Add language setting

src/settingsdialog.cpp

@@ -129,11 +129,30 @@ SettingsDialog::SettingsDialog(QWidget *parent) : QDialog(parent)
             delete item;
     });
 
+    m_lang = new QComboBox(this);
+    m_lang->addItems({"English", "Français", "Slovenčina", "Português"});
+    QString lang;
+    switch(QLocale().language())
+    {
+    default:
+    case QLocale::English: lang = "en"; break;
+    case QLocale::French: lang = "fr"; break;
+    case QLocale::Slovak: lang = "sk"; break;
+    case QLocale::Portuguese: lang = "pt_BR"; break;
+    }
+
+    lang = settings.value("settings/lang", lang).toString();
+    if(lang == "en")m_lang->setCurrentIndex(0);
+    else if(lang == "fr")m_lang->setCurrentIndex(1);
+    else if(lang == "sk")m_lang->setCurrentIndex(2);
+    else if(lang == "pt_BR")m_lang->setCurrentIndex(3);
+
     layout->addRow(tr("Image preload count"), m_preloadImages);
     layout->addRow(tr("Thumbnails size"), m_thumSize);
     layout->addRow(tr("Saturation"), m_saturation);
     layout->addRow(tr("Slideshow interval"), m_slideShowTime);
     layout->addRow(tr("Image interpolation"), m_filtering);
+    layout->addRow(tr("Language"), m_lang);
     layout->addRow(m_qualityThumbnail);
     layout->addRow(m_useNativeDialog);
     layout->addRow(m_bestFit);
@@ -150,7 +169,6 @@ SettingsDialog::SettingsDialog(QWidget *parent) : QDialog(parent)
 #endif
     //layout->addRow(new QLabel(tr("Changes in settings will take effect after program restart.")));
 
-
     QDialogButtonBox *buttonBox = new QDialogButtonBox(this);
     buttonBox->setStandardButtons(QDialogButtonBox::Ok | QDialogButtonBox::Cancel);
     connect(buttonBox, &QDialogButtonBox::accepted, this, &QDialog::accept);
@@ -237,4 +255,14 @@ void SettingsDialog::saveSettings()
     }
     settings.setValue("settings/headerhighlightkeywords", headerHighlight.keys());
     settings.setValue("settings/headerhighlightcolors", colors);
+    QString lang;
+    int langIdx = m_lang->currentIndex();
+    switch(langIdx)
+    {
+    case 0: lang = "en"; break;
+    case 1: lang = "fr"; break;
+    case 2: lang = "sk"; break;
+    case 3: lang = "pt_BR"; break;
+    }
+    settings.setValue("settings/lang", lang);
 }