Android: Avoid deadlock in Qt.inputMethod.visible

A blocking isSoftwareKeyboardVisible() is a deadlock
waiting to happen: when the android input method performs
blocking metacalls from the android thread to the GUI
thread all the time, we cannot block the GUI thread
waiting for the android thread.

Task-number: QTBUG-40750
Change-Id: I2490897b0f65e0d92214907e239b10b372d949dd
Reviewed-by: Christian Stromme <christian.stromme@digia.com>

1 files changed, 4 insertions, 12 deletions

diff --git a/src/plugins/platforms/android/androidjniinput.cpp b/src/plugins/platforms/android/androidjniinput.cpp
index cd0659227d..2c4b664487 100644
--- a/src/plugins/platforms/android/androidjniinput.cpp
+++ b/src/plugins/platforms/android/androidjniinput.cpp
@@ -59,10 +59,10 @@ namespace QtAndroidInput
     static jmethodID m_showSoftwareKeyboardMethodID = 0;
     static jmethodID m_resetSoftwareKeyboardMethodID = 0;
     static jmethodID m_hideSoftwareKeyboardMethodID = 0;
-    static jmethodID m_isSoftwareKeyboardVisibleMethodID = 0;
     static jmethodID m_updateSelectionMethodID = 0;
 
     static bool m_ignoreMouseEvents = false;
+    static bool m_softwareKeyboardVisible = false;
 
     static QList<QWindowSystemInterface::TouchPoint> m_touchPoints;
 
@@ -125,15 +125,7 @@ namespace QtAndroidInput
 
     bool isSoftwareKeyboardVisible()
     {
-        AttachedJNIEnv env;
-        if (!env.jniEnv)
-            return false;
-
-        bool visibility = env.jniEnv->CallStaticBooleanMethod(applicationClass(), m_isSoftwareKeyboardVisibleMethodID);
-#ifdef QT_DEBUG_ANDROID_IM_PROTOCOL
-        qDebug() << "@@@ ISSOFTWAREKEYBOARDVISIBLE" << visibility;
-#endif
-        return visibility;
+        return m_softwareKeyboardVisible;
     }
 
 
@@ -714,8 +706,9 @@ namespace QtAndroidInput
                                                false);
     }
 
-    static void keyboardVisibilityChanged(JNIEnv */*env*/, jobject /*thiz*/, jboolean /*visibility*/)
+    static void keyboardVisibilityChanged(JNIEnv */*env*/, jobject /*thiz*/, jboolean visibility)
     {
+        m_softwareKeyboardVisible = visibility;
         QAndroidInputContext *inputContext = QAndroidInputContext::androidInputContext();
         if (inputContext && qGuiApp)
             inputContext->emitInputPanelVisibleChanged();
@@ -756,7 +749,6 @@ namespace QtAndroidInput
         GET_AND_CHECK_STATIC_METHOD(m_showSoftwareKeyboardMethodID, appClass, "showSoftwareKeyboard", "(IIIII)V");
         GET_AND_CHECK_STATIC_METHOD(m_resetSoftwareKeyboardMethodID, appClass, "resetSoftwareKeyboard", "()V");
         GET_AND_CHECK_STATIC_METHOD(m_hideSoftwareKeyboardMethodID, appClass, "hideSoftwareKeyboard", "()V");
-        GET_AND_CHECK_STATIC_METHOD(m_isSoftwareKeyboardVisibleMethodID, appClass, "isSoftwareKeyboardVisible", "()Z");
         GET_AND_CHECK_STATIC_METHOD(m_updateSelectionMethodID, appClass, "updateSelection", "(IIII)V");
         return true;
     }