Merge remote-tracking branch 'origin/5.5' into dev

Change-Id: If9fd98525b6b4ca07e5e006fc98bf372a73b8a21

1 files changed, 13 insertions, 1 deletions

diff --git a/src/plugins/platforms/android/androidjnimain.cpp b/src/plugins/platforms/android/androidjnimain.cpp
index 47018bfece..19ab051162 100644
--- a/src/plugins/platforms/android/androidjnimain.cpp
+++ b/src/plugins/platforms/android/androidjnimain.cpp
@@ -42,6 +42,7 @@
 #include "androidjniinput.h"
 #include "androidjniclipboard.h"
 #include "androidjnimenu.h"
+#include "androiddeadlockprotector.h"
 #include "qandroidplatformdialoghelpers.h"
 #include "qandroidplatformintegration.h"
 #include "qandroidassetsfileenginehandler.h"
@@ -600,11 +601,22 @@ static void updateApplicationState(JNIEnv */*env*/, jobject /*thiz*/, jint state
         QtAndroidPrivate::handlePause();
 
     if (state <= Qt::ApplicationInactive) {
+        // NOTE: sometimes we will receive two consecutive suspended notifications,
+        // In the second suspended notification, QWindowSystemInterface::flushWindowSystemEvents()
+        // will deadlock since the dispatcher has been stopped in the first suspended notification.
+        // To avoid the deadlock we simply return if we found the event dispatcher has been stopped.
+        if (QAndroidEventDispatcherStopper::instance()->stopped())
+            return;
+
         // Don't send timers and sockets events anymore if we are going to hide all windows
         QAndroidEventDispatcherStopper::instance()->goingToStop(true);
         QCoreApplication::processEvents();
         QWindowSystemInterface::handleApplicationStateChanged(Qt::ApplicationState(state));
-        QWindowSystemInterface::flushWindowSystemEvents();
+        {
+            AndroidDeadlockProtector protector;
+            if (protector.acquire())
+                QWindowSystemInterface::flushWindowSystemEvents();
+        }
         if (state == Qt::ApplicationSuspended)
             QAndroidEventDispatcherStopper::instance()->stopAll();
     } else {