Add support for multilanguage

main.cpp

@@ -1,11 +1,45 @@
 #include "ui/mainwindow.h"
 
 #include <QApplication>
+#include <QSettings>
+#include <QTranslator>
+#include <QMessageBox>
+#include <QInputDialog>
 
 int main(int argc, char *argv[])
 {
     QApplication a(argc, argv);
     MainWindow w;
+    QSettings* settings = new QSettings("GUIsettings.ini", QSettings::IniFormat);
+    QVariant lang = settings->value("lang", "null");
+    if(lang == "null")
+    {
+        lang = "lang/en_US.qm";
+        QStringList langList;
+        langList.append("English");
+        langList.append("简体中文");
+        QString seletedText = QInputDialog::getItem(&w, "", "Choose a language:", langList, 0, false);
+        if(seletedText == "English")
+        {
+            lang = "lang/en_US.qm";
+        }
+        else if(seletedText == "简体中文")
+        {
+            lang = "lang/zh_CN.qm";
+        }
+    }
+    QTranslator* translator = new QTranslator(&w);
+    if(translator->load(lang.toString()))
+    {
+        a.installTranslator(translator);
+        settings->setValue("lang", lang);
+    }
+    else
+    {
+        QMessageBox::information(&w, "Error", "Can't load " + lang.toString() + " as translation file.");
+    }
+    delete settings;
+    w.initUI();
     w.show();
     return a.exec();
 }