[Interest] Dynamic translations for mobile apps at runtime?

[Jason H]

Sounds like there should be a qApp->translations() that we can use to remove all currently installed translations? Without it, we have to do what you do. 


> Sent: Tuesday, March 08, 2016 at 3:44 PM
> From: Gianluca <gmaxera at gmail.com>
> To: "Jason H" <jhihn at gmx.com>
> Cc: "interest at qt-project.org" <interest at qt-project.org>
> Subject: Re: [Interest] Dynamic translations for mobile apps at runtime?
>
> qApp->installTranslator add a new translation into the stack. Does not remove the old ones.
> So, if the user click 10 times: Italian - English - Italian - English … etc…
> you got ten translator into the memory.
> That’s because the translation is searched into the order on which the translator are installed into the stack.
> 
> That’s why I remove everything so there is only one translators at time into the memory.
> 
> Il giorno 08/mar/2016, alle ore 18:46, Jason H <jhihn at gmx.com> ha scritto:
> 
> > I'm wondering why you load all those languages and then remove all but one of them? Being a mobile app, I have to be somewhat conscience of memory foot print. Do you see anything wrong with:
> > 
> > void Backend::selectLanguage( QString language ) {
> >    translator = new QTranslator(this);
> >    translator->load( language, commonPath()+"/translations" );
> >    qApp->installTranslator(translator);
> > }
> > 
> > ?
> > 
> > 
> >> Hello Jason,
> >> I got the same issue some times ago … and I found that it’s possible to use the translation feature of Qt … that seems static, but it’s not.
> >> And localize.biz it’s a wonderful site that allow you to modify Qt translation files directly on web and download the updated one.
> >> 
> >> The trick to achieve (summarized) is the following:
> >> Somewhere in your code maintain and update from remote an array of Translators:
> >> 	translators["en"] = new QTranslator(this);
> >> 	translators["en"]->load( "tr_en", commonPath()+"/translations" );
> >> 	translators["de"] = new QTranslator(this);
> >> 	translators["de"]->load( "tr_de", commonPath()+"/translations" );
> >> 	translators["fr"] = new QTranslator(this);
> >> 	translators["fr"]->load( "tr_fr", commonPath()+"/translations" );
> >> 	translators["ru"] = new QTranslator(this);
> >> 	translators["ru"]->load( "tr_ru", commonPath()+"/translations" );
> >> You can change these entry with new files downloaded at runtime.
> >> 
> >> Then you implement a method that you call at runtime for changing the translator, something like that:
> >> 
> >> void Backend::selectLanguage( QString language ) {
> >> 	foreach( QString lang, translators.keys() ) {
> >> 		if ( lang == language ) {
> >> 			qApp->installTranslator( translators[lang] );
> >> 		} else {
> >> 			qApp->removeTranslator( translators[lang] );
> >> 		}
> >> 	}
> >> 	this->language = language;
> >> 	emit languageChanged();
> >> }
> >> And then there is the final trick:
> >> You create a “fake” property that is always an empty string but it’s binded to languageChanged signal:
> >> 
> >> Q_PROPERTY( QString es READ getES NOTIFY languageChanged )
> >> 
> >> And (the most annoying part), append this empty string to all string you want to change at runtime like that:
> >> 
> >> qsTr("NEWS<br/>HUB")+backend.es
> >> 
> >> And close the loop.
> >> 
> >> What will happen is the following: the translator change at runtime and you trigger a languageChanged that trigger an update of all string that got backend.es appended that trigger the call of qsTr that take the new translation from the new translator.
> >> 
> 
>