Android: QtActivityDelegateBase listens to focus events from child views

In order to detect gaining/losing and moving focus between windows,
implement GlobalFocusChangeListener for the root View.

Add a surfaceFocusChanged native function in QAndroidPlatformWindow in
order to follow these focus changes.

Task-number: QTBUG-118139
Pick-to: 6.7
Change-Id: Ia9bf6249c28a420f42793a9829aef31b12757630
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>

2 files changed, 21 insertions, 1 deletions

diff --git a/src/plugins/platforms/android/qandroidplatformwindow.cpp b/src/plugins/platforms/android/qandroidplatformwindow.cpp
index 289884020e..e4d7b4c7ec 100644
--- a/src/plugins/platforms/android/qandroidplatformwindow.cpp
+++ b/src/plugins/platforms/android/qandroidplatformwindow.cpp
@@ -342,10 +342,28 @@ void QAndroidPlatformWindow::setSurface(JNIEnv *env, jobject object, jint window
     }
 }
 
+void QAndroidPlatformWindow::windowFocusChanged(JNIEnv *env, jobject object,
+                                          jboolean focus, jint windowId)
+{
+    Q_UNUSED(env)
+    Q_UNUSED(object)
+    QWindow* window = QtAndroid::windowFromId(windowId);
+    Q_ASSERT_X(window, "QAndroidPlatformWindow", "windowFocusChanged event window should exist");
+    if (focus) {
+        QWindowSystemInterface::handleFocusWindowChanged(window);
+    } else if (!focus && window == qGuiApp->focusWindow()) {
+        // Clear focus if current window has lost focus
+        QWindowSystemInterface::handleFocusWindowChanged(nullptr);
+    }
+}
+
 bool QAndroidPlatformWindow::registerNatives(QJniEnvironment &env)
 {
     if (!env.registerNativeMethods(QtJniTypes::Traits<QtJniTypes::QtWindow>::className(),
-                                  {Q_JNI_NATIVE_SCOPED_METHOD(setSurface, QAndroidPlatformWindow)})) {
+                                {
+                                    Q_JNI_NATIVE_SCOPED_METHOD(setSurface, QAndroidPlatformWindow),
+                                    Q_JNI_NATIVE_SCOPED_METHOD(windowFocusChanged, QAndroidPlatformWindow)
+                                })) {
         qCCritical(lcQpaWindow) << "RegisterNatives failed for"
                                 << QtJniTypes::Traits<QtJniTypes::QtWindow>::className();
         return false;
diff --git a/src/plugins/platforms/android/qandroidplatformwindow.h b/src/plugins/platforms/android/qandroidplatformwindow.h
index 1896316bf6..3f1e8ac992 100644
--- a/src/plugins/platforms/android/qandroidplatformwindow.h
+++ b/src/plugins/platforms/android/qandroidplatformwindow.h
@@ -93,6 +93,8 @@ protected:
 private:
     static void setSurface(JNIEnv *env, jobject obj, jint windowId, QtJniTypes::Surface surface);
     Q_DECLARE_JNI_NATIVE_METHOD_IN_CURRENT_SCOPE(setSurface)
+    static void windowFocusChanged(JNIEnv *env, jobject object, jboolean focus, jint windowId);
+    Q_DECLARE_JNI_NATIVE_METHOD_IN_CURRENT_SCOPE(windowFocusChanged)
 };
 
 QT_END_NAMESPACE