qml: add language selection to qeconfig.py/Preferences

electrum/gui/qml/components/Preferences.qml

@@ -46,7 +46,20 @@ Pane {
 
                     ElComboBox {
                         id: language
-                        enabled: false
+                        textRole: 'text'
+                        valueRole: 'value'
+                        model: Config.languagesAvailable
+                        onCurrentValueChanged: {
+                            if (activeFocus) {
+                                if (Config.language != currentValue) {
+                                    Config.language = currentValue
+                                    var dialog = app.messageDialog.createObject(app, {
+                                        text: qsTr('Please restart Electrum to activate the new GUI settings')
+                                    })
+                                    dialog.open()
+                                }
+                            }
+                        }
                     }
 
                     Label {
@@ -355,6 +368,7 @@ Pane {
     }
 
     Component.onCompleted: {
+        language.currentIndex = language.indexOfValue(Config.language)
         baseUnit.currentIndex = _baseunits.indexOf(Config.baseUnit)
         thousands.checked = Config.thousandsSeparator
         currencies.currentIndex = currencies.indexOfValue(Daemon.fx.fiatCurrency)

electrum/gui/qml/qeconfig.py

@@ -2,6 +2,7 @@ from PyQt5.QtCore import pyqtProperty, pyqtSignal, pyqtSlot, QObject
 
 from decimal import Decimal
 
+from electrum.i18n import set_language, languages
 from electrum.logging import get_logger
 from electrum.util import DECIMAL_POINT_DEFAULT, format_satoshis
 from electrum.invoices import PR_DEFAULT_EXPIRATION_WHEN_CREATING
@@ -16,6 +17,25 @@ class QEConfig(AuthMixin, QObject):
         super().__init__(parent)
         self.config = config
 
+    languageChanged = pyqtSignal()
+    @pyqtProperty(str, notify=languageChanged)
+    def language(self):
+        return self.config.get('language')
+
+    @language.setter
+    def language(self, language):
+        if language not in languages:
+            return
+        if self.config.get('language') != language:
+            self.config.set_key('language', language)
+            set_language(language)
+            self.languageChanged.emit()
+
+    languagesChanged = pyqtSignal()
+    @pyqtProperty('QVariantList', notify=languagesChanged)
+    def languagesAvailable(self):
+        return list(map(lambda x: {'value': x[0], 'text': x[1]}, languages.items()))
+
     autoConnectChanged = pyqtSignal()
     @pyqtProperty(bool, notify=autoConnectChanged)
     def autoConnect(self):