Insert fill circle into cell of QTableWidget



  • @SGaist

    I'm sorry, it was my vacation day and I wanted to move forward with the project. I'm sorry.

    To assign the matrix to the model simply the model creates a variable of the same type as the matrix and initialize the model I assign it in some way, is it correct? I do not understand the roles very well ...


  • Lifetime Qt Champion

    You should also provide APIs that will allow you ton modify that matrix.

    As for the roles, they are there to retrieve specific information from the model's elements.



  • @SGaist said in Insert fill circle into cell of QTableWidget:

    You should also provide APIs that will allow you ton modify that matrix.
    As for the roles, they are there to retrieve specific information from the model's elements.

    I'm sorry but I still do not understand well the models and roles in QT.
    Can anyone give me an example of how the model class should be?

    I have a matrix (vector <vector <Cell >>) and when modifying some attributes of the Cell class, have to change what is painted in the graphic representation (Only the one in the cell corresponding to the coordinates of the matrix).


  • Qt Champions 2017

    @juaniyoalm
    Hi
    Its something like this
    https://meetingcpp.com/blog/items/an-introduction-into-qt-part-3.html
    However he uses a
    std::vector<PersonalData> mydata;
    where you have
    vector <vector <Cell >>
    so you need to use both index.row and index.col
    to address your matrix. ( the data)



  • @mrjj Thanks so much.

    I was doing it that way, but how did I assign the matrix to the model variable? At this moment, I am creating the matrix in mainwindow class ...


  • Qt Champions 2017

    @juaniyoalm
    Hi
    well the vector <vector <Cell >> matrix could be inside the model
    and you would use method like the Addperson in sample to fill it.
    Much like you do now. when maxtrix is outside of the model.
    You could also fill it in mainwindow and simply give whole matrix to model
    to copy it to internal variable.(matrix) but thats a bit waste full.

    Also i been wanting to ask you. You do use a TableView because you need scrolling correct?
    I mean there are far more rows with cells than can fit on on screen ?



  • @mrjj

    Yes, there is no row limit, it can be 20 rows, 100 or 1000 xD. I always have to think about what I do to behave well when I do the parallel implementation, using pthread and openmp.


  • Qt Champions 2017

    @juaniyoalm
    Ok so scrolling is needed:)
    Also make sure to check out QtConcurrent and QThread before jumping to pthread.



  • @mrjj

    ok, I will look it.

    I have a doubt, when I modify a value of the Cell class (this is done in a method of the Cell class ), it will be modified automatically in the model or I have to do model-> setData (model-> index (i, j) , matrix [i] [j] -> getModifiedValue ())? The Cell of matrix are pointer...


  • Qt Champions 2017

    @juaniyoalm
    Well if you go with QAbstractTableModel
    your matrix IS the data so if you modify it
    and call dataChanged (model call ) to let view know data has been altered.



  • @mrjj

    ok, this is my model implementation:

    /#include "cellmodel.h"
    
    CellModel::CellModel(QObject *parent) : QAbstractTableModel(parent){}
    CellModel::CellModel(int rows, int columns, int fungivores)
    {
        this->mundo = new World(rows, columns, fungivores);
    }
    
    int CellModel::rowCount(const QModelIndex &parent) const
    {
        return this->mundo->world.size();
    }
    int CellModel::columnCount(const QModelIndex &parent) const
    {
        return this->mundo->world[0].size();
    }
    
    QVariant CellModel::data(const QModelIndex &index, int role) const
    {
        if(!index.isValid())
            return QVariant();
    
        if(index.row() >= mundo->world.size() || index.row() < 0 ||
               index.column() >= mundo->world[0].size() || index.column() < 0)
            return QVariant();
    
        if(role == Qt::DisplayRole || role == Qt::EditRole)
        {
            return this->mundo->world[index.row()][index.column()]->getFood();
        }
        return QVariant();
    }
    
    bool CellModel::setData(const QModelIndex &index, const QVariant &value, int role)
    {
        if (index.isValid() && role == Qt::EditRole && !(index.row() >= this->mundo->world.size() || index.row() < 0 ||
                                                         index.column() >= this->mundo->world[0].size() || index.column() < 0))
        {
            int row = index.row();
            int col = index.column();
    
            this->mundo->world[row][col]->setFood(value.toInt());
    
            emit dataChanged(index, index);
            return true;
        }
        return false;
    }
    
    Qt::ItemFlags CellModel::flags(const QModelIndex &index) const
    {
        if (!index.isValid())
            return Qt::ItemIsEnabled;
        return QAbstractTableModel::flags(index) | Qt::ItemIsEditable;
    }
    
    
    

    if I modify the value in this way: model-> world-> world [0] [0] -> setFood (200);

    1- All row is changed instead of just the selected cell.

    2 - Repaint all matrix, although the data of the others have not changed.


  • Qt Champions 2017

    hi
    If you place break point and check
    CellModel::data
    return this->mundo->world[index.row()][index.column()]->getFood();
    is row and index what you expect and does getFood() return different values?

    it looks ok.
    very much like
    http://doc.qt.io/qt-5/qtwidgets-itemviews-addressbook-tablemodel-cpp.html



  • @mrjj Hi!!

    In the variable index I get the whole world object (contains the matrix). Attached image:

    0_1543964832588_Selección_001.png

    I think the problem is in the setData method because if I delete the content of this method (I only leave the return false) the behavior does not change, that is, it continues to paint all row instead of just the one that has been modified.

    EDIT:

    When I modify the value with the setValue method of the Cell class, it does not pass through the setData method.


  • Qt Champions 2017

    @juaniyoalm
    Hi
    is index.row / col always 0,0 ?
    you can use QDebug to easy see it
    while running.



  • @mrjj

    No, is 0,0 because I have done it this way to test.


  • Qt Champions 2017

    @juaniyoalm
    ok, so it returns same data from any index() / cell ?



  • @mrjj

    No, each cell returns a different value, but in the modification of the UI it modifies all row with the value sent.

    EDIT:

    Is it normal that every time I touch the main window, the debug enters the data method of the model?


  • Qt Champions 2017

    @juaniyoalm
    Ok. Im not sure whats up.
    Maybe something with indexes().
    Cannot guess it.

    • the debug enters the data method of the model?
      Im not sure what it means ?


  • @mrjj

    I'm sorry, I wanted to say that, in the execution, when I touch the ui, the execution goes through the Data method and reviews all the indexes.

    Was there any way to send you to the app? It's a small app and I need to be able to move forward but I can not find the problem ......


  • Qt Champions 2017

    @juaniyoalm
    Hi
    You can link to dropbox or google drive. just zip project folder.



  • @mrjj

    This is the project:
    Project

    A short summary:

    At this time only the most basic is implemented.

    Cell Class: Contains an array of fungivores and an integer that represents the fungus. When the number of fungivores increases, the circle of the UI should become larger. When the amount of fungus increases or decreases, the color of the cell of the UI should change.

    Fungivore Class: At this moment it is only created so that it can be instantiated.

    World Class: Contains an array of fungivores (all fungivores of the app that will then be shared between the cells). In addition, it contains a Vector <Vector <Cell >> (Matrix).


  • Qt Champions 2017

    @juaniyoalm
    Hi
    some function was missing in NewDialog but i just made them return a valid value.
    You model actually seems fine (\o/)
    but i found out you would fill the whole
    row with same Cell , it seems.
    Doing this instead
    alt text

    and little change to Cell ( to to be able to see difference)

    Cell::Cell(QObject *parent) : QObject(parent)
    {
        this->fungus = 10 + (rand() % 5);
    }
    
    

    It now seems to edit fine :)



  • @mrjj Thank you so much!!

    But if you modify a cell with the setfood method, does it modify it well?


  • Qt Champions 2017

    @juaniyoalm
    Hi
    You mean via

    void MainWindow::changeVal()
    {
        model->mundo->world[0][0]->setFood(200);
    }
    
    

    Yes it does, but you first see it if u click in cell as you secretly change it directly in list
    and the model dont know.

    so do like this
    model->setData(model->index(2,2),200,Qt::EditRole);
    and it refesh it self.

    alt text



  • @mrjj

    Thanks so much!!

    The problem was in World constructor , as you said.

    once solved this problem, as you will have noticed, I only change the color of the cell, and I also need to change the size of the circle, according to the number of fungivores that there are. How can I pass this data to the model, or to differentiate what data is happening to it?

    EDIT:

    Another problem is that if I modify the values in a loop, for example:

        int count = 0;
        while (count < 3000) {
            for(int i = 0; i < this->rows; i++) {
                for(int j = 0; j < this->col; j++) {
                    model->mundo->world[i][j]->setFood(rand() % 255);
                    //model->setData(model->index(i,j),200,Qt::EditRole);
                    qDebug("El ModelIndex[%i][%i] lleva los datos: %i", i, j, model->mundo->world[i][j]->getFood());
                }
            }
    
            count++;
        }
    

    The UI is not updated until the loop completes. It may be that the loop strangles the events ... that's a big problem for me.


  • Qt Champions 2017

    @juaniyoalm said in Insert fill circle into cell of QTableWidget:

    How can I pass this data to the model, or to differentiate what data is happening to it?

    But the model has already access to the Cell structure. ( via model)
    So delegate can read the information and calculate the size of circle with more.

    Regarding the loop.
    Yes, i think the loop will strangle the event loop as 3000 x row x col might take some time.
    One option is to use QCoreApplication::processEvents in the loop but thats not so pretty.
    It would be better to use a timer to change the food over time and keep the UI responsive.



  • @mrjj

    But the delegate receives the data of the model and this only has the value of the food (color).

    Regarding the timer. I need not delay the execution time, because later I must see the difference between parallel version of the app and this version.


  • Lifetime Qt Champion

    As long as your model stores all the data you need, your delegate can access them. Use custom roles for these additional informations. This has the added advantage to make your code easier to read and understand.



  • @mrjj @SGaist Hi!!

    If I put QCoreApplication::processEvents(); the UI is not updated until, for example, I do not select the cells in the UI. I need them to be updated automatically when I change the values from a method of the world class. I can not use timer and the values change each time range because this application will later have a parallel version and what is searched in that app is the simulation of a real biological environment as quickly as possible. I need a solution, because I'm delaying too much at the point of the UI (it's the least important).

    I want to thank you for all the help you have given me, but I need to solve this point.

    The method that will modify the values is not this, but it will look like this:

    void World::initializeWorld() {
    
        int count = 0;
    
        while (count < 1500) {
            for(int i = 0; i < rowSize(); i++) {
                for(int j = 0; j < rowSize(); j++) {
                    getCell(i,j)->setFood(rand()&255);
                }
            }
            count++;
             QCoreApplication::processEvents();
        }
    }
    

    I put the updated project link in case you want to look at it:

    Update Project


  • Qt Champions 2017

    @juaniyoalm
    Hi
    The timer is meant as a way of not strangulating the event loop.
    its not as fast a tight loop as it goes over the event loop but it
    allows redraw of the view. ( which also uses the event loop to actually redraw)
    Anyway, you are looping row x colSize ( actually rox x row ??)
    and then allow event loop.
    maybe you mean like this ?

     while (count < 1500) {
            for(int i = 0; i < rowSize(); i++) {
                for(int j = 0; j < rowSize(); j++) { // should this not be colSize ?
                    getCell(i,j)->setFood(rand()&255);
                   QCoreApplication::processEvents();
                }
            }
            count++;
          
        }
    


  • @mrjj said in Insert fill circle into cell of QTableWidget:

    QCoreApplication::processEvents();

    Row x Row is because the rows will really be the same as the columns.

    I have also tried to locate QCoreApplication :: processEvents (); in that position, with the same effect, that is, it does not update well in the UI.

    If the timer does not penalize the execution time of the program and only acts in the reprssentación of the UI, it could be good. How should I do it?


  • Qt Champions 2017

    Hi

    • it does not update well in the UI.

    meaning it does update sometimes or what result do you get ?

    here is sample of changing random cell

    int random(int min, int max) //range : [min, max)
    {
        static bool first = true;
        if (first) {
            srand( time(nullptr) ); //seeding for the first time only!
            first = false;
        }
        return min + rand() % (( max + 1 ) - min);
    }
    
    void MainWindow::changeVal()
    {
        //model->mundo->world[4][4]->setFood(200);
        auto timer = new QTimer(this);
        QObject::connect(timer, &QTimer::timeout, [this]() {
            int rowCount = this->model->rowCount(QModelIndex());
            int colCount = this->model->columnCount(QModelIndex());
            this->model->setData(model->index(random(0, rowCount), random(0, colCount)), random(0, 20), Qt::EditRole);
        });
        timer->start(10);
    
    }
    Note that sample will create a timer each time you select Change val menu so
    its better to move timer as member. 
    Also it uses a lambda as slot. you can use a normal slot for it and let it be part of World class.
    
    • If the timer does not penalize the execution time of the program
      it does to some degree. But even using Threads, you will have to ask it to update and redraw
      over the event loop as the VIEW cannot update if you strangulate it using tight loops.

    But using timer is not super slow.
    alt text
    (video is actually slower than real deal)



  • @mrjj

    meaning it does update sometimes or what result do you get ?

    Means that the UI is only updated if I interact with it, that is, if for example I select the cells, then it shows the changes made in the code.

    But using timer is not super slow

    Yes but in the parallel version it should go faster and if I use a timer, it will always take the same time, because the time depends on the timer variable.

    Video with an example of what happens to me:

    Video

    Change button calls the InitializeWorld() method.


  • Qt Champions 2017

    @juaniyoalm said in Insert fill circle into cell of QTableWidget:

    • it will always take the same time, because the time depends on the timer variable.

    Not really. the timer will call your function at a fix time. Your function will take the time it takes but using a timer, its all driven like a loop but allows the event to run to the view can update.

    Anyway, what you are seeing is expected.
    You are modifying the vector list BEHIND models back. It dont know you changed some of its data so first when you click something, view re-reads the cells and draws the values.

    Recall the setData.

    bool CellModel::setData(const QModelIndex &index, const QVariant &value, int role)
    {
        auto RowCount = this->mundo->world.size();
        auto ColCount = this->mundo->world[0].size();
        qDebug () << "role=" << role;
        if (index.isValid()            
                && role == Qt::EditRole
                && index.row() < RowCount
                && index.row() >= 0
                && index.column() <  ColCount
                && index.column() >= 0
           ) {
            int row = index.row();
            int col = index.column();
    
            this->mundo->world[row][col]->setFood(value.toInt());
    
            emit dataChanged(index, index);
            return true;
        }
        return false;
    }
    

    here we emit dataChanged so view knows something changed.
    when you do
    getCell(i,j)->setFood(rand()&255);
    you are not telling model/view you changed the list and that is why
    QCoreApplication::processEvents(); do not help.



  • But if you modified only the value of a cell if work fine.

    How could I then modify the value? It has to be modified from the world class. Could I put a signal when modified with the setdata method?


  • Qt Champions 2017

    @juaniyoalm
    Hi
    You can add add signal to World class and connect it to the model. and then emit it
    to have model call DataChanged. OR give World a pointer to the model and use models
    API to change data and inform view.

    • But if you modified only the value of a cell if work fine.
      im not sure what u say here.


  • @mrjj
    I want to say that if I do this

    getCell(0,0)->setFood(rand()&255);
         
    

    The UI update fine and model unknown data either


  • Qt Champions 2017

    @juaniyoalm
    Ok. not really sure how,
    but didnt check the latest version.
    Also if the VIEW get an update/paintEvent it will re-read the indexes so i guess
    its via the normal paint/update/redraw.



  • @mrjj

    I have already solved the problem. I have created a signal in the Cell class that is emited when the value of the cell is modified. This signal sends the cell to the slots. Then I created a slot in the MainView class and connected each cell of the model's matrix with that slot. This slot creates a QModelIndex and issues a dataChanged for the model to update the view. Besides, I had to save the position of the cell in the cell class.

    Emit Signal:

    void Cell::setFood(int food)
    {
        if(this->fungus != food) {
            this->fungus = food;
            emit this->updateModel(this);
        }
    }
    

    Slot:

    void MainWindow::foodChanged(Cell *cell)
    {
        QModelIndex aux = model->index(cell->place.first, cell->place.second);
        model->dataChanged(aux, aux);
    }
    

    Connections:

        for (int i = 0; i < this->rows; i++) {
            for (int j = 0; j < this->columns; j++) {
                connect(this->model->mundo->getCell(i, j), &Cell::updateModel, this, &MainWindow::foodChanged);
            }
        }
    

    Now I need pass the value of the circle also in the data method so that the delegate's paint method can receive it ...
    Any example of how to do it?


  • Lifetime Qt Champion

    As I already suggested many times: use custom roles. So in your paint function, request the data using the roles specific to the parameters you want to get.


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