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Problem with creating first project and the book "C++-gui-programming-with-qt-4-2ndedition"

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  • K Offline
    K Offline
    Kurdman
    wrote on last edited by
    #3

    I'm really confused.
    I made an Empty Qtproject and wrote this code:

    @#include <QApplication>
    #include <QLabel>

    int main(int argc,char *argv[])
    {
    QApplication app(argc, argv);
    QLabel *label = new QLabel("Hello Qt!");
    label->show();
    return app.exec();
    }@

    But I get 4 issues!
    They are as follows.What is the problem please?

    C:\Qt\Qt5.3.0\Tools\QtCreator\bin\untitled\untitled.pro:4: error: Extra characters after test expression.
    C:\Qt\Qt5.3.0\Tools\QtCreator\bin\untitled\untitled.pro:6: error: Extra characters after test expression.
    C:\Qt\Qt5.3.0\Tools\QtCreator\bin\untitled\untitled.pro:7: error: Assignment needs exactly one word on the left hand side.
    C:\Qt\Qt5.3.0\Tools\QtCreator\bin\untitled\untitled.pro:9: error: Extra characters after test expression.

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    • JeroentjehomeJ Offline
      JeroentjehomeJ Offline
      Jeroentjehome
      wrote on last edited by
      #4

      Hi,
      The errors are in your project file!! (untitled.pro) with the lines 4, 6, 7, 9
      Show that piece of code and we might solve the problem.
      Also, creating a project in your Qt folder is IMHO not a smart thing to do.
      When using a QLabel you should have generated a new->QWidget project like sierdzio said ;-)

      Greetz, Jeroen

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      • sierdzioS Offline
        sierdzioS Offline
        sierdzio
        Moderators
        wrote on last edited by
        #5

        Put C++ code (the whole snippet above) into main.cpp file.

        In .pro file, type this:
        @
        QT += core gui widgets

        SOURCES += main.cpp
        @

        Should work.

        (Z(:^

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        • K Offline
          K Offline
          Kurdman
          wrote on last edited by
          #6

          I made a Qt Widget Application like what "sierdzio" has said, named "test.pro".
          These are the things which are written on it be default:

          @#-------------------------------------------------

          Project created by QtCreator 2014-06-11T11:37:42

          #-------------------------------------------------

          QT += core gui

          greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

          TARGET = test
          TEMPLATE = app

          SOURCES += main.cpp
          mainwindow.cpp

          HEADERS += mainwindow.h

          FORMS += mainwindow.ui
          @

          Now where to put that simple snip code please?

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          • JeroentjehomeJ Offline
            JeroentjehomeJ Offline
            Jeroentjehome
            wrote on last edited by
            #7

            Hi,
            When you generate a "empty" widget project, you get a project file (test.pro) a main file (main.cpp) and your first class declaration (MainWindow.cpp) if you selected to add a mainwindow widget to the project.
            Your main function in main.cpp should look like this:
            @
            int main(int argc,char *argv[])
            {
            QApplication app(argc, argv);
            QLabel *label = new QLabel("Hello Qt!");
            label->show();
            return app.exec();
            }
            @
            This is to generate a QApplication which you need 1 off in every program (or a QCoreApplication etc if no widgets are used etc). The QApplication handles the Event loop and a hole lot of other stuff.
            Your MAinWindow class is not used for now, but that will come later.

            Greetz, Jeroen

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            • K Offline
              K Offline
              Kurdman
              wrote on last edited by
              #8

              Completely mixed up!

              Please read the thread from beginning. My question is very simple. I gave the first example of the book and said how to make a project and put that snip code into that and run it.
              I should first solve this problem and then be familiar with other parts of Qt.
              This is the window of test.pro which I created it:
              http://tinypic.com/view.php?pic=5ltrgj&s=8#.U5hiG3KSzis

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              • JeroentjehomeJ Offline
                JeroentjehomeJ Offline
                Jeroentjehome
                wrote on last edited by
                #9

                No, I'm not mixed up!
                My explanation is very basic and noob proof.

                Don't change the pro file! Leave it alone, this comes later. The pro file is used by QMake (you will learn later) how to compile.

                Then open the source folder (you know the little triangle in front of it). Then double click the main.cpp file (this will open it in creator). Then place your code there in the main function and delete the MainWindow creation for now.
                You should get a window with only a button into it. It can't get any more simple then that!

                Greetz, Jeroen

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                • K Offline
                  K Offline
                  Kurdman
                  wrote on last edited by
                  #10

                  After much attempt I could to run the code. It worked. Please look at my code window screen in below link. Is everything fine to you?
                  http://tinypic.com/r/1265n3k/8

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                  • C Offline
                    C Offline
                    clochydd
                    wrote on last edited by
                    #11

                    That looks fine and you should no get that window with one button.
                    And you now have a way to work through the book using the Creator.

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                    • K Offline
                      K Offline
                      Kurdman
                      wrote on last edited by
                      #12

                      OK mate. Thank you very much for assigning your time for helping me.

                      I try to read that book carefully but it doesn't seem to be clear for beginners (for example now I should try to solve this: From a command prompt, change the directory to "test" and type qmake -project).

                      Thanks also to all of other guys that helped me.

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                      • C Offline
                        C Offline
                        clochydd
                        wrote on last edited by
                        #13

                        If you want to know how to build projects without the IDE, working from the command prompt would help.
                        But it is not necessary as you may work completely from the Creator and the Qt Creator runs qmake and make for you.

                        I think it is now helpful, if you try one of the examples supplied with Creator and then step back to the book and merge the code from the book to the IDE.

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                        0
                        • K Offline
                          K Offline
                          Kurdman
                          wrote on last edited by
                          #14

                          I'm sorry, I don't know at all how to try one of those examples. And I wrote that qmake and command prompt because they exist in the book and I just quoted them from the book.
                          Since I read that not clear book I have to follow what it says:(.

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                          • A Offline
                            A Offline
                            andreyc
                            wrote on last edited by
                            #15

                            I started to learn Qt from "this":http://qt-project.org/doc/qt-5/tutorials-addressbook.html tutorial.
                            Try it.

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                            • C Offline
                              C Offline
                              clochydd
                              wrote on last edited by
                              #16

                              That is a good tutorial and you may find the Qt Examples here:
                              Qt Creator -> Welcome -> Examples
                              Happy coding :)

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                              • K Offline
                                K Offline
                                Kurdman
                                wrote on last edited by
                                #17

                                Thank you all very much. I try to read that tut. You are awesome guys* ;)*

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