change language without restart app

[nthung]

bool load=qTranslator->load("en_la"); 		
	QApplication::installTranslator(qTranslator);
	 m_UI->retranslateUi(this);

bool load=qTranslator->load("en_la"); 		
	QApplication::installTranslator(qTranslator);
	 m_UI->retranslateUi(this);

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I want an app can change language without restart app, and i coded as above.
But that code only run at fisrt correctly. but at second it is incorrect, that is mean that the language can change at the first, and from second can change language
thanks