I have a model in c++. I want update Tableview when model changed. I have a problem. Model and Tableview is different threads. I need a signal that reload page with QML Tableview
I create new thread and new object. When doWork finished i emit signal with result
Related
I've found this, but it is only about QWidget based project. What about ApplicationWindow components in QML?
Finally I've connected to frameSwapped signal of the main top-level QQuickWindow of my application. It is called right after each repainting is done. So, after first repainting, my slot would be called, and I will start to really load the data (what is rather slow). Inside this slot I'm destroying this connection, so I don't slow down the application.
//main.cpp
QQuickWindow* mainWindow =
qobject_cast<QQuickWindow*>(engine.rootObjects().first());
QMetaObject::Connection loadingFinished =
QObject::connect(mainWindow, SIGNAL(frameSwapped()),
&controller, SLOT(construct()));
controller.setConnection(loadingFinished);
//Controller.cpp
void Controller::construct() // this is slot
{
// some really long operation
disconnect(*m_loadingFinished);
}
Hope it will be helpful for someone.
In my program I use QTableView and QAbstractTableModel that are connected. Model doesn't contain data. When view needs data to show it calls QAbstractTableModel::data and model uses another object to get data and return. At some point data in that object is going changed. Model doesn't know what has changed so dataChanged is not called.
I need that only visible part of data (that is shown in view) goes updated. It should get new data from model. I am trying to achieve that by calling update() or repaint() functions of view but it doesn't help. I am thinking that it should call paintEvent of tableview but it is not called.
How is it possible to make view update visible part of data? I don't want to update whole data that is huge.
Your wishes brokes Qt MVC logic. But if you need workaround - you may do next call to update visible area: emit dataChanged( QModelIndex(), QModelIndex() );
I have a model which is updated dynamically not related to the view. Which method should be called on the view to show the current models data?
Example:
StationListModel *model = new StationListModel(dynamic_list);
QListView *view = new QListView;
view->setModel(model); //view set with empty model
view->show();
In some point in time the dynamic_list is populated with new entries via a socket connection (nothing to do with View). How to populate the view with new data?
Model must emit signals to notify views when its data changed. Choose appropriate signals depending on how exactly data is changed:
dataChanged signal forces view to update specific cells, but not to create or remove cells.
layoutAboutToBeChanged and layoutChanged signals forces view to update everything.
signals about adding or removing rows and columns forces view to update accordingly.
I just switched from QTableWidget to QTableView. Calling the method setSortingEnabled before filling the table slows the construction really down. So if I use QTableWidget I first fill the table and then I call setSortingEnabled.
My problem with QTableView is that I do not know how to find out that the Table is filled, resp. when to call setSortingEnabled without loosing performance.
Is there any signal I can handle, or any slot to override ?
I have an application that displays an editor for a diagram using QGraphicsScene object. I would like to create a read only version of the same dialog but have ability for user to see both at the same time.
SimScene* pScene1 = new SimScene(model); // adds model to scene
SimScene* pScene2 = new SimScene(model); // adds model to scene
QGraphicsView* pView1 = new QGraphicsView();
pView1->setScene(pScene2);
QGraphicsView* pView1 = new QGraphicsView();
pView2->setScene(pScene2);
When I create 2 instances of QGraphicsScene and use addItem on the second one it removes all the items from the first one. Does Qt support any sort of sharing of model between scenes? Is my only choice to have same scene and try to customize the view? Later one doesn't seem to work because object selection information is within the graphics items being shared so if I disable flags on them they become read only in both views. Any advice is appreciated. Thanks.
If you just want an interactive and a read-only view on your model you can use a single QGraphicsScene and 2 QGraphicsViews. You just have to call QGraphicsView::setInteractive(false) on one of them. That way you don't have to change any item flags.
I think that you're storing QSceneItems in model classes. Because of that pScene1 and pScene2 are trying to share not only the model itself, but also the scene items. This won't work because any scene item can be placed only on one scene at any given moment.
How to fix it? Make model not aware of any GUI. Let it issue changed() notifications whenever something interesting happens.
Then let each SimScene wrap model into whatever QSceneItems it wants, and process changed() notifications.
Example:
Model:
Graph,
Edge,
Vertex
GUI
SimScene,
QEdge,
QVertex,
QSimInfo,
Qbackground, and so on ...
Also, you add pScene2 twice:
...
pView1->setScene(pScene2);
...
pView2->setScene(pScene2);
And allocate memory for the same pointer twice:
QGraphicsView* pView1 = new QGraphicsView();
...
QGraphicsView* pView1 = new QGraphicsView();