Qt tr() not working if i am using in static member

[sysrules]

#1 Please let me know why it is not working i am new in Qt. here is the code

@
#include <QApplication>
#include <QPushButton>
#include <QTranslator>
class Transl
{
Q_OBJECT
public:
static const QString str;
};
const QString Transl::str = QObject::tr("Hello world");
// const char* const gstr = "Hello World";

int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QTranslator translator;
translator.load("trans_la");
app.installTranslator(&translator);

QPushButton *button =    new QPushButton();
button->setText(Transl::str);
// button->setText(tr(gstr));   // This is also throw error "error: ‘tr’ was not declared in this scope"
button->resize(100,100);
button->show()
return app.exec();

}@

My trans_la.ts file contains this which i generate by lupdate.

@<TS version="2.0">
<context>
<name>QObject</name>
<message>
<location filename="main.cpp" line="10"/>
<source>Hello world</source>
<translation>Orbis, te saluto!</translation>
</message>
</context>
</TS> @

Then I do lrelease which generate trans_la.qm. But when i run my executable instead of showing the translated string it shows "Hello world". Please suggest me why it is not working.

#2 Also if you see i have commented two lines(11th and 22nd) where I am trying to use with constant char* global variable where it thows error tr() was not declared in the scope.

[dasun]

Qt tr does not work on static constant members. use QT_TR_NOOP instead tr.

@const QString Transl::str = QT_TR_NOOP("Hello world");@

[sysrules]

hi @dasun i tried QT_TR_NOOP("Hello world") in that case lupdate is not working it ask tr is not working without any context. Please help :). Also can you figure out about the error of #2 why tr() is giving me error ?

[dasun]

Main function is not an QObject. tr defined in QObject.

You can use @QObject::tr("Hello World");@

[SGaist]

Hi and welcome to devnet,

IIRC, for static text like that it's QT_TRANSLATE_NOOP that should be used

[sysrules]

Hi @SGalst what actually QT_TRANSLATE_NOOP will do ? will it work on translation ?

[SGaist]

A little search in the documentation would have returned the "explanation":http://qt-project.org/doc/qt-4.8/linguist-programmers.html#using-qt-tr-noop-and-qt-translate-noop

[sysrules]

hey thanks for the valuable info. but i still did not find the solution of #2 why it is giving me error. well i'll try to look more in documentation. Thanks

[SGaist]

It simple: tr is a method of QObject and main is a function not a QObject