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OverviewFelgo 3 Support (Qt 5) › how to select files from android native file dialog? (Qt and android question)

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  • #23540


    (I have already post this question on the Qt forum but still no answer, so I will try here)

    How other Felgo/Qt users have solved this issue? I haven’t able to find a solution for this, the most I have been able to get is the URI but I can’t find a way of how to transform it to a real path.

    I have read some android documentation following some posts like this https://stackoverflow.com/questions/15079406/qt-necessitas-reasonable-qfiledialog-replacement-skin?answertab=active#tab-top and https://stackoverflow.com/questions/3401579/get-filename-and-path-from-uri-from-mediastore/51227392#51227392 and looks like is a different method depending on the android versions and device.

    For example the code on the first post:

     QAndroidJniObject cursor = contentResolver.callObjectMethod("query", "(Landroid/net/Uri;[Ljava/lang/String;Ljava/lang/String;[Ljava/lang/String;Ljava/lang/String;)Landroid/database/Cursor;", uri.object<jobject>(), 0, 0, 0, 0);
    QAndroidJniObject DATA = QAndroidJniObject::fromString("_data");
        jint columnIndex = cursor.callMethod<jint>("getColumnIndexOrThrow", "(Ljava/lang/String;)I", DATA.object<jstring>());
        cursor.callMethod<jboolean>("moveToFirst", "()Z");
    QAndroidJniObject result = cursor.callObjectMethod("getString", "(I)Ljava/lang/String;", columnIndex);
     return result.isValid() ? result.toString() : QString();


    crash my app on my device since it returns a null when is trying to query throught the cursor, according to some posts is because the parameter ‘_data’ dosen’t exist in some devices and versions.

    I have also find this java file: https://gist.github.com/tatocaster/32aad15f6e0c50311626

    but when I call the method to access this java class using:

    QAndroidJniObject::callStaticObjectMethod (...)


    is getting me an empty string  I even created a simple java test method and always return an empty string:


    // myfile.cpp
    QAndroidJniObject jniFullPath =  QAndroidJniObject::callStaticObjectMethod(
                                "com/iubo/app/utils/FilePath" // class name
                                , "getFilePath" // method name
                                , "(Ljava/lang/String)Ljava/lang/String;" // signature
                                , jniUri.object<jstring>() ); //Uri object
    qDebug() << "realpath: " << jniFullPath.toString(). // I expected "URI:"  + the uri but returns empty
    //Java method:
    public static String getFilePath(String uriPath){
        String realPath = "URI:" + uriPath;
        return realPath;


    So in conclusion, looks that using JNI depends on android versions AND devices , and using the methods to communicate with java files aren’t working how https://doc.qt.io/qt-5/qandroidjniobject.html#details said it should work.

    how should I solve this?






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