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Create a plugins

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  • Z Offline
    Z Offline
    ZapB
    wrote on last edited by
    #7

    Well for a start the 1st project needs to have
    @
    TEMPLATE = lib
    @
    rather than "app" since you are trying to make a plugin which is a shared library.

    Nokia Certified Qt Specialist
    Interested in hearing about Qt related work

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    • G Offline
      G Offline
      goli
      wrote on last edited by
      #8

      now i got this error:
      The process could not be started: The system cannot find the file specified. - for the line:
      @DESTDIR = lib

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      • Z Offline
        Z Offline
        ZapB
        wrote on last edited by
        #9

        What process? Can you post your 2 projects please? Either that or be alot more descriptive in what you are doing. You are not giving us enough information to understand what the problem is.

        You will not be able to execute your 1st project since that will just be a plugin library not an application.

        Nokia Certified Qt Specialist
        Interested in hearing about Qt related work

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        • G Offline
          G Offline
          goli
          wrote on last edited by
          #10

          1st project:

          operanditem.h

          @ #if defined(MY_NGWIDGETS_LIBRARY)

          define MYSHARED_EXPORT Q_DECL_EXPORT

          #else

          define MYSHARED_EXPORT Q_DECL_IMPORT

          #endif

          class MYSHARED_EXPORT OperandItem : public QObject
          {.....}@

          main.c

          @qmlRegisterType<OperandItem> (“Operands”, 1, 0, “MYOperand”);@

          pro file

          @QT += core gui
          QT += declarative
          QT += network
          QT += xml

          TARGET = NGWidgets
          TEMPLATE = lib
          DEFINES += MY_NGWIDGETS_LIBRARY
          CONFIG += qt plugin
          DESTDIR = lib
          OBJECTS_DIR = tmp
          MOC_DIR = tmp

          SOURCES +=
          main.cpp \
          Operands/operanditem.cpp
          HEADERS +=
          Operands/operanditem.h

          @

          2nd project:

          in some qml file i write:

          @ import QtQuick 1.0
          import Operands 1.0

          Rectangle{
          MYOperand{}
          }@

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          • L Offline
            L Offline
            lgeyer
            wrote on last edited by
            #11

            You better append your second .pro file too.

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            • Z Offline
              Z Offline
              ZapB
              wrote on last edited by
              #12

              Please have another read through this "article":http://developer.qt.nokia.com/doc/qt-4.7/declarative-tutorials-extending-chapter6-plugins.html#id-8c522ec4-43c2-4344-a4a4-148efcc18b7d and you'll see that you also need to write a plugin class derived from QDeclarativeExtensionPlugin that your 2nd project's QML engine will call the registerTypes() function of in order to register them with your 2nd project.

              This plugin class seems to be completely missing from you 1st project.

              Nokia Certified Qt Specialist
              Interested in hearing about Qt related work

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              • G Offline
                G Offline
                goli
                wrote on last edited by
                #13

                i have this class inherit from QDeclarativeExtensionPlugin and create the plugin.
                i don't know what i need to add to the 2nd project (in the pro file) to make it work with the new module...

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                • Z Offline
                  Z Offline
                  ZapB
                  wrote on last edited by
                  #14

                  You need to edit the qmldir file in your 2nd project so that it points at the path where the plugin library from your 1st project is located.

                  Nokia Certified Qt Specialist
                  Interested in hearing about Qt related work

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                  • G Offline
                    G Offline
                    goli
                    wrote on last edited by
                    #15

                    the dll file was created in the build-desktop directory(in the debug) and not in the QtCreator\lib\ directory... even when i copy the dll to this place it does not work

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                    • G Offline
                      G Offline
                      goli
                      wrote on last edited by
                      #16

                      in the pro file i write:

                      @QTPLUGIN += NGWidgets
                      LIBS += -L"C:/Qt/Projects/NGWidgets-build-desktop/debug"
                      LIBS += -lNGWidgets@

                      in the folder "C:/Qt/Projects/NGWidgets-build-desktop/debug"
                      i have the dll (NGWidgets.dll)

                      but i got the error:
                      :-1: error: cannot find -lngwidgetsd
                      collect2: ld returned 1 exit status

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                      • Z Offline
                        Z Offline
                        ZapB
                        wrote on last edited by
                        #17

                        I don't think that your 2nd project's .pro file needs to mention the NGWidgets plugin lib at all. The qmldir file tells the QDeclarativeEngine where it can dllopen your plugin library from.

                        Also the error message you posted does not match the .pro file you have posted the error message is referring to ngwidgetsd.dll whereas the .pro file mentions NGWidgets.dll (not the trailing d).

                        In your 1st project (the plugin one) make sure you are using the Q_EXPORT_PLUGIN2 macro as is mentioned in the docs:

                        @
                        Q_EXPORT_PLUGIN2( NGWidgets, NGWidgetsPlugin )
                        @

                        where I have assumed that your plugin class (the one derived from QDeclarativeExtensionPlugin) is called NGWidgetsPlugin (since you have not shown it to us).

                        Try using a qmldir file for your 2d project that looks like this:

                        @
                        plugin NGWidgets C:/Qt/Projects/NGWidgets-build-desktop/debug
                        @

                        and in your .qml file using

                        @
                        import NGWidgets 1.0
                        @

                        Nokia Certified Qt Specialist
                        Interested in hearing about Qt related work

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                        • G Offline
                          G Offline
                          goli
                          wrote on last edited by
                          #18

                          that exaclly what i did - and i create alse qmldir file in the first project (as shown in the example)....

                          in this link : http://doc.qt.nokia.com/latest/plugins-howto.html
                          they say that the pro file of the 2nd project should be changed...

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                          • Z Offline
                            Z Offline
                            ZapB
                            wrote on last edited by
                            #19

                            I do not see anything in that document relating to qml plugins. Rather than this constant back and forth can you provide a zip file of your two projects that we can try to fix up for you please?

                            Nokia Certified Qt Specialist
                            Interested in hearing about Qt related work

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                            • G Offline
                              G Offline
                              goli
                              wrote on last edited by
                              #20

                              i can't post all my code. but this is the main classes:

                              1st project :

                              ngwidgetsplugin.h

                              @#include <QDeclarativeExtensionPlugin>

                              class NGWidgetsPlugin: public QDeclarativeExtensionPlugin
                              {
                              Q_OBJECT
                              public:
                              void registerTypes(const char *uri);
                              };@

                              ngwidgetsplugin.cpp

                              @#include <QtDeclarative>
                              #include <QtPlugin>
                              //.....more includes for files

                              void NGWidgetsPlugin::registerTypes(const char *uri)
                              {
                              qmlRegisterType<OperandItem> (uri, 1, 0, "MYOperand");

                                 //................. 
                              

                              }

                              Q_EXPORT_PLUGIN2(NGWidgets, NGWidgetsPlugin)@

                              .pro

                              @QT += core gui
                              QT += declarative
                              QT += network

                              #TARGET = NGWidgets
                              TEMPLATE = lib
                              CONFIG += qt plugin
                              DESTDIR = lib
                              OBJECTS_DIR = tmp
                              MOC_DIR = tmp

                              SOURCES += ...
                              HEADERS += ...
                              OTHER_FILES += ...
                              @

                              qmldir

                              @plugin NGWidgets lib@

                              2nd project - use the plugin

                              .pro

                              @QT += core gui
                              QT += declarative
                              QT += network

                              SOURCES += ...
                              HEADERS += ...
                              OTHER_FILES += ...@

                              qmldir

                              @plugin NGWidgets C:/Qt/Projects/NGWidgets-build-desktop/debug @

                              app.qml

                              @import QtQuick 1.0
                              import NGWidgets 1.0

                              Rectangle
                              {
                              MYOperand{...}
                              }

                              @

                              i got the error : module "NGWidgets" is not installed
                              for line 2

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                              • L Offline
                                L Offline
                                lgeyer
                                wrote on last edited by
                                #21

                                Be also aware that you usually cannot mix release and debug code.

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                                • G Offline
                                  G Offline
                                  goli
                                  wrote on last edited by
                                  #22

                                  so how can i connect to the plugin, that locate in the debug dir?

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                                  • L Offline
                                    L Offline
                                    lgeyer
                                    wrote on last edited by
                                    #23

                                    I just wanted to point out that if you compile your application in debug mode you should compile your plugins in debug mode too (same goes for release builds).

                                    However - have you tried to "trace the module import":http://developer.qt.nokia.com/doc/qt-4.7/qdeclarativedebugging.html?

                                    EDIT: Are you sure that path in your qmldir file is correct? You instruct qmake to place your library in a "lib" directory but your path points to the "debug" directory. -As far as I have understood the documentation you do not need both - the qmldir and the import statement. You can omit one.-

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                                    • G Offline
                                      G Offline
                                      goli
                                      wrote on last edited by
                                      #24

                                      yes, i give the path to the location of NGWidgets.dll , and this dll is locate in the debug dir of the plugin project and also in the lib directory (in 2 cases it's not recognize the "module")...

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                                      • L Offline
                                        L Offline
                                        lgeyer
                                        wrote on last edited by
                                        #25

                                        The .dll in your debug directory is most likely an outdated version, as all new versions are moved to the lib directory (as specified as DESTDIR in the .pro file). You are pointing to the wrong directory in your qmldir file.

                                        Have you already tried tracing the module import?

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                                        • G Offline
                                          G Offline
                                          goli
                                          wrote on last edited by
                                          #26

                                          ok - you right , i changed it to :
                                          @plugin NGWidgets C:/Qt/Projects/NGWidgets-build-desktop/lib@
                                          but still have the same problem

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