Get index of the clicked element in QML GridView

MoaMoaK

Hi everyone,
I've a class (PLModel) subclassing QAbstractItemModel and passed to a QML GridView through context. The display works fine. Now i want to invoke a custom method in my PLModel when an element is clicked on. Here is the code i've come up with :

plmodel.hpp (simplified)

class PLModel : public QAbstractItemModel
{
    Q_OBJECT

public : 
    // Constructor
    PLModel()

    // Subclassing QAbstractItemModel
    QVariant data( const QModelIndex &index, const int role ) const Q_DECL_OVERRIDE;
    bool setData( const QModelIndex &index, const QVariant & value, int role = Qt::EditRole ) Q_DECL_OVERRIDE;
    int rowCount( const QModelIndex &parent = QModelIndex() ) const Q_DECL_OVERRIDE;
    Qt::ItemFlags flags( const QModelIndex &index ) const Q_DECL_OVERRIDE;
    QModelIndex index( const int r, const int c, const QModelIndex &parent ) const Q_DECL_OVERRIDE;
    QModelIndex parent( const QModelIndex &index ) const Q_DECL_OVERRIDE;

    //The function i want to invoke
    Q_INVOKABLE virtual void activateItem( const QModelIndex &index ) Q_DECL_OVERRIDE;

    // Irrelevant stuff
    ...

};

plmodel.cpp (simplified)

// Constructor
PLModel::PLModel() { }

// Subclassing QAbstractItemModel
QVariant PLModel::data( const QModelIndex &index, const int role ) const { ... }
bool PLModel::setData( const QModelIndex &index, const QVariant & value, int role ) { ... }
int PLModel::rowCount( const QModelIndex &parent ) const { ... }
Qt::ItemFlags PLModel::flags( const QModelIndex &index ) const { ... }
QModelIndex PLModel::index( const int row, const int column, const QModelIndex &parent ) { ... }
QModelIndex PLModel::parent( const QModelIndex &index ) const { ... }

// The function I want to invoke
void PLModel::activateItem( const QModelIndex &index )
{
    // Print content for debug
    log_info ( index.row() )
    log_info ( index.column() )

    // Do some stuff about this specific item
    ....
}

ui.qml

import QtQuick 2.0
Item {
    width: 1000
    height: 1000

    GridView {
        id: gridView
        anchors.fill: parent
        cellWidth: 150
        cellHeight: 150
        model: m     //The model passed through context
        delegate: Item {
            x: 5
            height: 50
            
            Image {
                anchors.horizontalCenter: parent.horizontalCenter
                id: image
                width: 100
                height: 100
                source: model.image
                MouseArea {
                    anchors.fill: image
                    /* Where i invoke the method */
                    onClicked: m.activateItem(index)
                }
            }
        }
    }
}

So my problem is that everytime i clicked on an item in the UI (no matter which one), the index has row=-1 and column=-1 so i don't know in the C++ code which item was clicked. I don't understand why. Am i doing something wrong ? Or is there another way to do what i want to do ?

Thx

sierdzio

index attached role is not a QModelIndex - it is an integer. That is because QML does not support table data. More info here.

So you can either calculate the correct item from index (based on amount of columns you have), or provide a model role and then react to that in setData(). For example:

// QML
MouseArea {
  onClicked: myCustomRole = 1
}

// C++
setData()
{
  if (role == myCustomRole) {
    // ignore the QVariant value, it is irrelevant in this case
    activateItem(index);
  }
}

MoaMoaK

Ok thx that works like a charm. Both solutions.