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No such file or directory #include <QtWidgets>

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  • C Offline
    C Offline
    clochydd
    wrote on last edited by
    #2

    Hi, and welcome to DevNet,
    You should only add QT += widgets in your .pro file and not include QtWidgets

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    • N Offline
      N Offline
      nandhu_kp
      wrote on last edited by
      #3

      greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

      use this in your .pro file

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      • T Offline
        T Offline
        tymop
        wrote on last edited by
        #4

        I tried your 2 solutions, but i still have a problem:
        A lot of functions are not declared.
        This is the example I tested: childwidget (with the modifications you gave me)

        childwidget.pro:
        @greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

        SOURCES = main.cpp

        install

        target.path = $$[QT_INSTALL_EXAMPLES]/widgets/tutorials/widgets/childwidget
        INSTALLS += target
        @

        main.cpp
        @//! [main program]
        //#include <QtWidgets>

        int main(int argc, char *argv[])
        {
        QApplication app(argc, argv);
        QWidget window;
        window.resize(320, 240);
        window.setWindowTitle(QApplication::translate("childwidget", "Child widget"));
        window.show();

        //! [create, position and show]
        QPushButton *button = new QPushButton(
        QApplication::translate("childwidget", "Press me"), &window);
        button->move(100, 100);
        button->show();
        //! [create, position and show]
        return app.exec();
        }
        //! [main program]
        @

        And this is an extract of the errors (only the 2 first) i have when i compile:

        @/opt/qt/5.2.1/gcc_64/examples/widgets/tutorials/widgets/childwidget/main.cpp:46: erreur : 'QApplication' was not declared in this scope
        QApplication app(argc, argv);
        ^
        /opt/qt/5.2.1/gcc_64/examples/widgets/tutorials/widgets/childwidget/main.cpp:46: erreur : expected ';' before 'app'
        QApplication app(argc, argv);
        ^
        @

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        • X Offline
          X Offline
          Xander84
          wrote on last edited by
          #5

          you have to include the Qt classes you need, for a simple program like this you can include the whole module but I would not recommend that because it will drastically increase compile time.
          @
          #include <QApplication>
          #include <QWidget>
          #include <QPushButton>
          @
          essentially you have to include all Qt classes like this, if you want to do it right. :)

          if you are lazy or have a super fast computer you can include whole Qt modules at once with
          @
          #include <QtCore>
          #include <QtGui>
          #include <QtWidgets>
          ...
          @
          i would only use that if you need many classes from one module.

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          • T Offline
            T Offline
            tymop
            wrote on last edited by
            #6

            Thank you,
            with your help, I managed to run the example.

            I find it unfortunate that the examples do not work as they are.
            That make the learning more difficult.

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            • C Offline
              C Offline
              clochydd
              wrote on last edited by
              #7

              Usually, the examples work as they are.
              I have opened your examples/widgets/tutorials/addressbook/part1 with the Qt Creator, built it and had no errors.
              How did you work with the example?

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              • T Offline
                T Offline
                tymop
                wrote on last edited by
                #8

                That is strange, because, as I said, I just install qtcreator with the script qt-opensource-linux-x64-1.5.0-2-online.run, in the /opt directory/

                Then, I open it and tried some examples, and I have the same problem eact time.

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                • X Offline
                  X Offline
                  Xander84
                  wrote on last edited by
                  #9

                  Do you open the examples from Qt creator directly? (Welcome -> examples)
                  they should work out of the box.

                  And is there a reason you use and old version of Qt? I mean that is like 2 years old or something. :)

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                  • T Offline
                    T Offline
                    tymop
                    wrote on last edited by
                    #10

                    Do you open the examples from Qt creator directly? No : I opened with open file or project

                    And is there a reason you use and old version of Qt? I used the version found on the site web qt-opensource-linux-x64-1.5.0-2-online.run

                    I tried another version comming from the ubuntu deposite(Qt Creator 3.0.1) , but there was another problem because the binary /usr/bin/qmlpuppet was not installed (because not in the ubuntu deposite), and I did not find he way to install it.

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                    • X Offline
                      X Offline
                      Xander84
                      wrote on last edited by
                      #11

                      I have Qt 5.2.1 running on my Ubuntu machine, using the online installer (qt-linux-opensource-1.5.0-x64-online.run in my case), worked like a charm so I don't know what you did. You have so weird bugs, I have no idea why, sorry.

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                      • C Offline
                        C Offline
                        clochydd
                        wrote on last edited by
                        #12

                        I think we should try to find out, what happend to your install.
                        If you look at your Creator's About screen, do you see this:
                        Qt Creator 3.1.0 (opensource)
                        Based on Qt 5.2.1 (GCC 4.6.1, 64 bit)
                        Try to compare your Creator settings with "this: ":http://qt-project.org/doc/qtcreator-3.1/creator-configuring.html

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                        • T Offline
                          T Offline
                          tymop
                          wrote on last edited by
                          #13

                          Thank form your help.
                          This is the version installed
                          @Qt Creator 3.0.1
                          Based on Qt 5.2.1 (GCC 4.8.2, 64 bit)
                          Built on Apr 9 2014 at 09:12:59
                          @

                          And the version from the .run
                          @Qt Creator 3.1.0 (opensource)
                          Basé sur Qt 5.2.1 (GCC 4.6.1, 64 bit)
                          Compilé le Apr 14 2014 à 15:03:42
                          Depuis la révision 52592aa879@

                          But it is strange because, now, the qtcreator installed from the unbuntu deposites is now working. Maybe the .run install added the missing files ?

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                          • C Offline
                            C Offline
                            clochydd
                            wrote on last edited by
                            #14

                            As the Qt Creator 3.1.0 is the newest version it would be better to use it instead of 3.0.1 - but if you succeed with 3.0.1 you shouldn't have problems.
                            Perhaps you may give 5.3.0 a try when it's released in a few days.

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                            • T tymop

                              Hello,
                              I am a beginner with qt, and I just download and install the last vesion of qt with this link "qt-opensource-linux-x64-1.5.0-2-online.run":http://download.qt-project.org/official_releases/online_installers/qt-opensource-linux-x64-1.5.0-2-online.run

                              Then, I tried some examples to understand how qt works, but i have the save error with each examle I tried. This is an example
                              @/opt/qt/5.2.1/gcc_64/examples/widgets/tutorials/addressbook/part1/addressbook.cpp:41: erreur : QtWidgets: No such file or directory
                              #include <QtWidgets>@

                              always the same error : @erreur : QtWidgets: No such file or directory #include <QtWidgets>@

                              Is there anything especial to do to work with the examples ?

                              what is the problem ?

                              Thank a lot for your help.

                              A Offline
                              A Offline
                              AlexeiK
                              wrote on last edited by
                              #15

                              @tymop
                              Провести настройку комплектов под Qt5
                              На вкладке Проекты провести настройку проекта заново с верными компеляторами

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