SpreadSheet (Functionality)

Context

In the lecture on QMainWindow, we wrote the code for the graphical and set of actions for our main SpreadSeet application. Now we will focus on writing a set of basic functionality.

For the full Fonctionality, you’ll need a deep understanding on inheritance and

  • QTableSelectedRange
  • Sorting using keys.
  • Introducing a formula for each Cell ( you must use Inheritance to specialize a QTalbeWidget).

Those concepts are out of the scope of this course and will much of a lost of time. But for the curious programmer, they could try to achieve the full functionality.

In the our last iteration of the SpreadSheet we did obtain an application with:

  • Menu Bar
  • Two tools bars
  • Status bar to print the informations

You should have an application that looks like that :

Starter Application with actions and menus.

If you missed or have a problem with the previous week, Here is the link for the application (Preferably you should work with your own version to have a feeling of completion!).

Here is the Starter_code.zip

Remarks

We did add the following modifications:

  1. The updateStatusBar now takes two ints in order to syncrhonize with the selected item from the spreadsheet. 
    void updateStatusBar(int, int)

Here is the implementation of this function:

void SpreadSheet::updateStatusBar(int row, int col)
{
    QString cell{"(%0, %1)"};
   cellLocation->setText(cell.arg(row+1).arg(col+1));

}

Which simply change the cellLocation text with the current cell coordinates.

  1. We added the makeConnexion() function to connect all the actions. Here is the content of the this function:

    void SpreadSheet::makeConnexions()
{

// --------- Connexion for the  select all action ----/
connect(all, &QAction::triggered,
        spreadsheet, &QTableWidget::selectAll);

// Connection for the  show grid
connect(showGrid, &QAction::triggered,
        spreadsheet, &QTableWidget::setShowGrid);

//Connection for the exit button
connect(exit, &QAction::triggered, this, &SpreadSheet::close);

//connectting the chane of any element in the spreadsheet with the update status bar
connect(spreadsheet, &QTableWidget::cellClicked, this,  &SpreadSheet::updateStatusBar);
}

Go Cell

Now we will add the function for the goCell action. For that, we need to create a Dialog for the user to select a cell.

We did already achieved that in Go Dialog .

If you lost that project, here are the steps to acomplish that:

  1. Create a Form Class:

  2. Using the designer obtain the following the form:

    Ui components of the Go Dialog.

  3. Add the regular expression validator for the lineEdit:

     //Validating the regular expression
 QRegExp regCell{"[A-Z][1-9][0-9]{0,2}"};

 //Validating the regular expression
 ui->lineEdit->setValidator(new QRegExpValidator(regCell));

  4. Add a public Getter for the line edit Text to get the cell address:

         QString GoCellDialog::cell() const
     {
         return ui->lineEdit->text();
     }

No we are setup to create the interesting connexion between the goCell action:

  1. First we will create the proper slot called goCellSlot to respond to the action trigger.

     private slots:
 void goCellSlot();            // Go to a Cell slot
  2. connect the action to its proper slot in the makeConnexions function: 
    //Connextion between the gocell action and the gocell slot
connect(goCell, &QAction::triggered, this, &SpreadSheet::goCellSlot);

  3. Now for the fun part. We will implement the goCellSlot() function:

     void SpreadSheet::goCellSlot()
 {
     //Creating the dialog
     GoCellDialog D;

     //Executing the dialog and storing the user response
     auto reply = D.exec();

     //Checking if the dialog is accepted
     if(reply == GoCellDialog::Accepted)
     {

         //Getting the cell text
         auto cell = D.cell();

         //letter distance
         int row = cell[0].toLatin1() - 'A';
         cell.remove(0,1);

         //second coordinate
         int col =  cell.toInt();


         //changing the current cell
         spreadsheet->setCurrentCell(row, col-1);
     }
 }
Go to Cell dialog and response.

Find Dialog

We will move now for the Find dialog. This dialog prompts the user for a input and seek a cell that contains the entered text.

  1. Create a Form Class with the following ui:
Find Dialog ui form.
  1. Add a Getter to obtain the searched text.
  2. Implements the connexion between the dialog and the find function:

Here is a set of useful information about the QTableWidget class:

  • The method rowCount() gives the number of rows.
  • The method columnCount() gives the number of columns in the spreadsheet.
  • The Method item(int i, int j) return a pointer on the cell indexed by i and j.

  • If this pointer is not null, you could get its content by the method text() which returns a QString.

  • Finally, the method to change the focused cell is 
      spreadsheet->setCurrentCell(int i, int j);
Find dialog illustration

Saving and loading files

For our final task, we will learn how to save the content of our spreadsheet in a simple format. Since a spreadsheet is not forcefully tabular, it will be a waste to save all the empty data. Hence, we will choose a simple format that store the coordinates and the content of the non empty cells.

i1, j1, content1
i2, j2, content2
.
.
.

Saving Content

We will start by writing a private function saveContent(QSTring filename) to save the content of our spreadsheet in a text file.

  1. We will add the declaration in the header file:

     protected:
     void saveContent(QString filename)const;
  2. For the implementation, we will using two classes:
    • QFile which provides an interface to read and write in files.
    • QTextStream for manipulating objects with a stream such as a file.
  3. Here is the complete implementation of this function: 
     void SpreadSheet::saveContent(QString filename) const
 {

     //Gettign a pointer on the file
     QFile file(filename);

     //Openign the file
     if(file.open(QIODevice::WriteOnly))  //Opening the file in writing mode
     {
         //Initiating a stream using the file
         QTextStream out(&file);

         //loop to save all the content
         for(int i=0; i < spreadsheet->rowCount();i++)
             for(int j=0; j < spreadsheet->columnCount(); j++)
             {
                 auto cell = spreadsheet->item(i, j);

                 //Cecking if the cell is non empty
                 if(cell)
                 out << cell->row() << ", "<< cell->column() << ", " << cell->text() << endl;
             }

     }
     file.close();
 }

Save File action

Now that we have an operational saveContent function, we could focus on the slot itself.

So first we will create a slot to respond to the action trigger in the header.

private slots:
    void saveSlot();             //Slot to save the content of the file

Now we will add the connexion in the makeConnexion function:

   //Connexion for the saveFile
   connect(save, &QAction::triggered, this, &SpreadSheet::saveSlot);

Finally for the interesting part, the implementation of the slot


void SpreadSheet::saveSlot()
{
    //Creating a file dialog to choose a file graphically
    auto dialog = new QFileDialog(this);

    //Check if the current file has a name or not
    if(currentFile == "")
    {
       currentFile = dialog->getSaveFileName(this,"choose your file");

       //Update the window title with the file name
       setWindowTitle(currentFile);
    }

   //If we have a name simply save the content
   if( currentFile != "")
   {
           saveContent(currentFile);
   }
}

Load File

Now it is your turn to write the implementation for the load file action.

That will be all for our humble application. In your free time, try to add more functionalities.

Text Editor

For your first example, we will playing the Designer for a fast application creation. The application is from Qt Examples and is a simple text editor program built around QPlainText.

Example for the main text editor.

We will mainly use the designer for a rapid design of it features. But if you feel adventurous you can write all in using code.

Here is an overview of the menus:

Set of menus for our application.

Creating the project.

First create a new project called WordText using the following steps:

  1. Choose a QT Widgets Application.
  2. Name your project WordText
  3. Inherit now from QMainWindow.
  4. Choose all the remaining default choices.

Open the form You’ll see that it has now an empty menu and already a defined menu and satatus bars.

First empty QMainWindow Project.

Icons

  1. Add a resource file and add a set of predefined icons from you choice.

Using the designer add all the menues in the image description.

To add a menu you simply enter its name. You can edit its properties in the object Inspector.

Actions

Easy enough you can also add your actions to a menu by simply clicking the text in the menu.

Functionality

Now using your knowledge, try to code the functionality of the Text Editor. Here is a link for QPlainTextEdit.

Good luck