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qFile doesn't open on iOS

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  • K kgregory

    I'm using QFile to read and write files on my mobile app as below.

    QFile myFile("myfile.txt");
    if (myFile.open(QIODevice::ReadOnly)) {
        //read stuff
        myFile.close();
    } else {
        qDebug() << "File open failed.";
    }
    

    This works ok in Android, but in iOS, it doesn't work. Is there something I need to put in my Info.plist file to enable this or is there some other reason why this wouldn't work on iOS?

    ekkescornerE Offline
    ekkescornerE Offline
    ekkescorner
    Qt Champions 2016
    wrote on last edited by
    #3

    @kgregory I'm storing my app datafiles here:

        // Android: HomeLocation works, iOS: not writable
        // Android: AppDataLocation works out of the box, iOS you must create the DIR first !!
        myPath = QStandardPaths::standardLocations(QStandardPaths::AppDataLocation).value(0);
    

    attention: on iOS you must create the directory where on Android it exists already
    I'm always creating a /data folder at AppDataLocation to store my files in

    ekke ... Qt Champion 2016 | 2024 ... mobile business apps
    5.15 --> 6.9 https://t1p.de/ekkeChecklist
    QMake --> CMake https://t1p.de/ekkeCMakeMobileApps

    K J.HilkJ 2 Replies Last reply
    4
    • ekkescornerE ekkescorner

      @kgregory I'm storing my app datafiles here:

          // Android: HomeLocation works, iOS: not writable
          // Android: AppDataLocation works out of the box, iOS you must create the DIR first !!
          myPath = QStandardPaths::standardLocations(QStandardPaths::AppDataLocation).value(0);
      

      attention: on iOS you must create the directory where on Android it exists already
      I'm always creating a /data folder at AppDataLocation to store my files in

      K Offline
      K Offline
      kgregory
      wrote on last edited by
      #4

      @ekkescorner

      So will myPath (in your example) be a directory specific to my application or is it a general folder that all of the applications use?

      1 Reply Last reply
      0
      • SGaistS Offline
        SGaistS Offline
        SGaist
        Lifetime Qt Champion
        wrote on last edited by
        #5

        AppDataLocation is only for your application.

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

          Thanks! Here's the code I have now. It appears to be working, although I don't have my bluetooth device handy right now which prevents me from fully testing it.

          QString m_dataLocation = QStandardPaths::standardLocations(QStandardPaths::AppDataLocation).value(0);
              if (QDir(m_dataLocation).exists()) {
                  qDebug() << "App data directory exists. " << m_dataLocation;
              } else {
                  if (QDir("").mkpath(m_dataLocation)) {
                      qDebug() << "Created app data directory. " << m_dataLocation;
                  } else {
                      qDebug() << "Failed to create app data directory. " << m_dataLocation;
                  }
              }
          
          QFile myFile(m_dataLocation + "/myfile.txt");
          if (myFile.open(QIODevice::ReadOnly)) {
              //read stuff
              myFile.close();
          } else {
              qDebug() << "File open failed.";
          }
          
          ekkescornerE 1 Reply Last reply
          0
          • K kgregory

            Thanks! Here's the code I have now. It appears to be working, although I don't have my bluetooth device handy right now which prevents me from fully testing it.

            QString m_dataLocation = QStandardPaths::standardLocations(QStandardPaths::AppDataLocation).value(0);
                if (QDir(m_dataLocation).exists()) {
                    qDebug() << "App data directory exists. " << m_dataLocation;
                } else {
                    if (QDir("").mkpath(m_dataLocation)) {
                        qDebug() << "Created app data directory. " << m_dataLocation;
                    } else {
                        qDebug() << "Failed to create app data directory. " << m_dataLocation;
                    }
                }
            
            QFile myFile(m_dataLocation + "/myfile.txt");
            if (myFile.open(QIODevice::ReadOnly)) {
                //read stuff
                myFile.close();
            } else {
                qDebug() << "File open failed.";
            }
            
            ekkescornerE Offline
            ekkescornerE Offline
            ekkescorner
            Qt Champions 2016
            wrote on last edited by
            #7

            @kgregory great to hear that it works for you.

            ekke ... Qt Champion 2016 | 2024 ... mobile business apps
            5.15 --> 6.9 https://t1p.de/ekkeChecklist
            QMake --> CMake https://t1p.de/ekkeCMakeMobileApps

            1 Reply Last reply
            0
            • ekkescornerE ekkescorner

              @kgregory I'm storing my app datafiles here:

                  // Android: HomeLocation works, iOS: not writable
                  // Android: AppDataLocation works out of the box, iOS you must create the DIR first !!
                  myPath = QStandardPaths::standardLocations(QStandardPaths::AppDataLocation).value(0);
              

              attention: on iOS you must create the directory where on Android it exists already
              I'm always creating a /data folder at AppDataLocation to store my files in

              J.HilkJ Offline
              J.HilkJ Offline
              J.Hilk
              Moderators
              wrote on last edited by
              #8

              @ekkescorner said in qFile doesn't open on iOS:

              @kgregory I'm storing my app datafiles here:

                  // Android: HomeLocation works, iOS: not writable
                  // Android: AppDataLocation works out of the box, iOS you must create the DIR first !!
                  myPath = QStandardPaths::standardLocations(QStandardPaths::AppDataLocation).value(0);
              

              attention: on iOS you must create the directory where on Android it exists already
              I'm always creating a /data folder at AppDataLocation to store my files in

              This, should really be in the documentation, right here
              I spend way to much time on this, thanks @ekkescorner !


              Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


              Q: What's that?
              A: It's blue light.
              Q: What does it do?
              A: It turns blue.

              1 Reply Last reply
              1
              • SGaistS Offline
                SGaistS Offline
                SGaist
                Lifetime Qt Champion
                wrote on last edited by
                #9

                @J-Hilk Patches for the documentation are also welcomed ;-)

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

                J.HilkJ 1 Reply Last reply
                0
                • SGaistS SGaist

                  @J-Hilk Patches for the documentation are also welcomed ;-)

                  J.HilkJ Offline
                  J.HilkJ Offline
                  J.Hilk
                  Moderators
                  wrote on last edited by
                  #10

                  @SGaist
                  :D
                  sure, but honestly I wouldn't know where to start, is there a dokumentaion/guide for it?
                  It's not that the docs are a wiki and just anyone con click on edit in the upper right corner.


                  Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                  Q: What's that?
                  A: It's blue light.
                  Q: What does it do?
                  A: It turns blue.

                  aha_1980A 1 Reply Last reply
                  0
                  • J.HilkJ J.Hilk

                    @SGaist
                    :D
                    sure, but honestly I wouldn't know where to start, is there a dokumentaion/guide for it?
                    It's not that the docs are a wiki and just anyone con click on edit in the upper right corner.

                    aha_1980A Offline
                    aha_1980A Offline
                    aha_1980
                    Lifetime Qt Champion
                    wrote on last edited by
                    #11

                    @J.Hilk

                    You might want to look at https://wiki.qt.io/Gerrit_Introduction

                    Qt has to stay free or it will die.

                    1 Reply Last reply
                    1
                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #12

                      It's all in the source Luke ! ^^

                      Most of the documentation is written in the sources themselves or in .doc files. Here you just need a clone of qtbase then edit qstandardpaths.cpp. When in doubt about the location of a piece of documentation I just run grep or ag on the source with one of the phrase to get the right file to edit.

                      As for setting up your environment for submission, you have a detailed getting started guide here.

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

                      raven-worxR 1 Reply Last reply
                      2
                      • SGaistS SGaist

                        It's all in the source Luke ! ^^

                        Most of the documentation is written in the sources themselves or in .doc files. Here you just need a clone of qtbase then edit qstandardpaths.cpp. When in doubt about the location of a piece of documentation I just run grep or ag on the source with one of the phrase to get the right file to edit.

                        As for setting up your environment for submission, you have a detailed getting started guide here.

                        raven-worxR Offline
                        raven-worxR Offline
                        raven-worx
                        Moderators
                        wrote on last edited by
                        #13

                        @SGaist said in qFile doesn't open on iOS:

                        It's all in the source Luke ! ^^

                        may the source be with you! :)

                        --- SUPPORT REQUESTS VIA CHAT WILL BE IGNORED ---
                        If you have a question please use the forum so others can benefit from the solution in the future

                        1 Reply Last reply
                        0
                        • J.HilkJ Offline
                          J.HilkJ Offline
                          J.Hilk
                          Moderators
                          wrote on last edited by
                          #14

                          I'll like to add some additional informations, that I encountered, in case someone comes onto this thread.

                          On Ios, since iOS 8.0, the absolute Path actually changes with each recompile/update.

                          That means, if you store the absolute path somewhere, e.g in your settings, and you recompile your appliaction, you won't find the file again.

                          This however does not mean, the file got deleted. It is still at QStandardPaths::standardLocations(QStandardPaths::AppDataLocation)

                          So instead of storing the absolute path, store the ´filename+extension´ and the enum QStandardPaths::StandardLocation and reconstruct the path from there.


                          Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                          Q: What's that?
                          A: It's blue light.
                          Q: What does it do?
                          A: It turns blue.

                          1 Reply Last reply
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