHeader()->setDragDropMode(QAbstractItemView::InternalMove);
ui->table_view->verticalHeader()->setAcceptDrops(true);
The row can be dragged by vertical header. But the order of changes will not affect the model.
As far as I know the QTableView does not call moveRows method of the model by itself. Instead drag and drop actions call *mimeData methods.
So, one option would be the following:
In your model you need to implement mimeData and dropMimeData functions. When you drag and drop a row the view will ask for mimeData() of the given row. If you are sure that you need only internal moves you can encode the selected row indices to QMimeData. Then in the dropMimeData() you decode the indices that were selected and use them to call your moveRows() implementation. Return false from this function to prevent removing of the moved out rows.
Another option can be to override the QTableView methods such as dropEvent() in a way, that it calls the model moveRows() method directly.
I have custom QTableView class that shows content of custom model based on QAbstractItemModel. In the model I've implemented all needed methods to support changing rows order by DragAndDrop ( using dropMimeData()).
But I do not know how to update selection in the view after model (and view) changed.
For example:
user clicks on the row, it becomes 'selected';
user drags this row to other place;
rows are swaps in the model and view;
BUT selection stays on the first selected row.
How model can notify view to change selection?
NOTE: I cant to create additional signals and slots because don't use MOC.
The solution is:
In function dropMimeData() need to use beginMoveRows() and andMoveRows() around place where data changed.
Need to process signal QAbstractItemModel::rowsMoved of the model, where we can retrieve index of the target row.
Currently I want to update row items in a QStandardItemModel without losing the sort order and row selection in the respective QTableView.
I have tested two approaches:
Clearing the model by clear() and re-adding the rows "destroys" everything including headers.
Removing and re-adding all rows keeps the headers, but still "destroys" selection and sort order.
I could try to manually to a) remove all rows no longer required and then b) update the items of the changed rows. But is there no easier way?
I don't know, how you sorted your data before the update, but please take a look at the QTableView's sortByColumn() function.
As for the selection, if it still keeps disappearing, you can manually put back your selection, where it should be by:
// You access the selected index when the editing starts
QModelIndex index = table->selectionModel()->currentIndex();
//Later when you finished editing, you can select it again
table->selectionModel()->select(index, QItemSelectionModel::Select);
More about this:
QItemSelectionModel
QTableView
You can either remove the rows no longer required and add the new ones or manually remember the sort order and which items were selected before clearing. I.e. assign a unique ID (one can use setData() with a custom role for that), retrieve that before clearing from the selected items, and reapply the selection after recreating the items.
I am trying to build a 6x6 grid layout. In each cell, there will be an input check box. I want to bind the checkboxes to my backing bean in a "consecutive fashion"...meaning, I would like to be able to iterate over the checkboxes to see whether they are checked or not. Basically, there must be an underlying data model. For example, you can drag over and drop off as a table, any item in the data control palette. Then in my application module, I can modify the view object as I wish before I save to the database. Now if I have a table with 36 rows and two columns (one is Id, one is Numeric (1 or 0)). I would like to drag over that table and drop off as a Grid that will enable a user to update each of the rows by selecting or 'un-selecting' a checkbox.
Try to use for each or Iterator component. They iterate over some array/collection and repeat elements enclosed within those components. You can check how Oracle does Dynamic Table (when you drag view object instance from application module to a page, choose dynamic table option) to get and idea.
try :
http://jobinesh.blogspot.com/2010/06/model-driven-approach-for-building.html
http://blogs.oracle.com/shay/2010/10/adf_faces_dynamic_tags_-_for_a.html
also try google with "dynamic form adf"
I have a need here regarding multiple selection of items in the QTreeView. I have two widgets, QTreeView on left and another QGLWidget on the right. If I do a multiple selection, I must highlight the items in the glwidget. Vice versa, I need to highlight the items in the tree view if multiple selection is done on the glwidget. Currently, I am able to update single item by setting the current index of the tree view. Any ideas on how to update the selection of multiple items on the tree view with multiple selection on glwidget?
You can use the tree view's item selection model (treeView->selectionMode(), of type QItemSelectionModel). It has a signal selectionChanged() you can connect to to receive tree view selection changes and apply them to the GL view.
When receiving selection events from the GL view, you can use QItemSelectionModel::select() to propagate them to the tree view.
To enable multiselection on your treeview, call setSelectionMode( MultiSelection ).
Frank was faster, but I still post my (untested) code example for adding an item to the current selection:
treeView->selectionModel()->select(
treeView->model()->index(row, column, parent),
QItemSelectionModel::SelectCurrent);
There are other selection modes too, see the QItemSelectionModel reference. SelectCurrent is a short-hand for Select | Current, so means update current selection by selecting the given items. It does not mean "select as current selection" (replacing previous selection).
In Python (PyQt6) I do :
ui.my_treeView.setSelectionMode(ui.my_treeView.selectionMode().MultiSelection)
It works well.