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Error in my first Qt5 program

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  • SGaistS SGaist

    Might be a silly question but did you check that python3 is really the one from your virtual environment ?

    M Offline
    M Offline
    Mikenitin92
    wrote on last edited by
    #9

    @SGaist I did not check. How can I check if python3 is from my virtual environment?

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    • SGaistS Offline
      SGaistS Offline
      SGaist
      Lifetime Qt Champion
      wrote on last edited by
      #10

      Run which python3 in the terminal you use to execute your script.

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      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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      • M Offline
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        Mikenitin92
        wrote on last edited by
        #11

        That gave me ~/.nitin_venv/bin/python. So, I think python is from my virtual environment. Also, Do I have to run the my python program from my virtual environment?

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        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #12

          The file doesn't need to be in there, the virtual environment is there to provide you with the dependencies you need in a controlled fashion.

          Can you show the code you are using to test that ?

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

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          • M Offline
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            Mikenitin92
            wrote on last edited by
            #13

            Sure.
            Here it is!

            from PyQt5.QtWidgets import *
            import sys
            app = QApplication([])
            label = QLabel('Hello world!')
            label.show()
            app.exec_()

            JonBJ 1 Reply Last reply
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            • M Mikenitin92

              Sure.
              Here it is!

              from PyQt5.QtWidgets import *
              import sys
              app = QApplication([])
              label = QLabel('Hello world!')
              label.show()
              app.exec_()

              JonBJ Online
              JonBJ Online
              JonB
              wrote on last edited by JonB
              #14

              @Mikenitin92
              If your problem seems to be something about not being to find libraries such that Qt apps can't be run then this probably has nothing to do with it. But I don't think you can write a Qt app to just "display a label nowhere" as per your code (you need a window or a dialog etc.). Did you get this code from somewhere/do you have a problem when it runs, or are you still at the ImportError just trying to get going?

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              • M Offline
                M Offline
                Mikenitin92
                wrote on last edited by
                #15

                Hi,

                I have tested with a new sample file which is:
                print ("Hi")
                from PyQt5.QtWidgets import *

                And this is the output:
                Hi
                Traceback (most recent call last):
                File "/Users/Nitin/PycharmProjects/pluralsight/nitin_venv/lib/test.py", line 2, in <module>
                from PyQt5.QtWidgets import *
                ImportError: dlopen(/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/PyQt5/QtWidgets.so, 2): Symbol not found: __os_activity_create
                Referenced from: /Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/PyQt5/Qt/lib/QtCore.framework/Versions/5/QtCore (which was built for Mac OS X 10.12)
                Expected in: /usr/lib/libSystem.B.dylib
                in /Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/PyQt5/Qt/lib/QtCore.framework/Versions/5/QtCore

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                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #16

                  @Mikenitin92 said in Error in my first Qt5 program:

                  import sys
                  app = QApplication([])

                  Unrelated but to be clean, it should be sys.argv as parameter of QApplication.

                  What version of PyQt do you have installed ?
                  Did you try to uninstall your system version of PyQt and re-install it in your virtual environment ?

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

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                  • M Offline
                    M Offline
                    Mikenitin92
                    wrote on last edited by
                    #17

                    Hello,

                    I have PyQt5. I have deleted the virtual folder and created it again, activated and installed PyQt5. Did I do it right?

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                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #18

                      Yes you did, however PyQt5 is the package name, not its version. However since you just now installed it, it should be the latest version available.

                      Did you also uninstall the version you have installed system wide ?

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

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                      • M Offline
                        M Offline
                        Mikenitin92
                        wrote on last edited by
                        #19

                        I don't think I have installed PyQt5 system wide. Do you know how I can check if it is installed system wide?

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                        • SGaistS Offline
                          SGaistS Offline
                          SGaist
                          Lifetime Qt Champion
                          wrote on last edited by
                          #20

                          @Mikenitin92 said in Error in my first Qt5 program:

                          /Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/PyQt5/QtWidgets.so

                          That path makes me think that it is since it's the OS provided Python framework.

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

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                          • C Offline
                            C Offline
                            cudmore
                            wrote on last edited by
                            #21

                            A bit late to answer but I just found this, have a similar error, and might be of some help. Here is my error:

                            Traceback (most recent call last):
                              File "bimpy/interface/bStackBrowser.py", line 6, in <module>
                                from PyQt5 import QtGui, QtCore, QtWidgets
                            ImportError: dlopen(/Users/cudmore/Sites/bImPy/bImPy_env/lib/python3.7/site-packages/PyQt5/QtGui.abi3.so, 2): Symbol not found: _futimens
                              Referenced from: /Users/cudmore/Sites/bImPy/bImPy_env/lib/python3.7/site-packages/PyQt5/Qt/lib/QtCore.framework/Versions/5/QtCore (which was built for Mac OS X 10.13)
                              Expected in: /usr/lib/libSystem.B.dylib
                             in /Users/cudmore/Sites/bImPy/bImPy_env/lib/python3.7/site-packages/PyQt5/Qt/lib/QtCore.framework/Versions/5/QtCore
                            

                            I am running on macOS Sierra (10.12.6) so the 'built for Mac OSX 10.13' part of the error makes sense...

                            I was able to get rid of this by downgrading PyQt from 5.14.1 to 5.13.0

                            Install a new virtual environment

                            # create a virtual environment in folder 'myenv'
                            python3 -m venv myenv
                            
                            # activate the virtual environment
                            source myenv/bin/activate 
                            

                            Check both pip and python are running rom it

                            which python
                            # returns: /Users/cudmore/Sites/bImPy/myenv/bin/python
                            which pip
                            # returns: /Users/cudmore/Sites/bImPy/myenv/bin/pip
                            

                            Install PyQt == 5.13.0

                            pip install PyQt==5.13.0
                            
                            # I also needed PyQtChart==5.13.0 with
                            pip install PyQtChart==5.13.0
                            

                            Check the version of PyQt you install

                            pip freeze | grep PyQt
                            

                            Gave me

                            PyQt5==5.13.0
                            PyQt5-sip==12.7.1
                            PyQtChart==5.13.0
                            

                            Alternatively, if you want to downgrade to PyQt==5.13.0 in an existing install, simply do

                            pip install PyQt==5.13.0 --upgrade
                            

                            If that doesn't work, first uninstall then reinstall

                            # just to be safe, first uninstall
                            pip uninstall PyQt
                            # then install specific version
                            pip install PyQt==5.13.0
                            

                            This build error is on the Qt dev end. I am needing to pay attention to this because me and my users are spread across macOS: 10.14, 10.15, 10.16, 10.17. I also have users on Windows 7/10 and this does not seem to be an issue?

                            Hope this helps...

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