Added new private API for Android and onPause/onResume

On Android the foreground activity can get onPause/onResume
calls. In Nfc code in android we need to know if we are paused
or resumed. And we need to make sure to call disableForegroundDispatch
inside the onPause call and in the main Ui thread. The current
implementiton of applicationStateChanged was not sufficient to
acomplish that.

This patch adds a way to receive those onPause/onResume calls in Qt
with proper timing.

Change-Id: I3a8cec093fc02ec42cc8677dfe2d0d4f8a227f8b
Reviewed-by: BogDan Vatra <bogdan@kde.org>

src/corelib/kernel/qjnihelpers.cpp

@@ -122,6 +122,45 @@ void QtAndroidPrivate::handleNewIntent(JNIEnv *env, jobject intent)
     }
 }
 
+namespace {
+    class ResumePauseListeners
+    {
+    public:
+        QMutex mutex;
+        QList<QtAndroidPrivate::ResumePauseListener *> listeners;
+    };
+}
+
+Q_GLOBAL_STATIC(ResumePauseListeners, g_resumePauseListeners)
+
+void QtAndroidPrivate::registerResumePauseListener(ResumePauseListener *listener)
+{
+    QMutexLocker locker(&g_resumePauseListeners()->mutex);
+    g_resumePauseListeners()->listeners.append(listener);
+}
+
+void QtAndroidPrivate::unregisterResumePauseListener(ResumePauseListener *listener)
+{
+    QMutexLocker locker(&g_resumePauseListeners()->mutex);
+    g_resumePauseListeners()->listeners.removeAll(listener);
+}
+
+void QtAndroidPrivate::handlePause()
+{
+    QMutexLocker locker(&g_resumePauseListeners()->mutex);
+    const QList<QtAndroidPrivate::ResumePauseListener *> &listeners = g_resumePauseListeners()->listeners;
+    for (int i=0; i<listeners.size(); ++i)
+        listeners.at(i)->handlePause();
+}
+
+void QtAndroidPrivate::handleResume()
+{
+    QMutexLocker locker(&g_resumePauseListeners()->mutex);
+    const QList<QtAndroidPrivate::ResumePauseListener *> &listeners = g_resumePauseListeners()->listeners;
+    for (int i=0; i<listeners.size(); ++i)
+        listeners.at(i)->handleResume();
+}
+
 static inline bool exceptionCheck(JNIEnv *env)
 {
     if (env->ExceptionCheck()) {

src/corelib/kernel/qjnihelpers_p.h

@@ -68,6 +68,14 @@ namespace QtAndroidPrivate
         virtual bool handleNewIntent(JNIEnv *env, jobject intent) = 0;
     };
 
+    class Q_CORE_EXPORT ResumePauseListener
+    {
+    public:
+        virtual ~ResumePauseListener() {}
+        virtual void handlePause() {};
+        virtual void handleResume() {};
+    };
+
     Q_CORE_EXPORT jobject activity();
     Q_CORE_EXPORT JavaVM *javaVM();
     Q_CORE_EXPORT jint initJNI(JavaVM *vm, JNIEnv *env);
@@ -82,6 +90,11 @@ namespace QtAndroidPrivate
     Q_CORE_EXPORT void handleNewIntent(JNIEnv *env, jobject intent);
     Q_CORE_EXPORT void registerNewIntentListener(NewIntentListener *listener);
     Q_CORE_EXPORT void unregisterNewIntentListener(NewIntentListener *listener);
+
+    Q_CORE_EXPORT void handlePause();
+    Q_CORE_EXPORT void handleResume();
+    Q_CORE_EXPORT void registerResumePauseListener(ResumePauseListener *listener);
+    Q_CORE_EXPORT void unregisterResumePauseListener(ResumePauseListener *listener);
 }
 
 QT_END_NAMESPACE

src/plugins/platforms/android/androidjnimain.cpp

@@ -594,6 +594,11 @@ static void updateApplicationState(JNIEnv */*env*/, jobject /*thiz*/, jint state
         return;
     }
 
+    if (state == Qt::ApplicationActive)
+        QtAndroidPrivate::handleResume();
+    else if (state == Qt::ApplicationInactive)
+        QtAndroidPrivate::handlePause();
+
     if (state <= Qt::ApplicationInactive) {
         // Don't send timers and sockets events anymore if we are going to hide all windows
         QAndroidEventDispatcherStopper::instance()->goingToStop(true);