[Qt] Use MapChangeWillStartLoadingMap to get notified about style changes

platform/qt/include/qquickmapboxglstyleproperty.hpp

@@ -28,6 +28,9 @@ public:
     void setValue(const QVariant &);
     QVariant value() const;
 
+public slots:
+    void checkUpdated();
+
 signals:
     void layerChanged(const QString &);
     void propertyChanged(const QString &);
@@ -36,7 +39,6 @@ signals:
 
 protected:
     QQuickMapboxGLStyleProperty(QQuickItem *parent, Type);
-    void checkUpdated();
 
     QVariantMap m_map;
 };

platform/qt/qmlapp/main.qml

@@ -277,6 +277,20 @@ ApplicationWindow {
                 onClicked: waterColorDialog.open()
             }
 
+            Button {
+                anchors.left: parent.left
+                anchors.right: parent.right
+                text: "Light style"
+                onClicked: { mapStreets.style = "mapbox://styles/mapbox/light-v9" }
+            }
+
+            Button {
+                anchors.left: parent.left
+                anchors.right: parent.right
+                text: "Dark style"
+                onClicked: { mapStreets.style = "mapbox://styles/mapbox/dark-v9" }
+            }
+
             CheckBox {
                 id: roadLabel
                 anchors.left: parent.left

platform/qt/src/qquickmapboxgl.cpp

@@ -23,7 +23,9 @@ QQuickMapboxGL::~QQuickMapboxGL()
 
 QQuickFramebufferObject::Renderer *QQuickMapboxGL::createRenderer() const
 {
-    return new QQuickMapboxGLRenderer();
+    QQuickMapboxGLRenderer *renderer = new QQuickMapboxGLRenderer();
+    connect(renderer, SIGNAL(styleChanged()), this, SIGNAL(styleChanged()));
+    return renderer;
 }
 
 void QQuickMapboxGL::setPlugin(QDeclarativeGeoServiceProvider *)
@@ -267,11 +269,13 @@ void QQuickMapboxGL::itemChange(QQuickItem::ItemChange change, const QQuickItem:
     case QQuickItem::ItemChildAddedChange:
         if (QQuickMapboxGLStyleProperty *property = qobject_cast<QQuickMapboxGLStyleProperty *>(value.item)) {
             connect(property, SIGNAL(updated(QVariantMap)), this, SLOT(onStylePropertyUpdated(QVariantMap)));
+            connect(this, SIGNAL(styleChanged()), property, SLOT(checkUpdated()));
         }
         break;
     case QQuickItem::ItemChildRemovedChange:
         if (QQuickMapboxGLStyleProperty *property = qobject_cast<QQuickMapboxGLStyleProperty *>(value.item)) {
             disconnect(property, SIGNAL(updated(QVariantMap)), this, SLOT(onStylePropertyUpdated(QVariantMap)));
+            disconnect(this, SIGNAL(styleChanged()), property, SLOT(checkUpdated()));
         }
     default:
         break;

platform/qt/src/qquickmapboxglrenderer.cpp

@@ -28,9 +28,24 @@ QQuickMapboxGLRenderer::~QQuickMapboxGLRenderer()
 
 void QQuickMapboxGLRenderer::onMapChanged(QMapboxGL::MapChange change)
 {
-    if (change == QMapboxGL::MapChangeDidFinishLoadingMap) {
+    auto onMapChangeWillStartLoadingMap = [&]() {
+        m_styleLoaded = false;
+    };
+
+    auto onMapChangeDidFinishLoadingMap = [&]() {
         m_styleLoaded = true;
-        update();
+        emit styleChanged();
+    };
+
+    switch (change) {
+    case QMapboxGL::MapChangeWillStartLoadingMap:
+        onMapChangeWillStartLoadingMap();
+        break;
+    case QMapboxGL::MapChangeDidFinishLoadingMap:
+        onMapChangeDidFinishLoadingMap();
+        break;
+    default:
+        break;
     }
 }
 

platform/qt/src/qquickmapboxglrenderer.hpp

@@ -25,6 +25,7 @@ public:
 
 signals:
     void centerChanged(const QGeoCoordinate &);
+    void styleChanged();
 
 public slots:
     void onMapChanged(QMapboxGL::MapChange);