QSettings problem - doesnt save anything

[Hawk30100]

Hello there,

I've a problem with saving some values with QSettings.
I just had a look on several examples and the documentation, but my code don't want to save values.

I just tried to write a simple application to verify whether values will be saved on my android device:

@QSettings settings = new QSettings(QSettings::IniFormat, QSettings::SystemScope, "Company", "Application");
if(settings->contains("test"))
{
qDebug() << "Value from storage: " << settings->value("test");
}
else
{
qDebug() << "No key test saved!";
settings->setValue("test", 5);
settings->sync();
}@

The setting will be stored into a storage, but it will not be saved permanently on the disk.
If I run the code above twice in one running application, the value is saved and read once.

If I start the application two times with the code above (code is only called one time), the application always returns "nothing saved".

Did I made a mistake?

[SGaist]

Hi,

What version of Qt are you using on what OS ?

You do have a memory leak in your code and a typo. QSettings is generally allocated on the stack when needed, almost never on the heap.

[Hawk30100]

I am using Qt 5.2.1 on Android 4.1.2.

I didn't copied the free() into the code snippet.

Is there any reason why QSettings should not work on heap?
(I'll let my program run with a QSetting on stack and post the result here)

[Hawk30100]

Ok I just solved it. The problem was the used Scope in the Constructor.
If I use "UserScope" my program works well. With "SystemScope" it won't save anything.

Heap and stack are both working fine for me.

[SGaist]

I didn't say it would not work on the heap, just that it's not the general way to use it.

For SystemScope failing, I can't say whether it's the correct behavior or not. That might be a question for the interest mailing list.

Anyway, since you have it running now, please update the thread title prepending [solved] so other forum users may know a solution has been found :)

[Hawk30100]

Unfortunately I need now the QSettings::SystemScope option to be able to edit the ini file manually. Therefore my problem still exists.

I am just using the same code as available above.

The path of the ini file is: "/etc/xdg/Company/Application.ini"
Values will not be saved into this file and I can not access the file via terminal on the device.

(QSettings::UserScope is working fine for me.)
Problem on Google Nexus 5 (Android 4.4.2) and on my old Samsung Galaxy Tab (Android 4.1.2) with Qt 5.2 (Qt using Creator 3.0.1 & Qt Creator 3.1)

[SGaist]

If you cannot access the file from the terminal, you won't be able to it from Qt either. No read access means that only root can access this file.

[Hawk30100]

If I start my Qt Application and save a key "test" with value 5, for some reason it will be stored - temporarily.
After I saved the value, I call the value() method to read from the ini file - that works! So the application itself is able to read from a previously saved value.

If I exit / kill the application and start the application again, the ini file is no longer available and the cycle described few lines above starts again.

I don't know why the ini file is only stored temporarily.
Could someone else test my code above on his/her device?

[cezmen]

Suggestion: try using a different constructor for QSettings, combined with an appropriate writable location, just like the following code :

#include <QSettings>
#include <QStandardPaths>

QString m_path ;
QString m_filename;
QSettings * p_settings;

m_path = QStandardPaths::writableLocation(QStandardPaths::ConfigLocation) ;
m_filename = "config.ini" ;
p_settings = new QSettings(m_path + "/"+ m_filename,QSettings::IniFormat) ;

This code works for me on any platform I've tested (MacOS, iOS and Android).

[Hawk30100]

Thanks, that's working for me.

One more question: How do you access the .ini file?
I'm getting a 'permission denied' error if I try to access the file via an emulated terminal on the device.

If i use your code, the ini file will be saved to the path:
"/data/data/org.qtproject.example.textproject/files/.config/config.ini"