Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
  • Search
  • Get Qt Extensions
  • Unsolved
Collapse
Brand Logo
  1. Home
  2. Qt Development
  3. General and Desktop
  4. Encoding in the QTableView

Encoding in the QTableView

Scheduled Pinned Locked Moved Solved General and Desktop
47 Posts 3 Posters 14.8k Views
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • mrjjM mrjj

    @ro12man3
    well when u create your delegate object
    you also give it a Hash list with the town names.
    so in displayText()
    it can look up in the list the name to use from the number from DB.

    ro12man3R Offline
    ro12man3R Offline
    ro12man3
    wrote on last edited by
    #14

    @mrjj unfortunately, it doesn't work. I read that for solving that problem I need to change TableView to TableWidget and use QTableWidgetItem. How to change the numbers in that variant?

    1 Reply Last reply
    0
    • mrjjM Offline
      mrjjM Offline
      mrjj
      Lifetime Qt Champion
      wrote on last edited by
      #15

      @ro12man3 said:

      How to change the numbers in that variant?

      Hi Im not sure what you ask about ?

      QTableWidgetItem is not a variant.

      ro12man3R 1 Reply Last reply
      0
      • mrjjM mrjj

        @ro12man3 said:

        How to change the numbers in that variant?

        Hi Im not sure what you ask about ?

        QTableWidgetItem is not a variant.

        ro12man3R Offline
        ro12man3R Offline
        ro12man3
        wrote on last edited by
        #16

        @mrjj well... I talk about how to make changing the numbers to text in my tableview(or widget). I wrote

        QHash< int, QString> hash;
         hash.insert(100, "Jackson");
        

        and it doesn't change nothing in the table

        1 Reply Last reply
        0
        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #17

          Where's that hash located ?
          Did you set your custom QStyledItem delegate on the correct column of your QTableView ?
          Are you sure that the volume contains the correct values ?

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

          ro12man3R 1 Reply Last reply
          0
          • SGaistS SGaist

            Where's that hash located ?
            Did you set your custom QStyledItem delegate on the correct column of your QTableView ?
            Are you sure that the volume contains the correct values ?

            ro12man3R Offline
            ro12man3R Offline
            ro12man3
            wrote on last edited by ro12man3
            #18

            @SGaist this is the code

            void MainWindow::on_pushButton_clicked() // I click and the quiery result is showing in the qtableview
            {
            QSqlQueryModel * model = new QSqlQueryModel(0);
            QHash< int, QString> hash;
             hash.insert(100, "Jackson");
            model->setQuery("select city-codes from country");
            ui->tableView->setModel(model);
            }
            
            1 Reply Last reply
            0
            • SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on last edited by
              #19

              That hash is destroyed at the end of on_pushButton_clicked

              Interested in AI ? www.idiap.ch
              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

              ro12man3R 1 Reply Last reply
              0
              • SGaistS SGaist

                That hash is destroyed at the end of on_pushButton_clicked

                ro12man3R Offline
                ro12man3R Offline
                ro12man3
                wrote on last edited by
                #20

                @SGaist so what I need to do for the correct changing values in my tableview?
                Where I need to write the QHash function?

                1 Reply Last reply
                0
                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #21

                  Either in your QStyledItemDelegate or as @mrjj suggested pass it to the delegate e.g. at construction time.

                  Interested in AI ? www.idiap.ch
                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                  ro12man3R 1 Reply Last reply
                  0
                  • SGaistS SGaist

                    Either in your QStyledItemDelegate or as @mrjj suggested pass it to the delegate e.g. at construction time.

                    ro12man3R Offline
                    ro12man3R Offline
                    ro12man3
                    wrote on last edited by
                    #22

                    @SGaist what will be more simple? Cause I don't know how to make that. Sorry about my not big skills in qt

                    mrjjM 1 Reply Last reply
                    0
                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #23

                      In your QStyledItemDelegate, read your file and build the hash with its content. Then in your displayText reimplementation return _hash.value(value.toInt(), tr("Not found"));

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                      1 Reply Last reply
                      1
                      • ro12man3R ro12man3

                        @SGaist what will be more simple? Cause I don't know how to make that. Sorry about my not big skills in qt

                        mrjjM Offline
                        mrjjM Offline
                        mrjj
                        Lifetime Qt Champion
                        wrote on last edited by
                        #24

                        @ro12man3
                        hi
                        Starting with models and view are not best intro to Qt.
                        They are very powerful but does demand some c++ skills and reading the docs.

                        Sometimes code is easier to understand so I made u sample with @SGaist help.

                        It has a list of names and if it sees Lars, it replaced it with BANNED.
                        For your code, you will use the hash to look up the name from the code.

                        https://www.dropbox.com/s/vsiqjrr41jhafqo/myfirstview.zip?dl=0

                        the key points to understand is:
                        we make a new class to override the default behaviour

                        class MyDelegate : public QStyledItemDelegate {
                        public:
                        MyDelegate(QObject* parent)
                        : QStyledItemDelegate(parent) {}
                        virtual QString displayText(const QVariant& value, const QLocale& locale) const;
                        };

                        We set this delegate ONLY to the column we need.

                        • ui->tableView->setItemDelegateForColumn(0, new MyDelegate(this));

                        the displayText is the key function.:

                        QString MyDelegate::displayText(const QVariant& value, const QLocale& locale) const {
                        if (value.toString().compare("Lars") == 0) // if found
                        return "BANNED";
                        else
                        return value.toString(); // else just return data unchanged
                        }

                        Here u will replace the city-code with names using the hash.

                        Hope this helps you.

                        ro12man3R 1 Reply Last reply
                        1
                        • mrjjM mrjj

                          @ro12man3
                          hi
                          Starting with models and view are not best intro to Qt.
                          They are very powerful but does demand some c++ skills and reading the docs.

                          Sometimes code is easier to understand so I made u sample with @SGaist help.

                          It has a list of names and if it sees Lars, it replaced it with BANNED.
                          For your code, you will use the hash to look up the name from the code.

                          https://www.dropbox.com/s/vsiqjrr41jhafqo/myfirstview.zip?dl=0

                          the key points to understand is:
                          we make a new class to override the default behaviour

                          class MyDelegate : public QStyledItemDelegate {
                          public:
                          MyDelegate(QObject* parent)
                          : QStyledItemDelegate(parent) {}
                          virtual QString displayText(const QVariant& value, const QLocale& locale) const;
                          };

                          We set this delegate ONLY to the column we need.

                          • ui->tableView->setItemDelegateForColumn(0, new MyDelegate(this));

                          the displayText is the key function.:

                          QString MyDelegate::displayText(const QVariant& value, const QLocale& locale) const {
                          if (value.toString().compare("Lars") == 0) // if found
                          return "BANNED";
                          else
                          return value.toString(); // else just return data unchanged
                          }

                          Here u will replace the city-code with names using the hash.

                          Hope this helps you.

                          ro12man3R Offline
                          ro12man3R Offline
                          ro12man3
                          wrote on last edited by ro12man3
                          #25

                          @mrjj ohhh thank you! It works!! Thank you very much.

                          But I have 40 values that I will need to change(if it will be in quiery result).

                          1. I can't write 40 "else if".. "else if"... "else if".... That's unlogic.
                          2. I need to write all that values in support *.txt file(or another, the main is a simple format for editing), cause if I will write all that values in the program and then I will need to add new values...That's will be very uncomfortable.

                          I see the method of the working the function so:
                          The function is searching the values(from *.txt file) that has a quiery result. If it will find, then it will change to another every value.

                          But...how make that in reality?

                          1 Reply Last reply
                          0
                          • mrjjM Offline
                            mrjjM Offline
                            mrjj
                            Lifetime Qt Champion
                            wrote on last edited by
                            #26

                            hi
                            it sounds like your best way would to read in
                            the text file to a hash.
                            and use that hash in displayText
                            I agree, using if for 40 values would be nasty :)

                            How does your text file look like?

                            ro12man3R 1 Reply Last reply
                            0
                            • mrjjM mrjj

                              hi
                              it sounds like your best way would to read in
                              the text file to a hash.
                              and use that hash in displayText
                              I agree, using if for 40 values would be nasty :)

                              How does your text file look like?

                              ro12man3R Offline
                              ro12man3R Offline
                              ro12man3
                              wrote on last edited by
                              #27

                              @mrjj I didn't create that file, cause I have no idea. Well, every variant will be good. The main is the working code :D

                              Do you think that *.txt file should looks so:

                              hash.insert("123", "Jack Sparrow");
                              hash.insert("134", "Elvis Presley");
                              hash.insert("201", "Walter White");
                              ........
                              

                              ?

                              mrjjM 1 Reply Last reply
                              0
                              • ro12man3R ro12man3

                                @mrjj I didn't create that file, cause I have no idea. Well, every variant will be good. The main is the working code :D

                                Do you think that *.txt file should looks so:

                                hash.insert("123", "Jack Sparrow");
                                hash.insert("134", "Elvis Presley");
                                hash.insert("201", "Walter White");
                                ........
                                

                                ?

                                mrjjM Offline
                                mrjjM Offline
                                mrjj
                                Lifetime Qt Champion
                                wrote on last edited by
                                #28

                                @ro12man3
                                Hi
                                For me it sounds like you would have a text file with
                                1000, NAME1
                                1001, NAME2

                                so when u see int 1000, u want "NAME" etc.

                                So your task is to look at QFile and read in a text file with your format and stuff it into a hash.
                                Then use it.

                                ro12man3R 1 Reply Last reply
                                0
                                • mrjjM mrjj

                                  @ro12man3
                                  Hi
                                  For me it sounds like you would have a text file with
                                  1000, NAME1
                                  1001, NAME2

                                  so when u see int 1000, u want "NAME" etc.

                                  So your task is to look at QFile and read in a text file with your format and stuff it into a hash.
                                  Then use it.

                                  ro12man3R Offline
                                  ro12man3R Offline
                                  ro12man3
                                  wrote on last edited by
                                  #29

                                  @mrjj ok, I understand how to read the file and search the values. I don't understand another thing.
                                  On example=, the function will read the .txt file and it will find some value. Let it be 2900.
                                  In txt file it will be looking:
                                  2900, "Jackson"

                                  How to convert to "Jackson"? I don't know how to write that in a hash. How the hash will look the "convert value"?

                                  mrjjM 1 Reply Last reply
                                  0
                                  • ro12man3R ro12man3

                                    @mrjj ok, I understand how to read the file and search the values. I don't understand another thing.
                                    On example=, the function will read the .txt file and it will find some value. Let it be 2900.
                                    In txt file it will be looking:
                                    2900, "Jackson"

                                    How to convert to "Jackson"? I don't know how to write that in a hash. How the hash will look the "convert value"?

                                    mrjjM Offline
                                    mrjjM Offline
                                    mrjj
                                    Lifetime Qt Champion
                                    wrote on last edited by mrjj
                                    #30

                                    @ro12man3
                                    say
                                    u define the hash like
                                    QHash<int, QString> Hash;
                                    it means we use int as key and get string as result
                                    so
                                    QString Name=hash[2900];
                                    would give us "Jackson" in name;

                                    please read doc on how it works.
                                    http://doc.qt.io/qt-5/qhash.html

                                    so you would read all lines from text file and insert into hash.

                                    ro12man3R 1 Reply Last reply
                                    1
                                    • mrjjM mrjj

                                      @ro12man3
                                      say
                                      u define the hash like
                                      QHash<int, QString> Hash;
                                      it means we use int as key and get string as result
                                      so
                                      QString Name=hash[2900];
                                      would give us "Jackson" in name;

                                      please read doc on how it works.
                                      http://doc.qt.io/qt-5/qhash.html

                                      so you would read all lines from text file and insert into hash.

                                      ro12man3R Offline
                                      ro12man3R Offline
                                      ro12man3
                                      wrote on last edited by
                                      #31

                                      @mrjj woooow thank you! You are the master! :) I understand, very clever idea!

                                      I will try that in the morning.

                                      1 Reply Last reply
                                      0
                                      • mrjjM Offline
                                        mrjjM Offline
                                        mrjj
                                        Lifetime Qt Champion
                                        wrote on last edited by mrjj
                                        #32

                                        well for 40 lookups its more fun that tons of ifs
                                        if u make a text file with
                                        ID, NAME
                                        like
                                        1000, TOWN
                                        1001, TOWN2
                                        1002, TOWN3

                                        so u need to ( code handwritten fast, not tested. u need to add includes)

                                        QFile file("c:/mynames.txt");
                                        if(!file.open(QIODevice::ReadOnly)) {
                                        QMessageBox::information(0, "error", file.errorString());
                                        }

                                        QTextStream in(&file);
                                        while(!in.atEnd()) {
                                        QString line = in.readLine(); // get a line from file
                                        QStringList fields = line.split(","); <<< KEY point. we ask it to split the text at "," to a list
                                        /// now fields[0] is first part and fields[1] is rest
                                        // so
                                        hash[fields[0].toInt()] = fields[1] ; // store name under key
                                        }

                                        file.close();

                                        ro12man3R 1 Reply Last reply
                                        1
                                        • mrjjM mrjj

                                          well for 40 lookups its more fun that tons of ifs
                                          if u make a text file with
                                          ID, NAME
                                          like
                                          1000, TOWN
                                          1001, TOWN2
                                          1002, TOWN3

                                          so u need to ( code handwritten fast, not tested. u need to add includes)

                                          QFile file("c:/mynames.txt");
                                          if(!file.open(QIODevice::ReadOnly)) {
                                          QMessageBox::information(0, "error", file.errorString());
                                          }

                                          QTextStream in(&file);
                                          while(!in.atEnd()) {
                                          QString line = in.readLine(); // get a line from file
                                          QStringList fields = line.split(","); <<< KEY point. we ask it to split the text at "," to a list
                                          /// now fields[0] is first part and fields[1] is rest
                                          // so
                                          hash[fields[0].toInt()] = fields[1] ; // store name under key
                                          }

                                          file.close();

                                          ro12man3R Offline
                                          ro12man3R Offline
                                          ro12man3
                                          wrote on last edited by
                                          #33

                                          @mrjj thank you very much!! I will try that. If I wiil edit this, I will write here the correct code.
                                          Thank you for your helping!

                                          mrjjM 1 Reply Last reply
                                          0

                                          • Login

                                          • Login or register to search.
                                          • First post
                                            Last post
                                          0
                                          • Categories
                                          • Recent
                                          • Tags
                                          • Popular
                                          • Users
                                          • Groups
                                          • Search
                                          • Get Qt Extensions
                                          • Unsolved