Propagate the LanguageChange events from the QQuickWindow to the items

Fixes: QTBUG-78141
Task-number: QTBUG-82020
Change-Id: Id47f8efe77cd3f6bfd330c8759059e19de5a86d2
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

4 files changed, 43 insertions, 0 deletions

diff --git a/src/quick/items/qquickitem.cpp b/src/quick/items/qquickitem.cpp
index fe8df6fb64..bc68d46075 100644
--- a/src/quick/items/qquickitem.cpp
+++ b/src/quick/items/qquickitem.cpp
@@ -8254,6 +8254,10 @@ bool QQuickItem::event(QEvent *ev)
         ev->ignore();
         break;
 #endif // gestures
+    case QEvent::LanguageChange:
+        for (QQuickItem *item : d->childItems)
+            QCoreApplication::sendEvent(item, ev);
+        break;
     default:
         return QObject::event(ev);
     }
diff --git a/src/quick/items/qquickwindow.cpp b/src/quick/items/qquickwindow.cpp
index 426a30dfca..55292d2157 100644
--- a/src/quick/items/qquickwindow.cpp
+++ b/src/quick/items/qquickwindow.cpp
@@ -1767,6 +1767,10 @@ bool QQuickWindow::event(QEvent *e)
         if (d->activeFocusItem)
             QCoreApplication::sendEvent(d->activeFocusItem, e);
         return true;
+    case QEvent::LanguageChange:
+        if (d->contentItem)
+            QCoreApplication::sendEvent(d->contentItem, e);
+        break;
     default:
         break;
     }
diff --git a/tests/auto/quick/qquickitem/data/hellotr_la.qm b/tests/auto/quick/qquickitem/data/hellotr_la.qm
new file mode 100644
index 0000000000..25c0aad583
--- /dev/null
+++ b/tests/auto/quick/qquickitem/data/hellotr_la.qm
diff --git a/tests/auto/quick/qquickitem/tst_qquickitem.cpp b/tests/auto/quick/qquickitem/tst_qquickitem.cpp
index 8aab13e095..b5e001a2b7 100644
--- a/tests/auto/quick/qquickitem/tst_qquickitem.cpp
+++ b/tests/auto/quick/qquickitem/tst_qquickitem.cpp
@@ -40,6 +40,7 @@
 #include "../../shared/util.h"
 #include "../shared/viewtestutil.h"
 #include <QSignalSpy>
+#include <QTranslator>
 
 #ifdef TEST_QTBUG_60123
 #include <QWidget>
@@ -70,6 +71,7 @@ public:
     ulong timestamp;
     QPoint lastWheelEventPos;
     QPoint lastWheelEventGlobalPos;
+    int languageChangeEventCount = 0;
 protected:
     virtual void focusInEvent(QFocusEvent *) { Q_ASSERT(!focused); focused = true; }
     virtual void focusOutEvent(QFocusEvent *) { Q_ASSERT(focused); focused = false; }
@@ -86,6 +88,12 @@ protected:
         lastWheelEventPos = event->position().toPoint();
         lastWheelEventGlobalPos = event->globalPosition().toPoint();
     }
+    bool event(QEvent *e) override
+    {
+        if (e->type() == QEvent::LanguageChange)
+            languageChangeEventCount++;
+        return QQuickItem::event(e);
+    }
 };
 
 class TestWindow: public QQuickWindow
@@ -198,6 +206,7 @@ private slots:
 #endif
 
     void setParentCalledInOnWindowChanged();
+    void receivesLanguageChangeEvent();
 
 private:
 
@@ -2155,6 +2164,32 @@ void tst_qquickitem::setParentCalledInOnWindowChanged()
     QVERIFY(ensureFocus(&view)); // should not crash
 }
 
+void tst_qquickitem::receivesLanguageChangeEvent()
+{
+    QQuickWindow window;
+    window.setFramePosition(QPoint(100, 100));
+    window.resize(200, 200);
+    window.show();
+    QVERIFY(QTest::qWaitForWindowExposed(&window));
+
+    QScopedPointer<TestItem> child1(new TestItem);
+    child1->setObjectName(QStringLiteral("child1"));
+    child1->setSize(QSizeF(200, 100));
+    child1->setParentItem(window.contentItem());
+
+    QScopedPointer<TestItem> child2(new TestItem);
+    child2->setObjectName(QStringLiteral("child2"));
+    child2->setSize(QSizeF(50, 50));
+    child2->setParentItem(child1.data());
+
+    QTranslator t;
+    QVERIFY(t.load("hellotr_la.qm", dataDirectory()));
+    QVERIFY(QCoreApplication::installTranslator(&t));
+
+    QTRY_COMPARE(child1->languageChangeEventCount, 1);
+    QCOMPARE(child2->languageChangeEventCount, 1);
+}
+
 QTEST_MAIN(tst_qquickitem)
 
 #include "tst_qquickitem.moc"