Add Language menu to select the UI language. Closes #9

src/main.cpp

@@ -94,42 +94,34 @@ int showErrorUpdatingTheDB()
 
 void loadTranslations(QApplication &app, QTranslator &myappTranslator)
 {
-    // Detect UI language.
-    // On macOS, QLocale::system().name() returns the regional-format locale
-    // (e.g. "en_US") which may differ from the display language set in
-    // System Preferences. uiLanguages() reads AppleLanguages and is
-    // reliable on all platforms.
-    QString language;
-    QStringList uiLangs = QLocale::system().uiLanguages();
-    if (!uiLangs.isEmpty())
-        language = uiLangs.first().left(2).toLower();
-    else
-        language = QLocale::system().name().left(2).toLower();
+    Utilities util(Q_FUNC_INFO);
+
+    // The user may have selected a fixed language in the Language menu.
+    // "auto" (the default) follows the operating system language.
+    QSettings settings(util.getCfgFile(), QSettings::IniFormat);
+    QString language = settings.value("Language", "auto").toString().toLower();
+
+    if ((language == "auto") || language.isEmpty())
+    {
+        // Detect UI language.
+        // On macOS, QLocale::system().name() returns the regional-format locale
+        // (e.g. "en_US") which may differ from the display language set in
+        // System Preferences. uiLanguages() reads AppleLanguages and is
+        // reliable on all platforms.
+        QStringList uiLangs = QLocale::system().uiLanguages();
+        if (!uiLangs.isEmpty())
+            language = uiLangs.first().left(2).toLower();
+        else
+            language = QLocale::system().name().left(2).toLower();
+    }
 
    //qDebug() << Q_FUNC_INFO << "Language:" << language;
 
     if (language == "en")
         return; // English is built-in; no translation file needed.
 
     QString fileName = "klog_" + language + ".qm";
-    QStringList searchPaths;
-
-#if defined(Q_OS_MACOS)
-    // .app bundle: KLog.app/Contents/Resources/translations/
-    // (CMakeLists: MACOSX_PACKAGE_LOCATION Resources/translations)
-    searchPaths << QCoreApplication::applicationDirPath() + "/../Resources/translations";
-#elif defined(Q_OS_WIN)
-    // Alongside the .exe (CMakeLists: DESTINATION translations)
-    searchPaths << QCoreApplication::applicationDirPath() + "/translations";
-#else
-    // Linux FHS (CMakeLists: DESTINATION ${CMAKE_INSTALL_DATADIR}/klog/translations)
-    searchPaths << QCoreApplication::applicationDirPath() + "/../share/klog/translations";
-    searchPaths << "/usr/share/klog/translations";
-    searchPaths << "/usr/local/share/klog/translations";
-#endif
-    // Fallback for development builds on every platform
-    searchPaths << QCoreApplication::applicationDirPath() + "/translations";
-    searchPaths << QCoreApplication::applicationDirPath() + "/../src/translations";
+    const QStringList searchPaths = util.getTranslationSearchPaths();
 
     for (const QString &dir : searchPaths)
     {

src/setuppages/setuppageuserdata.cpp

@@ -67,7 +67,22 @@
    provinceLineEdit = new QLineEdit;
    countryLineEdit = new QLineEdit;
 
+   languageComboBox = new QComboBox;
+   languageComboBox->addItem(tr("System default"), "auto");
+   const QStringList languages = util->getAvailableLanguages();
+   for (const QString &code : languages)
+   {
+       QLocale langLocale(code);
+       QString langName = langLocale.nativeLanguageName();
+       if (langName.isEmpty())
+           langName = code;
+       else
+           langName[0] = langName.at(0).toUpper();
+       languageComboBox->addItem(langName, code);
+   }
+
    nameLineEdit->setToolTip(tr("Enter your name."));
+   languageComboBox->setToolTip(tr("Select the language of the KLog user interface. 'System default' uses the language of the operating system."));
    address1LineEdit->setToolTip(tr("Enter your address - 1st line."));
    address2LineEdit->setToolTip(tr("Enter your address - 2nd line."));
    address3LineEdit->setToolTip(tr("Enter your address - 3rd line."));
@@ -78,13 +93,15 @@
    countryLineEdit->setToolTip(tr("Enter your country."));
 
    QLabel *nameLabel = new QLabel(tr("&Name"));
+   QLabel *languageLabel = new QLabel(tr("Lang&uage"));
    QLabel *addressLabel = new QLabel(tr("&Address"));
    QLabel *cityLabel = new QLabel(tr("Cit&y"));
    QLabel *zipLabel = new QLabel(tr("&Zip Code"));
    QLabel *provLabel = new QLabel(tr("Pro&v/State"));
    QLabel *countryLabel = new QLabel(tr("Countr&y"));
 
    nameLabel->setBuddy(nameLineEdit);
+   languageLabel->setBuddy(languageComboBox);
    addressLabel->setBuddy(address1LineEdit);
    cityLabel->setBuddy(cityLineEdit);
    zipLabel->setBuddy(zipLineEdit);
@@ -98,6 +115,8 @@
 
    personalLayout->addWidget(nameLabel, 0, 0);
    personalLayout->addWidget(nameLineEdit, 1, 0);
+   personalLayout->addWidget(languageLabel, 0, 2);
+   personalLayout->addWidget(languageComboBox, 1, 2);
    personalLayout->addWidget(addressLabel, 2, 0);
    personalLayout->addWidget(address1LineEdit, 3, 0, 1, 2);
    personalLayout->addWidget(address2LineEdit, 4, 0, 1, 2);
@@ -717,6 +736,15 @@
     settings.setValue ("Antenna3",getAntenna3());
     settings.setValue ("Power", getPower ());
     settings.endGroup ();
+
+    // The language is a top level setting as it is read in main.cpp before the UI exists.
+    QString newLanguage = languageComboBox->currentData().toString();
+    if (settings.value("Language", "auto").toString().toLower() != newLanguage)
+    {
+        settings.setValue("Language", newLanguage);
+        QMessageBox::information(this, tr("KLog - Language"),
+                                 tr("The language change will take effect the next time you start KLog."));
+    }
     //qDebug() << Q_FUNC_INFO << " - END";
 }
 
@@ -748,4 +776,8 @@
     ant3LineEdit->setText (settings.value ("Antenna3").toString ());
     myPowerSpinBox->setValue(settings.value ("Power").toDouble ());
     settings.endGroup ();
+
+    // The language is a top level setting as it is read in main.cpp before the UI exists.
+    int langIndex = languageComboBox->findData(settings.value("Language", "auto").toString().toLower());
+    languageComboBox->setCurrentIndex(qMax(0, langIndex));
 }

src/setuppages/setuppageuserdata.h

@@ -132,6 +132,7 @@ private slots:
 
     //Personal Tab
     QLineEdit *nameLineEdit;
+    QComboBox *languageComboBox;
     QTextEdit *addressTextEdit;
     QLineEdit *address1LineEdit;
     QLineEdit *address2LineEdit;

src/utilities.cpp

@@ -26,6 +26,9 @@
 #include "utilities.h"
 #include "callsign.h"
 #include <QRegularExpression>
+// Qt headers are not in cppcheck's include path on the CI; silence the false positive.
+// cppcheck-suppress missingIncludeSystem
+#include <QCoreApplication>
 //bool c;
 Utilities::Utilities(const QString &_parentName)
 {
@@ -583,6 +586,49 @@ QString Utilities::getCfgFile()
 #endif
 }
 
+QStringList Utilities::getTranslationSearchPaths()
+{
+    QStringList searchPaths;
+#if defined(Q_OS_MACOS)
+    // .app bundle: KLog.app/Contents/Resources/translations/
+    // (CMakeLists: MACOSX_PACKAGE_LOCATION Resources/translations)
+    searchPaths << QCoreApplication::applicationDirPath() + "/../Resources/translations";
+#elif defined(Q_OS_WIN)
+    // Alongside the .exe (CMakeLists: DESTINATION translations)
+    searchPaths << QCoreApplication::applicationDirPath() + "/translations";
+#else
+    // Linux FHS (CMakeLists: DESTINATION ${CMAKE_INSTALL_DATADIR}/klog/translations)
+    searchPaths << QCoreApplication::applicationDirPath() + "/../share/klog/translations";
+    searchPaths << "/usr/share/klog/translations";
+    searchPaths << "/usr/local/share/klog/translations";
+#endif
+    // Fallback for development builds on every platform
+    searchPaths << QCoreApplication::applicationDirPath() + "/translations";
+    searchPaths << QCoreApplication::applicationDirPath() + "/../src/translations";
+    // qt_add_translations generates the .qm files in <build>/src in development builds
+    searchPaths << QCoreApplication::applicationDirPath() + "/../src";
+    return searchPaths;
+}
+
+QStringList Utilities::getAvailableLanguages()
+{
+    QStringList languages;
+    languages << "en"; // English is built-in; no translation file needed.
+    const QStringList paths = getTranslationSearchPaths();
+    for (const QString &dir : paths)
+    {
+        const QStringList files = QDir(dir).entryList(QStringList("klog_*.qm"), QDir::Files);
+        for (const QString &file : files)
+        {   // klog_<code>.qm
+            QString code = file.mid(5, file.length() - 8).toLower();
+            if (!code.isEmpty() && !languages.contains(code))
+                languages << code;
+        }
+    }
+    languages.sort();
+    return languages;
+}
+
 QString Utilities::getDebugLogFile()
 {
 #if defined(Q_OS_WIN)

src/utilities.h

@@ -86,6 +86,8 @@ class Utilities : public QObject {
     QString getTQSLsPath();   // Depending on the OS where are usually installed the executables
     QString getHomeDir();
     QString getCfgFile();
+    QStringList getTranslationSearchPaths(); // Folders where the klog_*.qm files may be installed
+    QStringList getAvailableLanguages();     // 2-letter codes of the languages with a translation installed (plus built-in English)
     QString getCTYFile();
     QString getDebugLogFile();
     QString getSaveSpotsLogFile();