Using different Views with one model and different data

Wuzi

Sorry for my bad explanation.

Here is the main view.

This application should load Data files *.mf4 and store this data. The signals which are in this file are listen in the Listview "Signals". If you click on one of this signals, you will see a preview of this signal in the "Preview" Listview. The central Widget contains a tabwidget, where you can add charts. At the end you should be able to drag a Signal name in one of this charts, and the signal will be showed in this chart.

So I need the Signal name in the "Signals" Listview and the Signal data in the "Preview" and in the central widget charts.

SGaist

Ok, then isn't it rather a tree style model that you should have ?

Or if still a table style, you should maybe consider creating an object that encapsulates your signals data and build your model on top of that.

Wuzi

@SGaist said in Using different Views with one model and different data:

Ok, then isn't it rather a tree style model that you should have ?

You mean something like this:

Sounds good for me, thanks

@SGaist said in Using different Views with one model and different data:

Or if still a table style, you should maybe consider creating an object that encapsulates your signals data and build your model on top of that

You mean. creating for every signal a own model? Putting The signal names in a seperate model than the data?

Wuzi

No I created a tree model like in this example.

This is the code which add the data as SignalDataTreeItems to the m_root_item

    beginInsertRows(QModelIndex(), 0, channel_list.size()-1);

    for (int channel_index : channel_list) {
        const mdf::channel& ch = channels[channel_index];

        QList<QVariant> signalname = {QVariant::fromValue<QString>(QString::fromStdString(ch.get_name()))};
        SignalDataTreeItem *signal = new SignalDataTreeItem(signalname);

        QList<QVariant> unit_string = {QVariant::fromValue<QString>(QString::fromStdString(ch.get_metadata_unit()))};
        SignalDataTreeItem *unit = new SignalDataTreeItem(unit_string,signal);
        signal->appendChild(unit);


        // TODO: optimize this step!
        std::vector<double> column;
        ch.get_data_real(column);
        QList<QVariant> datas;
        foreach(double d, column){
            datas.append(QVariant(d));
        }
        SignalDataTreeItem *data = new SignalDataTreeItem(datas,signal);
        signal->appendChild(data);

        m_rootItem->appendChild(signal);
    }

    endInsertRows();

The problem is, that in the proxy the function data will never called.

SignalNamesProxyModel::SignalNamesProxyModel(QObject *parent): QSortFilterProxyModel (parent){
}

int SignalNamesProxyModel::rowCount(const QModelIndex &parent) const {
    int rowcount = sourceModel()->rowCount(QModelIndex()); // of root item (number of signals)
    return rowcount;
}

int SignalNamesProxyModel::columnCount(const QModelIndex &parent) const{
    return 1;
}

QVariant SignalNamesProxyModel::data(const QModelIndex &index, int role) const {

    QString value = sourceModel()->data(index).toString();

    return value;
}

QModelIndex SignalNamesProxyModel::index(int row, int column, const QModelIndex &parent)const {

    return sourceModel()->index(row,0,QModelIndex()); // child "row" of m_root_item of sourceModel (signal)
}

The problem is, that I don't understand how do I have to use beginInsertRows and endInsertRows, when I have to different datas, because the row count matches only for one view not for both at the same time.

SGaist

I just re-read your first post. In the end, can't it be simplified to a two column table ?

First column: name
Second column: data

Wuzi

@SGaist said in Using different Views with one model and different data:

I just re-read your first post. In the end, can't it be simplified to a two column table ?
First column: name
Second column: data

The problem is, that in the data variable are multiple signals:

row0, column0: signal0, first value
row0, column1: signal0, second value
row1, column0: signal1, first value
row1, colimn1: signal1, second value
....

So this is the second concept I tested while the weekend, it has nothing to do with the tree model.
I moved the signal name in a seperate listmodel (So it is easy to list all signal names in a list view).
The data I store in a table model.

The problem is, how can I set, which row of this table should be shown?
For example:
I have a chart where I would like to plot some of this data (but only few signals, not every row). I would like to select which signal should be used for the x axis and which should be used on the y axis. To do that I created a QSortFilterProxyModel and reimplemented the rowCount, columnCount and the mapToSource function as follows:

int SignalPreviewProxyModel::rowCount(const QModelIndex &parent) const {
    return 2*m_mapToSourceIndex.lenght();
}

int SignalPreviewProxyModel::columnCount(const QModelIndex &parent) const{

    int column = sourceModel()->columnCount(parent);
    return column;
}

QModelIndex SignalPreviewProxyModel::mapToSource(const QModelIndex & proxyIndex) const {

    if(!proxyIndex.isValid()){
        return QModelIndex();
    }

    int row = proxyIndex.row();
    int column = proxyIndex.column();

    int axis = row % 2; // modulo 2, because x and y axis
    int value = row /2; // graph

    if(axis == 0){
        row = m_mapToSourceIndex.at(value).first;
    }else{
        row = m_mapToSourceIndex.at(value).second;
    }
    QModelIndex index2 = sourceModel()->index(row,column,QModelIndex()); // get from already existing item the index
    return index2;
}

In this concept, the problem is, that mapToSource transformation is not invertable ( when there should be the possibility to display mutiple signals in the graph, this is why m_mapToSourceIndex is a vector of mappings), so I'm not able create the mapFromSource function and I get a segmentation fault.

I really don't know how I can solve this problem (which is the most common way?).
Thanks for helping me! :)

SGaist

I'm still wondering if there's not a bit of model over-engineering.

Wouldn't it be simpler to have a class that encapsulates a "signal". Store of all your signals in a QVector of that class.

Then build a simple table module that would return the data from the correct signal object.

struct Signal
{
    QString name;
    QString unit;
    QVector<QVariant> data;
};

class SignalTableModel
{

QVariant data(const QModelIndex &index, int role) const
{
    // Add index validity checks
    Signal signal(_signalVector.at(index.row()));
    if (index.column() == 1) {
        return signal.name();
    }
   // etc.
}

};

Wuzi

So you mean, when column ==1 then return name, when column == 2 then return unit and when the column is greater than 2 return the respective value?

So then I have to use a proxy between this model and the signal name list view and set the columcount to 1?

And for the chartview(derived from tableview) I have to use a proxy, which maps the index to +2 because the first two rows are name and unit?

Do I understand you correct?

SGaist

What do you mean by respective value ?

You can use a QListView so no need for fiddling with a proxy model.

And for the table view, you can simply hide the columns you don't want to show.

Wuzi

@SGaist said in Using different Views with one model and different data:

What do you mean by respective value ?
One signal consists of multiple data (due to a time range on which the signal was logged). The different signals are stored in a 2d array:

std::vector<std::vector<double> > m_data;

@SGaist said in Using different Views with one model and different data:

You can use a QListView so no need for fiddling with a proxy model.

Yes for the signal names I have a QListView. The signal names are stored in a list model. This works fine.

Or did I missunderstand your question?

SGaist

You wrote that you wanted to use a proxy and setting the columns count to 1 so I thought you were trying to "re-invent" QListView.

Wuzi

@SGaist said in Using different Views with one model and different data:

You wrote that you wanted to use a proxy and setting the columns count to 1 so I thought you were trying to "re-invent" QListView.

Oh sorry. this was in the concept with the tree model, but in the actual concept I have the data stored in a tablemodel.

SGaist

Ok, good.

So at what point are you now ?

Wuzi

@SGaist said in Using different Views with one model and different data:

Ok, good.
So at what point are you now ?

After reading you question I had a new idea (before I thought it is not possible to use KDChart to plot) :D :

a data class which stores all the data
a table model which stores a pointer to the data which I would like to display.
In this model I reimplement the data, rowcount and columncount function as following:

class Data
{
public:
   QVector<double>* getDataPointer(int index){return &m_data.at(index);}
private:
 QVector<QVector<double>> m_data;
};

// Every Diagram uses an object of this class
class SignalModel: public QAbstractTableModel
{
public:
- override rowcount
- override columncount
- override data
void addData(QVector<double>* xaxis, QVector<double>* yaxis);
private:
    QVector<QVector<double>*> m_data;
};

void SignalModel::addData(QVector<double>* xaxis, QVector<double>* yaxis){
// KDChart expects, that the axis keys and values are stored in different rows
m_data.append(xaxis);
m_data.append(yaxis);
}

int SignalModel::rowCount(const QModelIndex &parent) const {
  return m_data.lenght();
}

int SignalModel::columnCount(const QModelIndex &parent) const{

  int column = m_data.at(0)->length()
  return column;
}

QVariant SignalModel::data(const QModelIndex &index) const{

  return m_data.at(index.row)->at(index.column);
}

removeRow and insertRow must be reimplemented too, to add dynamically new data.

For showing the signal names I would reimplement a listmodel.

I think it is the simplest method to do my task. (If there are errors in my code, it is because I didn't tested it, it's just a sketch).
I found kst-plot which does exactly what I want. So I think it is easier to extend this program and help to contribute to this one, than rewriting a new one.

Thank you SGaist for your help and the inspiration. If this last concept is unclear, just write and I will extend it.