Usage of QT_TR_NOOP()

[kichi]

Hi everybody,

I would like to know usage of QT_TR_NOOP() (not QT_TRANSLATE_NOOP()).

I use the Qt SDK 4.5.1 in Linux/X11 and work in Qt Creator 1.1.0.

I wrote a sample code as follows.

#include <QApplication>
#include <QMainWindow>
#include <QTranslator>
#include <QString>
#include <QtGlobal>
 
class MyMessage {
	Q_DECLARE_TR_FUNCTIONS(MyMessage)
public:			
	MyMessage(){}
	~MyMessage(){}
 
	static QString GetMessage() {
		static const char* message = QT_TR_NOOP("Hello");
		return QString(QObject::tr(message));
	}
};
 
int main(int argc, char *argv[])
{
	QApplication 	application(argc, argv);
	QMainWindow 	mainWindow;
	QTranslator		translator;
 
	translator.load("./MyAppMessages.qm");
	application.installTranslator(&translator);
 
	mainWindow.setWindowTitle(MyMessage::GetMessage());
	mainWindow.show();
 
	return application.exec();
}

#include <QApplication>
#include <QMainWindow>
#include <QTranslator>
#include <QString>
#include <QtGlobal>

class MyMessage {
	Q_DECLARE_TR_FUNCTIONS(MyMessage)
public:			
	MyMessage(){}
	~MyMessage(){}
	
	static QString GetMessage() {
		static const char* message = QT_TR_NOOP("Hello");
		return QString(QObject::tr(message));
	}
};

int main(int argc, char *argv[])
{
	QApplication 	application(argc, argv);
	QMainWindow 	mainWindow;
	QTranslator		translator;
	
	translator.load("./MyAppMessages.qm");
	application.installTranslator(&translator);
	
	mainWindow.setWindowTitle(MyMessage::GetMessage());
	mainWindow.show();
	
	return application.exec();
}

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And I made "MyAppMessages.qm" with lupdate, Qt Linguist, and lrelease to translate the message "Hello" into Japanese.
And I built and ran the program.
but window title was "Hello" yet.

Although I am studying English hard, my English is not great yet,
and I may make many mistakes. So, please be patient with me.

Thank you very much for any kind of help.
kichi

[wysota]

QT_TR_NOOP only marks the text as something that may need translation (so that it shows up in Linguist) but it doesn't do any translating. For that you need to use tr().

[kichi]

Thank you very much.
kichi

[kichi]

In my understanding, not only QT_TR_NOOP, but also QT_TRANSLATE_NOOP
merely marks the text for extraction.
so, I guess that "Hello" is displayed, in the following code.
but, "Hello" was translated into Japanese.
Why?

#include <QApplication>
#include <QMainWindow>
#include <QTranslator>
#include <QtGlobal>
 
static const char* greetingList[] = {
	QT_TRANSLATE_NOOP("Greeting", "Good morning"),
	QT_TRANSLATE_NOOP("Greeting", "Goodbye")
};
 
int main(int argc, char *argv[])
{
	QApplication 	application(argc, argv);
	QMainWindow 	mainWindow;
	QTranslator		translator;
 
	translator.load("./MyAppMessages.qm");
	application.installTranslator(&translator);
 
	mainWindow.setWindowTitle(application.translate("Greeting", greetingList[0]));
	mainWindow.show();
 
	return application.exec();
}

#include <QApplication>
#include <QMainWindow>
#include <QTranslator>
#include <QtGlobal>

static const char* greetingList[] = {
	QT_TRANSLATE_NOOP("Greeting", "Good morning"),
	QT_TRANSLATE_NOOP("Greeting", "Goodbye")
};

int main(int argc, char *argv[])
{
	QApplication 	application(argc, argv);
	QMainWindow 	mainWindow;
	QTranslator		translator;
	
	translator.load("./MyAppMessages.qm");
	application.installTranslator(&translator);
	
	mainWindow.setWindowTitle(application.translate("Greeting", greetingList[0]));
	mainWindow.show();
	
	return application.exec();
}

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[wysota]

Because you called QCoreApplication::translate().

[kichi]

I made a mistake.
I'm sorry.
I understand.
Thank you very much.