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Data not displaying on the QTreeView, QTableView,QListView classes

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  • JonBJ JonB

    @VRonin
    That's why I said "might get away with". I know how fond you C++ people here are about using the stack instead of the heap if at all possible (whereas I am Python/PyQt and so just use the heap the whole time :) ), so I put that in in case someone complained, I did wonder about it. I'll just cross it through!

    T Offline
    T Offline
    thippu
    wrote on last edited by
    #7

    @JonB , @VRonin I want to learn model/view architecture, so I picked up the Book Qt 4 art of building to study and practice, went to 207 page for basic understanding and page 222 example I want to study and implement,

    1. They have told to store the .csv file format like this :
      ’’title (column 1)’’, ’’title (column 2)’’, ...,’’title (column n)’’
      ’’value’’, ’’value’’, ..., ’’value’’
      ’’value’’, ’’value’’, ..., ’’value’’
      ’’value’’, ’’value’’, ..., ’’value’’
      if I store like this and do qDebug() on the QList object, which has all the values of lines, it is giving output "" "" so, I did change the format and stored like this with values :
      csv file:
      'Name', 'Address'
      'thippu', 'talacaverlayout'
      after this change, qDebug() did show file data.
    2. output and Ui
      2)Not understanding why the data is not displaying on the Views.
      code AddressbookGui:
    //csv file read method.
    QStringList splitCSVLine(const QString& line)
    {
    bool inItem = false;
    QStringList items;
    QString item;
    for (int pos = 0; pos < line.length(); pos++)
    {
    QChar c=line.at(pos);
    if ( c == ’\’’) {
    if (inItem) {
    items.append(item);
    item = "";
    }
    inItem = !inItem;
    }
    else
    if (inItem) {
    item += c;
    }
    }
    return items;
    }
    
    //constructor
    AddressbookModel::AddressbookModel(const QString& addresses,
    QObject *parent): QAbstractTableModel(parent)
    {
    QStringList records = addresses.split(’\n’);
    QStringList line;
    foreach(QString record, records)
    addressBook.append(splitCSVLine(record));
    }
    
    
    int AddressbookModel::rowCount(const QModelIndex &parent ) const
    {
    Q_UNUSED(parent);
    return addressBook.count() - 2;
    }
    
    
    //rowCount method
    int AddressbookModel::columnCount(const QModelIndex &parent ) const
    {
    Q_UNUSED(parent);
    return addressBook.at(0).count();
    }
    
    //headerData method
    QVariant AddressbookModel::headerData(int section,Qt::Orientation orientation, int role) const
    {
    if (orientation == Qt::Horizontal) 
    {
    if (role == Qt::DisplayRole) 
    {
     return addressBook.at(0).at(section);
    }
    }
    return QAbstractTableModel::headerData(section, orientation, role);
    }
    
    
    //data method
    QVariant AddressbookModel::data(const QModelIndex &index,
    int role) const
    {
    if (!index.isValid()) return QVariant();
    QStringList addressRecord = addressBook.at(index.row()+1);
    if (role == Qt::DisplayRole || role == Qt::EditRole) {
    return addressRecord.at(index.column());
    }
    if (role == Qt::ToolTipRole) {
    QString tip, key, value;
    tip = "<table>";
    int maxLines = addressRecord.count();
    for (int i = 0; i < maxLines; i++) {
    key = headerData(i, Qt::Horizontal, Qt::DisplayRole)
    .toString();
    value = addressRecord.at(i);
    if (!value.isEmpty())
    tip += QString("<tr><td><b>%1</b>: %2</td></tr>")
    .arg(key, value);
    }
    tip += "</table>";
    return tip;
    }
    return QVariant();
    }
    
    
    
    
    1 Reply Last reply
    0
    • VRoninV Offline
      VRoninV Offline
      VRonin
      wrote on last edited by VRonin
      #8
      1. pass your model through the Model Test
      2. make sure it survives and doesn't go out of scope as your views did

      "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
      ~Napoleon Bonaparte

      On a crusade to banish setIndexWidget() from the holy land of Qt

      T 1 Reply Last reply
      1
      • VRoninV VRonin
        1. pass your model through the Model Test
        2. make sure it survives and doesn't go out of scope as your views did
        T Offline
        T Offline
        thippu
        wrote on last edited by
        #9

        @VRonin Yeah, I did that no errors, bro.
        code what I did is: inside QWidget.

        new QAbstractItemModelTester(model,QAbstractItemModelTester::FailureReportingMode::Fatal);
        
        
        JonBJ 1 Reply Last reply
        0
        • T thippu

          @VRonin Yeah, I did that no errors, bro.
          code what I did is: inside QWidget.

          new QAbstractItemModelTester(model,QAbstractItemModelTester::FailureReportingMode::Fatal);
          
          
          JonBJ Online
          JonBJ Online
          JonB
          wrote on last edited by
          #10

          @thippu
          As @VRonin asked, how do we know from the code you post what the scope/lifetime of your AddressbookModel instance is?

          T 3 Replies Last reply
          0
          • JonBJ JonB

            @thippu
            As @VRonin asked, how do we know from the code you post what the scope/lifetime of your AddressbookModel instance is?

            T Offline
            T Offline
            thippu
            wrote on last edited by thippu
            #11

            @JonB I did convert all the objects from stack memory to heap, I'm not getting what you need?

            1 Reply Last reply
            0
            • JonBJ JonB

              @thippu
              As @VRonin asked, how do we know from the code you post what the scope/lifetime of your AddressbookModel instance is?

              T Offline
              T Offline
              thippu
              wrote on last edited by
              #12

              @JonB
              And also I did modelTest, There was no error.

              1 Reply Last reply
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              • JonBJ JonB

                @thippu
                As @VRonin asked, how do we know from the code you post what the scope/lifetime of your AddressbookModel instance is?

                T Offline
                T Offline
                thippu
                wrote on last edited by thippu
                #13

                @JonB changed all to the heap, I think they will stay till application die, right?
                code I have changed:

                Widget::Widget(QWidget *parent)
                : QWidget(parent)
                {
                QFile file("path");
                if(!file.open(QIODevice::ReadOnly|QIODevice::Text))
                {
                qDebug()<<"can't access the file";
                }
                QString *addresses=new QString(QString::fromUtf8(file.readAll()));
                Addressbookmodel *model=new Addressbookmodel(addresses,this);
                
                QListView *listView=new QListView();
                listView->setModel(model);
                listView->setModelColumn(0);
                listView->show();
                
                QTreeView *treeView=new QTreeView;
                treeView.setModel(model);
                treeView.show();
                
                QTableView *tableView=new QTableView;
                tableView.setModel(model);
                tableView.show();
                
                setMiniumSize(800,400);
                QVBoxLayout *Vlayout=new QVBoxLayout(this);
                Vlayout->addWidget(listView);
                Vlayout->addWidget(treeView);
                Vlayout->addWidget(tableView);
                }
                
                JonBJ 1 Reply Last reply
                0
                • T thippu

                  @JonB changed all to the heap, I think they will stay till application die, right?
                  code I have changed:

                  Widget::Widget(QWidget *parent)
                  : QWidget(parent)
                  {
                  QFile file("path");
                  if(!file.open(QIODevice::ReadOnly|QIODevice::Text))
                  {
                  qDebug()<<"can't access the file";
                  }
                  QString *addresses=new QString(QString::fromUtf8(file.readAll()));
                  Addressbookmodel *model=new Addressbookmodel(addresses,this);
                  
                  QListView *listView=new QListView();
                  listView->setModel(model);
                  listView->setModelColumn(0);
                  listView->show();
                  
                  QTreeView *treeView=new QTreeView;
                  treeView.setModel(model);
                  treeView.show();
                  
                  QTableView *tableView=new QTableView;
                  tableView.setModel(model);
                  tableView.show();
                  
                  setMiniumSize(800,400);
                  QVBoxLayout *Vlayout=new QVBoxLayout(this);
                  Vlayout->addWidget(listView);
                  Vlayout->addWidget(treeView);
                  Vlayout->addWidget(tableView);
                  }
                  
                  JonBJ Online
                  JonBJ Online
                  JonB
                  wrote on last edited by
                  #14

                  @thippu

                  Addressbookmodel *model=new Addressbookmodel(addresses,this);
                  treeView.setModel(&model);
                  tableView.setModel(&model);
                  

                  Now that model is a pointer, why the &s?

                  T 2 Replies Last reply
                  2
                  • JonBJ JonB

                    @thippu

                    Addressbookmodel *model=new Addressbookmodel(addresses,this);
                    treeView.setModel(&model);
                    tableView.setModel(&model);
                    

                    Now that model is a pointer, why the &s?

                    T Offline
                    T Offline
                    thippu
                    wrote on last edited by
                    #15

                    @JonB Sorry, typo mistake.

                    1 Reply Last reply
                    0
                    • JonBJ JonB

                      @thippu

                      Addressbookmodel *model=new Addressbookmodel(addresses,this);
                      treeView.setModel(&model);
                      tableView.setModel(&model);
                      

                      Now that model is a pointer, why the &s?

                      T Offline
                      T Offline
                      thippu
                      wrote on last edited by
                      #16

                      @JonB I did copy and paste from the early reply, So

                      1 Reply Last reply
                      0
                      • VRoninV Offline
                        VRoninV Offline
                        VRonin
                        wrote on last edited by
                        #17

                        I'm surprised you don't get into stack overflow.
                        AddressbookModel::rowCount and AddressbookModel::columnCount form an infinitely deep tree.

                        You should return 0; if the parent argument isValid()

                        "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                        ~Napoleon Bonaparte

                        On a crusade to banish setIndexWidget() from the holy land of Qt

                        T 2 Replies Last reply
                        1
                        • VRoninV VRonin

                          I'm surprised you don't get into stack overflow.
                          AddressbookModel::rowCount and AddressbookModel::columnCount form an infinitely deep tree.

                          You should return 0; if the parent argument isValid()

                          T Offline
                          T Offline
                          thippu
                          wrote on last edited by
                          #18

                          @VRonin okay,
                          In the Addressbookmodel.cpp
                          I changed the code to :

                          int Addressbookmodel::rowCount(const QModelIndex &parent) const
                          {
                             if(parent.isValid())
                          {
                            return 0;
                          }
                          return addressbook.count-2;
                          }
                          
                          
                          int Addressbookmodel::columnCount(const QModelIndex &parent)
                          const
                          {
                            if(parent.isValid())
                            {
                             return 0;
                            }
                          return addressbook.at(0).count();
                          }
                          
                          

                          I don't know why it is not used in the book and why am not getting data on the widgets still?.

                          1 Reply Last reply
                          0
                          • VRoninV VRonin

                            I'm surprised you don't get into stack overflow.
                            AddressbookModel::rowCount and AddressbookModel::columnCount form an infinitely deep tree.

                            You should return 0; if the parent argument isValid()

                            T Offline
                            T Offline
                            thippu
                            wrote on last edited by
                            #19

                            @VRonin Can share me an example that helps me to understand how to create QTreeView model and subclass it?, so from this I can able to create my own models successfully.

                            VRoninV 1 Reply Last reply
                            0
                            • T thippu

                              @VRonin Can share me an example that helps me to understand how to create QTreeView model and subclass it?, so from this I can able to create my own models successfully.

                              VRoninV Offline
                              VRoninV Offline
                              VRonin
                              wrote on last edited by
                              #20

                              @thippu said in Data not displaying on the QTreeView, QTableView,QListView classes:

                              Can share me an example that helps me to understand how to create QTreeView model and subclass it?

                              http://doc.qt.io/qt-5/qtwidgets-itemviews-simpletreemodel-example.html

                              "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                              ~Napoleon Bonaparte

                              On a crusade to banish setIndexWidget() from the holy land of Qt

                              T 1 Reply Last reply
                              1
                              • VRoninV VRonin

                                @thippu said in Data not displaying on the QTreeView, QTableView,QListView classes:

                                Can share me an example that helps me to understand how to create QTreeView model and subclass it?

                                http://doc.qt.io/qt-5/qtwidgets-itemviews-simpletreemodel-example.html

                                T Offline
                                T Offline
                                thippu
                                wrote on last edited by
                                #21

                                @VRonin , Thank you.

                                1 Reply Last reply
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