So it's built into the Qt base library then.

I noticed also that any time the table gets clicked that method must get called again because I get another complete set of qDebug() messages. So paint() makes sense then as to why that happens.

Thanks

@tskardal said in How do you persist and update your models?:

I'm thinking that the goal is having "plain" models that are not QObjects.

That's a quite normal thing to do. Let the Qt model be just an intermediary between actual data model/tree and the GUI.

If your implementation works, then it's OK I guess. I'm not sure if there any actual question to answer here :-)

I'm doing something similar in sort of objects property tree. It works pretty well for large number of items. Definitely a massive win over a widget per item approach.
One difference to your approach is that I don't use grab(), but instead have the editors created by the delegate a static drawing function that uses QStyle::drawControl and friends to draw an image of itself. This is because I don't want to instantiate all the editor widgets upfront to grab them (I have a bunch of them and it takes time). It's sort of a trade-off because it can get out of sync with the actual widget look. Whether this is something you'd be interested in or not is up to you, but the general idea of drawing an image is a valid one.

Interestingly, if I make the plugin static, it works fine. Only when the plugin is dynamic does this error happen... Very strange.

This subject is rather old but I also have not found any example and I took time to make it work.
Below my proposal
Click on the chart to randomly append data

main.cpp

#include <QQmlEngine> #include <QApplication> #include <QQmlApplicationEngine> #include "chartmodel.h" int main(int argc, char *argv[]) { #if defined(Q_OS_WIN) QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling); #endif QApplication app(argc, argv); //Use QApplication for QChart, QGuiApplication causes a bug qmlRegisterType<ChartModel> ("MainLib", 1, 0, "ChartModel"); QQmlApplicationEngine engine; engine.load(QUrl(QStringLiteral("qrc:/main.qml"))); if (engine.rootObjects().isEmpty()) return -1; return app.exec(); }

chartmodel.h

#ifndef CHARTMODEL_H #define CHARTMODEL_H #include <QVector> #include <QAbstractTableModel> //#include <QDebug> class ChartModel : public QAbstractTableModel { Q_OBJECT QVector<QPair<double,double>> vec_; double m_xMin; double m_xMax; double m_yMin; double m_yMax; Q_PROPERTY (double xMin READ get_xMin WRITE set_xMin NOTIFY xMinChanged) Q_PROPERTY (double xMax READ get_xMax WRITE set_xMax NOTIFY xMaxChanged) Q_PROPERTY (double yMin READ get_yMin WRITE set_yMin NOTIFY yMinChanged) Q_PROPERTY (double yMax READ get_yMax WRITE set_yMax NOTIFY yMaxChanged) public: explicit ChartModel(QObject *parent = nullptr); int rowCount(const QModelIndex &parent = QModelIndex()) const override; int columnCount(const QModelIndex &parent = QModelIndex()) const override; QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override; // QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override; double get_xMin() const; double get_xMax() const; double get_yMin() const; double get_yMax() const; public slots: bool set_xMin(double val); bool set_xMax(double val); bool set_yMin(double val); bool set_yMax(double val); void appendData(); signals: void xMinChanged(double); void xMaxChanged(double); void yMinChanged(double); void yMaxChanged(double); }; #endif // CHARTMODEL_H

chartmodel.cpp

#include "chartmodel.h" ChartModel::ChartModel(QObject *parent) : QAbstractTableModel(parent) { m_xMin = 0.; m_xMax = 1.; m_yMin = 0.; m_yMax = 1.; } int ChartModel::rowCount(const QModelIndex & /* parent */) const { return vec_.size(); } int ChartModel::columnCount(const QModelIndex & /* parent */) const { return 2; } QVariant ChartModel::data(const QModelIndex &index, int role) const { if (!index.isValid() || role != Qt::DisplayRole) return QVariant(); if (index.column() == 0){ return vec_.at(index.row()).first; } if (index.column() == 1){ return vec_.at(index.row()).second; } return QVariant(); } double ChartModel::get_xMin() const { return m_xMin; } double ChartModel::get_xMax() const { return m_xMax; } double ChartModel::get_yMin() const { return m_yMin; } double ChartModel::get_yMax() const { return m_yMax; } bool ChartModel::set_xMin(double val) { bool ret = false; if ((ret = (m_xMin != val))) { m_xMin = val; emit xMinChanged (m_xMin); } return ret; } bool ChartModel::set_xMax(double val) { bool ret = false; if ((ret = (m_xMax != val))) { m_xMax = val; emit xMaxChanged (m_xMax); } return ret; } bool ChartModel::set_yMin(double val) { bool ret = false; if ((ret = (m_yMin != val))) { m_yMin = val; emit yMinChanged (m_yMin); } return ret; } bool ChartModel::set_yMax(double val) { bool ret = false; if ((ret = (m_yMax != val))) { m_yMax = val; emit yMaxChanged (m_yMax); } return ret; } void ChartModel::appendData() { int const nbData = 1+qRound(10.*double(qrand())/double(RAND_MAX)); int const vecSize = vec_.size(); if (!vecSize){ m_xMin = qInf(); m_xMax = -qInf(); m_yMin = qInf(); m_yMax = -qInf(); } beginInsertRows(QModelIndex (), vecSize, vecSize+nbData); for(int seed = 0 ; seed < nbData; ++seed){ double const xVal = vec_.size(); double const yVal = double(qrand())/double(RAND_MAX); set_xMin(qMin(m_xMin, xVal)); set_xMax(qMax(m_xMax, xVal)); set_yMin(qMin(m_yMin, yVal)); set_yMax(qMax(m_yMax, yVal)); vec_.append(qMakePair<double, double>(xVal, yVal)); } endInsertRows(); }

main.qml

import QtQuick 2.10 import QtQuick.Window 2.10 import QtCharts 2.0 import MainLib 1.0 Window { visible: true width: 640 height: 480 title: qsTr("Hello World") property ChartModel chartModel : ChartModel{} ChartView { id : chart anchors.fill: parent antialiasing: true animationOptions: ChartView.AllAnimations SplineSeries { id : serie1 axisX : ValueAxis { id: xAxis min: chartModel.xMin max: chartModel.xMax } axisY : ValueAxis { id: yAxis min: chartModel.yMin max: chartModel.yMax } VXYModelMapper { id: mapper xColumn: 0 yColumn: 1 model: chartModel } } MouseArea{ anchors.fill : parent onClicked: { chartModel.appendData() } } } }

Hi! Just to be sure I understood this correctly: You have a single DB with a humongous number of identically structured tables? Do you really believe you can store 2^128 bits / rows / tables / whatever in your database / filesystem / datacenter?

In worst case I will have to keep in RAM about 4e+38 of 16 bytes pointers

Even that is way more rows than what a SQLite table can hold (see: https://www.sqlite.org/limits.html).

I had create a model with key and value and pass it to qml, it worked!!!
Sorry for late reply.
Thank you @raven-worx

The easy way:
get rid of PortalMapItemInfo, store the values in 4 different QStringList and use a QStringListModel

The proper way:
in HomeController.h add Q_DECLARE_METATYPE(PortalMapItemInfo) http://doc.qt.io/qt-5/qmetatype.html#Q_DECLARE_METATYPE

Instead of a List store your data in a 1-column QStandardItemModel and expose it via a Q_PRPERTY

@Mathan-M Why do you want to bind to ListElement?
ListElement's are added to ListModel.
You should probably try to access this model from C++. ListModel is also a QAbstractItemModel.

@VRonin said in Smarter way to get a list of children in Tree Model:

the overridden data is to store somewhere the level in the original tree before it gets flattened by KDescendantsProxyModel.

I don't believe you need that. Pushing a tree model to a list/table view should give you list/table with the root-level items (speculation again!). In my mind it should be just enough to "move" the root of the model before giving it to the view.

I didn't feel like going through building a QAbstractProxyModel from scratch

Well, yes, I can see why, but if you think about it, most of your methods should turn out trivial (more or less) - similarly to the identity proxy model.

Kind regards.

Yeah but the user also want to be able to reorder things as he wants, not just sort (ie, put this row here, drag all my selection at this position, invert these two rows, ...)

Ok. Thank you for your answer.
I never use QAbstractListModel. Do you have some keys to start ?

What is difference between using QAbstractListModel and QQmlListProperty ?
In which case is it better to use them ?

That's a brilliant and elegant solution!
Thank you bro for spending your precious time with a newbie like me!

@p3c0 said:

@Kofr So is it that you want to access the roles (namely hue, saturation, brightness) values from outside of this ListView delegate ? If so then did you accessing ListVIew model from outside ? Once you get hold of it the data can be accessed too.

code above is just example, not my case. what I need is to get model.roleName of delegate j when I work in delegate i

@Mark81 Even in JavaScript you have two models, you just don't typically think of it that way: model 1: the database, model 2: the results on the client side.

Here, you have two models: 1 - the database, 2 - the QML side.

So what you need to do is create a paginated model using LIMIT/OFFSET queries.

@Mark81 If index is 0 then don't start the animation. Well something like:

property int myIndex : 0 function animate(idx) { listAnimation.running = false var pos = list.contentY; var destPos; list.positionViewAtIndex(idx, ListView.Beginning); destPos = list.contentY; listAnimation.from = pos; listAnimation.to = destPos; listAnimation.running = true; } Timer { ... onTriggered: { if(myIndex==0) list.positionViewAtIndex(myIndex,ListView.Beginning); else animate(myIndex) myIndex++ if(myIndex==list.count-1) myIndex = 0 } }

@Qmyo You can create a 2 Q_INVOKABLE functions. One will return the Repeater's model number and other will return ListView's models. You can make use of index attached property which can be passed to the Q_INVOKABLE functions to return particular model.

In dropEvent called a new function from model which stores all the parameter of item when droped and emitted layoutAboutToBeChanged() before appending to my TableList and then emitted layoutChanged() which worked for me.

Thanks to @kshegunov , @SGaist , @mrjj for the help.

Sneaky one !

Glad you found out :)

@SGaist I don't mind refactoring it, it's not very long. I will definitely look into this. Thanks!

Thanks for your efforts.
As you said it works in a project I have a second look at my code.
I'm not writing a Quick-App but a QWidget-App and use the map inside a QQuickWidget. I have read about another approach to embed qml content in a QWidget-App using QQuickView inside a QObject-Container.
This approach works as expected. I don't know why it doesn't work with a QQuickWidget but my problem is solved.

Best Regards

Code would help.
And do you see any error messages when your app crashes? Did you try to debug?

@Alexander_Lanin didn't see you already found it before I submit my reply...

Thanks for reply. I already solved it too.

It's necessary to return pointer to AnimalModel and not reference. Also there is no necessity for NOTIFY.

So this is the correct way:

Q_PROPERTY(AnimalModel * modelAnimals READ modelAnimals CONSTANT) AnimalModel* modelAnimals() { return &m_model;}

Hi and welcome to devnet,

To make models accessible to QML you have to do sum customization like described in the QtQuick Model Views Data documentation.

QSqlTableModel example here

Good !

Since you have it working now, please mark the thread as solved using the "Topic Tool" button so that other forum users may know a solution has been found :)

You're setting the wrong role. See my answer here.

@mrjj

ROFL! The function call was before setupUI ^.^ I'll see if that fixes it :P

Edit: Yep! That was the problem :P My bad! Thanks for the help!

@renatobibiano Ok. Try giving width and height explicitly for components where you have used anchors.fill: parent.

@Chris-Kawa thanks, i now see the thing.
I've found example http://doc.qt.io/qt-5/modelview.html#2-5-the-minimal-editing-example but it use QAbstractTableModel and i'm using a QSqlRelationalTableModel instead of QSqlTableModel.

Will it still works for relations ? I can't found an Abstract for RelationalTableModel.

I have solved my problem in this way:

First I have changed the modelColumn to the Column with the key-value in the second combobox:

ui->cbCostCenterGr->setModelColumn(0);

Then I fetch the key-value for the second combobox from the first combobox...

QModelIndex id = ui->cbCostCenter->model()->index(index, 2); QString _CcGr = id.data().toString();

...and search the value in the second combobox:

ui->cbCostCenterGr->setCurrentIndex(ui->cbCostCenterGr->findText(_CcGr));

At least I change the modelColumn of the second combobox to the column with the text (to display the text and not the key-value):

ui->cbCostCenterGr->setModelColumn(1);

Here is the hole function:

void VoucherPosForm::on_cbCostCenter_activated(int index) { ui->cbCostCenterGr->setModelColumn(0); QModelIndex id = ui->cbCostCenter->model()->index(index, 2);//"2" is the key-column QString _CcGr = id.data().toString(); ui->cbCostCenterGr->setCurrentIndex(ui->cbCostCenterGr->findText(_CcGr)); ui->cbCostCenterGr->setModelColumn(1); }

It works fine, but is there a straighter way??

Thanks. It worked

@p3c0 This sounds like a very easy solution, I'll try it out. Thank you.