iOS: Simplify view management in QIOSKeyboardListener

We don't need to keep track of the view-controller or add ourselves as
a gesture recognizer inside QIOSKeyboardListener. In fact, leaving the
call to removeGestureRecognizer in [QIOSKeyboardListener dealloc] will
result in QIOSKeyboardListener never being released, as the view that
we add the recognizer to will keep a strong reference to the recognizer,
so dealloc is never called unless the view is also released, which is
unlikely to happen. We now fully control the lifetime of the recognizer.

Change-Id: I6755e8cdfcc8f1062314db51aa54a2b7ecd1b967
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@theqtcompany.com>

4 files changed, 48 insertions, 31 deletions

diff --git a/src/plugins/platforms/ios/qiosinputcontext.h b/src/plugins/platforms/ios/qiosinputcontext.h
index 174c44751c..eb6b04a2ac 100644
--- a/src/plugins/platforms/ios/qiosinputcontext.h
+++ b/src/plugins/platforms/ios/qiosinputcontext.h
@@ -91,6 +91,8 @@ public:
     static QIOSInputContext *instance();
 
 private:
+    UIView* scrollableRootView();
+
     union {
         QIOSKeyboardListener *m_keyboardHideGesture;
         id <KeyboardState> m_keyboardState;
diff --git a/src/plugins/platforms/ios/qiosinputcontext.mm b/src/plugins/platforms/ios/qiosinputcontext.mm
index 72437fea6e..49eff2b88a 100644
--- a/src/plugins/platforms/ios/qiosinputcontext.mm
+++ b/src/plugins/platforms/ios/qiosinputcontext.mm
@@ -45,6 +45,7 @@
 
 #include "qiosglobal.h"
 #include "qiosintegration.h"
+#include "qiosscreen.h"
 #include "qiostextresponder.h"
 #include "qiosviewcontroller.h"
 #include "qioswindow.h"
@@ -76,8 +77,6 @@ static QUIView *focusView()
 // -------------------------------------------------------------------------
 
 @interface QIOSKeyboardListener : UIGestureRecognizer <KeyboardState, UIGestureRecognizerDelegate> {
-  @public
-    UIViewController *m_viewController;
   @private
     QIOSInputContext *m_context;
 }
@@ -97,26 +96,13 @@ static QUIView *focusView()
 {
     if (self = [super initWithTarget:self action:@selector(gestureStateChanged:)]) {
         m_context = context;
-        m_viewController = 0;
-
-        if (isQtApplication()) {
-            // Get the root view controller that is on the same screen as the keyboard:
-            for (UIWindow *uiWindow in [[UIApplication sharedApplication] windows]) {
-                if (uiWindow.screen == [UIScreen mainScreen]) {
-                    m_viewController = [uiWindow.rootViewController retain];
-                    break;
-                }
-            }
-            Q_ASSERT(m_viewController);
-
-            // Attach 'hide keyboard' gesture to the window, but keep it disabled when the
-            // keyboard is not visible.
-            self.enabled = NO;
-            self.cancelsTouchesInView = NO;
-            self.delaysTouchesEnded = NO;
-            [m_viewController.view.window addGestureRecognizer:self];
-        }
 
+        // UIGestureRecognizer
+        self.enabled = NO;
+        self.cancelsTouchesInView = NO;
+        self.delaysTouchesEnded = NO;
+
+        /// KeyboardState
         self.keyboardVisible = NO;
         self.keyboardVisibleAndDocked = NO;
         self.animationDuration = 0;
@@ -141,9 +127,6 @@ static QUIView *focusView()
 
 - (void)dealloc
 {
-    [m_viewController.view.window removeGestureRecognizer:self];
-    [m_viewController release];
-
     [[NSNotificationCenter defaultCenter]
         removeObserver:self
         name:@"UIKeyboardWillShowNotification" object:nil];
@@ -247,7 +230,7 @@ static QUIView *focusView()
     if (self.state != UIGestureRecognizerStatePossible)
         return;
 
-    CGPoint touchPoint = [[touches anyObject] locationInView:m_viewController.view.window];
+    CGPoint touchPoint = [[touches anyObject] locationInView:self.view];
     if (CGRectContainsPoint(self.keyboardEndRect, touchPoint))
         self.state = UIGestureRecognizerStateBegan;
 }
@@ -349,14 +332,21 @@ QIOSInputContext::QIOSInputContext()
     , m_keyboardHideGesture([[QIOSKeyboardListener alloc] initWithQIOSInputContext:this])
     , m_textResponder(0)
 {
-    if (isQtApplication())
+    if (isQtApplication()) {
+        QIOSScreen *iosScreen = static_cast<QIOSScreen*>(QGuiApplication::primaryScreen()->handle());
+        [iosScreen->uiWindow() addGestureRecognizer:m_keyboardHideGesture];
+
         connect(qGuiApp->inputMethod(), &QInputMethod::cursorRectangleChanged, this, &QIOSInputContext::cursorRectangleChanged);
+    }
+
     connect(qGuiApp, &QGuiApplication::focusWindowChanged, this, &QIOSInputContext::focusWindowChanged);
 }
 
 QIOSInputContext::~QIOSInputContext()
 {
+    [m_keyboardHideGesture.view removeGestureRecognizer:m_keyboardHideGesture];
     [m_keyboardHideGesture release];
+
     [m_textResponder release];
 }
 
@@ -398,6 +388,8 @@ QRectF QIOSInputContext::keyboardRect() const
     return m_keyboardState.keyboardRect;
 }
 
+// -------------------------------------------------------------------------
+
 void QIOSInputContext::cursorRectangleChanged()
 {
     if (!m_keyboardState.keyboardVisibleAndDocked || !qApp->focusObject())
@@ -415,6 +407,18 @@ void QIOSInputContext::cursorRectangleChanged()
     prevCursor = cursor;
 }
 
+UIView *QIOSInputContext::scrollableRootView()
+{
+    if (!m_keyboardHideGesture.view)
+        return 0;
+
+    UIWindow *window = static_cast<UIWindow*>(m_keyboardHideGesture.view);
+    if (![window.rootViewController isKindOfClass:[QIOSViewController class]])
+        return 0;
+
+    return window.rootViewController.view;
+}
+
 void QIOSInputContext::scrollToCursor()
 {
     if (!isQtApplication())
@@ -427,24 +431,29 @@ void QIOSInputContext::scrollToCursor()
         return;
     }
 
-    UIView *view = m_keyboardHideGesture->m_viewController.view;
-    if (view.window != focusView().window)
+    UIView *rootView = scrollableRootView();
+    if (!rootView)
+        return;
+
+    if (rootView.window != focusView().window)
         return;
 
     const int margin = 20;
     QRectF translatedCursorPos = qApp->inputMethod()->cursorRectangle();
     translatedCursorPos.translate(focusView().qwindow->geometry().topLeft());
 
-    qreal keyboardY = [view convertRect:m_keyboardState.keyboardEndRect fromView:nil].origin.y;
+    qreal keyboardY = [rootView convertRect:m_keyboardState.keyboardEndRect fromView:nil].origin.y;
     int statusBarY = qGuiApp->primaryScreen()->availableGeometry().y();
 
     scroll((translatedCursorPos.bottomLeft().y() < keyboardY - margin) ? 0
-        : qMin(view.bounds.size.height - keyboardY, translatedCursorPos.y() - statusBarY - margin));
+        : qMin(rootView.bounds.size.height - keyboardY, translatedCursorPos.y() - statusBarY - margin));
 }
 
 void QIOSInputContext::scroll(int y)
 {
-    UIView *rootView = m_keyboardHideGesture->m_viewController.view;
+    UIView *rootView = scrollableRootView();
+    if (!rootView)
+        return;
 
     CATransform3D translationTransform = CATransform3DMakeTranslation(0.0, -y, 0.0);
     if (CATransform3DEqualToTransform(translationTransform, rootView.layer.sublayerTransform))
diff --git a/src/plugins/platforms/ios/qiosscreen.h b/src/plugins/platforms/ios/qiosscreen.h
index 7987ef82d5..7aa62b9190 100644
--- a/src/plugins/platforms/ios/qiosscreen.h
+++ b/src/plugins/platforms/ios/qiosscreen.h
@@ -63,6 +63,7 @@ public:
     void setOrientationUpdateMask(Qt::ScreenOrientations mask);
 
     UIScreen *uiScreen() const;
+    UIWindow *uiWindow() const;
 
     void updateProperties();
 
diff --git a/src/plugins/platforms/ios/qiosscreen.mm b/src/plugins/platforms/ios/qiosscreen.mm
index e70b369b79..4af2a4965f 100644
--- a/src/plugins/platforms/ios/qiosscreen.mm
+++ b/src/plugins/platforms/ios/qiosscreen.mm
@@ -321,6 +321,11 @@ UIScreen *QIOSScreen::uiScreen() const
     return m_uiScreen;
 }
 
+UIWindow *QIOSScreen::uiWindow() const
+{
+    return m_uiWindow;
+}
+
 #include "moc_qiosscreen.cpp"
 
 QT_END_NAMESPACE