Edit QStandardItemModel via TableView with Custom Delegate - c++

Question

I have a QStandardItemModel which I display via a QML Table view.
Here is the model:
class mystandardmodel: public QStandardItemModel
{
public:
mystandardmodel();
enum Role {
role1=Qt::UserRole,
role2
};
explicit mystandardmodel(QObject * parent = 0): QStandardItemModel(parent){}
//explicit mystandardmodel( int rows, int columns, QObject * parent = 0 )
// : QStandardItemModel(rows, columns, parent){}
QHash<int, QByteArray> roleNames() const{
QHash<int, QByteArray> roles;
roles[role1] = "one";
roles[role2] = "two";
return roles;
}
};
and this is how the model is displayed using custom delegates:
TableView {
id: tableView2
x: 69
y: 316
width: 318
height: 150
TableViewColumn {
title: "Parameter Name"
role: "one"
}
TableViewColumn {
title: "Value"
role: "two"
delegate: myDelegate
}
model: myTestModel
}
Component {
id: myDelegate
Loader {
property var roleTwo: model.two
sourceComponent: if(typeof(roleTwo)=='boolean') {
checkBoxDelegate}
else { stringDelegate}
}
}
Component {
id: checkBoxDelegate
CheckBox{text: roleTwo}
}
Component {
id: stringDelegate
TextEdit {text: roleTwo}
}
I populated the model like this:
mystandardmodel* mysmodel=new mystandardmodel(0);
QStandardItem* it = new QStandardItem();
it->setData("data1", mystandardmodel::role1);
it->setData(true, mystandardmodel::role2);
it->setCheckable(true);
it->setEditable(true);
mysmodel->appendRow(it);
QStandardItem* it2 = new QStandardItem();
it2->setData("data2",mystandardmodel::role1);
it2->setData("teststring",mystandardmodel::role2);
mysmodel->appendRow(it2);
How can I make the model editable, so that using the checkBox or editing the text is transfered back to the model?
Edit: I tried to follow the suggestion in In QML TableView when clicked edit a data (like excel) and use set model:
Component {
id: myDelegate
Loader {
property var roleTwo: model.two
property int thisIndex: model.index
sourceComponent: if(typeof(roleTwo)=='boolean') {
checkBoxDelegate}
else { stringDelegate}
}
}
Component {
id: checkBoxDelegate
CheckBox{text: roleTwo
onCheckedChanged: {
myTestModel.setData(0,"two",false)
console.log('called',thisIndex)
}
}
}
Component {
id: stringDelegate
TextEdit {text: roleTwo
onEditingFinished: {
myTestModel.setData(thisIndex,"two",text)
console.log('called',thisIndex)
}
}
}
The index is OK, but it seems that it does not have an effect (I added a second TableView with the same model, but the data there does not get updated if I edit it in the first TableView)

Answer 1

You can directly set a value to model.two and that will automatically call setData with the correct role and index:
import QtQuick 2.10
import QtQuick.Controls 2.0 as QQC2
import QtQuick.Controls 1.4 as QQC1
import QtQuick.Layouts 1.3
QQC2.ApplicationWindow {
visible: true
width: 640
height: 480
ColumnLayout {
anchors.fill: parent
Repeater {
model: 2
QQC1.TableView {
Layout.fillWidth: true
Layout.fillHeight: true
QQC1.TableViewColumn {
title: "Parameter Name"
role: "one"
}
QQC1.TableViewColumn {
title: "Value"
role: "two"
delegate: Loader {
property var modelTwo: model.two
sourceComponent: typeof(model.two) ==='boolean' ? checkBoxDelegate : stringDelegate
function updateValue(value) {
model.two = value;
}
}
}
model: myModel
}
}
}
Component {
id: checkBoxDelegate
QQC1.CheckBox {
text: modelTwo
checked: modelTwo
onCheckedChanged: {
updateValue(checked);
checked = Qt.binding(function () { return modelTwo; }); // this is needed only in QQC1 to reenable the binding
}
}
}
Component {
id: stringDelegate
TextEdit {
text: modelTwo
onTextChanged: updateValue(text)
}
}
}
And if that's still too verbose and not enough declarative for you (it is for me), you can use something like the following, where most of the logic is in the Loader and the specifics delegates just inform what is the property where the value should be set and updated from :
delegate: Loader {
id: loader
sourceComponent: typeof(model.two) ==='boolean' ? checkBoxDelegate : stringDelegate
Binding {
target: loader.item
property: "editProperty"
value: model.two
}
Connections {
target: loader.item
onEditPropertyChanged: model.two = loader.item.editProperty
}
}
//...
Component {
id: checkBoxDelegate
QQC1.CheckBox {
id: checkbox
property alias editProperty: checkbox.checked
text: checked
}
}
Component {
id: stringDelegate
TextEdit {
id: textEdit
property alias editProperty: textEdit.finishedText // you can even use a custom property
property string finishedText
text: finishedText
onEditingFinished: finishedText = text
}
}

Answer 2

Using setData() could be an option, but it requires an integer value that indicates the role that is not accessible in QML, or rather is not elegant.
A better option is to create a new one that is Q_INVOKABLE. As the update is given in the view it is not necessary to notify it besides causing strange events.
to obtain the row we use the geometry and the rowAt() method of TableView.
The following is an example:
main.cpp
#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQmlContext>
#include <QStandardItemModel>
class MyStandardModel: public QStandardItemModel
{
Q_OBJECT
public:
enum Role {
role1=Qt::UserRole+1,
role2
};
using QStandardItemModel::QStandardItemModel;
QHash<int, QByteArray> roleNames() const{
QHash<int, QByteArray> roles;
roles[role1] = "one";
roles[role2] = "two";
return roles;
}
Q_INVOKABLE void updateValue(int row, QVariant value, const QString &roleName){
int role = roleNames().key(roleName.toUtf8());
QStandardItem *it = item(row);
if(it){
blockSignals(true);
it->setData(value, role);
Q_ASSERT(it->data(role)==value);
blockSignals(false);
}
}
};
int main(int argc, char *argv[])
{
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
QGuiApplication app(argc, argv);
MyStandardModel model;
for(int i=0; i< 10; i++){
auto item = new QStandardItem;
item->setData(QString("data1 %1").arg(i), MyStandardModel::role1);
if(i%2 == 0)
item->setData(true, MyStandardModel::role2);
else {
item->setData(QString("data2 %1").arg(i), MyStandardModel::role2);
}
model.appendRow(item);
}
QQmlApplicationEngine engine;
engine.rootContext()->setContextProperty("myTestModel", &model);
engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
if (engine.rootObjects().isEmpty())
return -1;
return app.exec();
}
#include "main.moc"
main.qml
import QtQuick 2.9
import QtQuick.Window 2.2
import QtQuick.Controls 1.4
Window {
visible: true
width: 640
height: 480
title: qsTr("Hello World")
TableView {
id: tableView2
anchors.fill: parent
TableViewColumn {
title: "Parameter Name"
role: "one"
}
TableViewColumn {
title: "Value"
role: "two"
delegate: myDelegate
}
model: myTestModel
}
Component {
id: myDelegate
Loader {
property var roleTwo: model.two
sourceComponent: typeof(roleTwo)=='boolean'? checkBoxDelegate: stringDelegate
}
}
Component {
id: checkBoxDelegate
CheckBox{
checked: roleTwo
onCheckedChanged:{
var pos = mapToGlobal(0, 0)
var p = tableView2.mapFromGlobal(pos.x, pos.y)
var row = tableView2.rowAt(p.x, p.y)
if(row >= 0)
myTestModel.updateValue(tableView2.row, checked, "two")
}
}
}
Component {
id: stringDelegate
TextField {
text: roleTwo
onEditingFinished: {
var pos = mapToGlobal(0, 0)
var p = tableView2.mapFromGlobal(pos.x, pos.y)
var row = tableView2.rowAt(p.x, p.y)
if(row >= 0)
myTestModel.updateValue(tableView2.row, text, "two")
}
}
}
}
The complete example can be found in the following link.