iOS: use an explicit pointer to qiosViewController

As it stood, we always relied on the root view controller
being a QIOSViewController if isQtApplication() returned
true. For mixed application, this might not always be true
as native code can choose to replace the root view controller
at times, or even rip it out, and place it as a child of
another (e.g UISplitViewController).
This change will give an extra protection against that.

Change-Id: I0cb85796a8b82f9037c32f9e85e04e1dc7aad8e2
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>

src/plugins/platforms/ios/qiosapplicationdelegate.h

@@ -42,9 +42,12 @@
 #import <UIKit/UIKit.h>
 #import <QtGui/QtGui>
 
+#import "qiosviewcontroller.h"
+
 @interface QIOSApplicationDelegate : UIResponder <UIApplicationDelegate>
 
 @property (strong, nonatomic) UIWindow *window;
+@property (strong, nonatomic) QIOSViewController *qiosViewController;
 
 @end
 

src/plugins/platforms/ios/qiosapplicationdelegate.mm

@@ -46,6 +46,7 @@
 @implementation QIOSApplicationDelegate
 
 @synthesize window;
+@synthesize qiosViewController;
 
 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
 {
@@ -85,6 +86,7 @@
 
 - (void)dealloc
 {
+    [qiosViewController release];
     [window release];
     [super dealloc];
 }

src/plugins/platforms/ios/qiosglobal.h

@@ -52,7 +52,7 @@ QT_BEGIN_NAMESPACE
 class QPlatformScreen;
 
 bool isQtApplication();
-QIOSViewController *rootViewController();
+QIOSViewController *qiosViewController();
 
 CGRect toCGRect(const QRect &rect);
 QRect fromCGRect(const CGRect &rect);

src/plugins/platforms/ios/qiosglobal.mm

@@ -58,10 +58,14 @@ bool isQtApplication()
     return isQt;
 }
 
-QIOSViewController *rootViewController()
+QIOSViewController *qiosViewController()
 {
+    // If Qt controls the application, we have created a root view controller were we place top-level
+    // QWindows. Note that in a mixed native application, our view controller might later be removed or
+    // added as a child of another controller. To protect against that, we keep an explicit pointer to the
+    // view controller in cases where this is the controller we need to access.
     static QIOSViewController *c = isQtApplication() ?
-        static_cast<QIOSViewController *>([UIApplication sharedApplication].delegate.window.rootViewController) : nil;
+        static_cast<QIOSApplicationDelegate *>([UIApplication sharedApplication].delegate).qiosViewController : nil;
     return c;
 }
 

src/plugins/platforms/ios/qiosscreen.mm

@@ -142,7 +142,7 @@ QIOSScreen::QIOSScreen(unsigned int screenIndex)
 
     if (isQtApplication()) {
         // When in a non-mixed environment, let QScreen follow the current interface orientation:
-        setPrimaryOrientation(toQtScreenOrientation(UIDeviceOrientation(rootViewController().interfaceOrientation)));
+        setPrimaryOrientation(toQtScreenOrientation(UIDeviceOrientation(qiosViewController().interfaceOrientation)));
     }
 
     [pool release];

src/plugins/platforms/ios/qioswindow.mm

@@ -375,7 +375,7 @@ void QIOSWindow::setVisible(bool visible)
         requestActivateWindow();
     } else {
         // Activate top-most visible QWindow:
-        NSArray *subviews = rootViewController().view.subviews;
+        NSArray *subviews = qiosViewController().view.subviews;
         for (int i = int(subviews.count) - 1; i >= 0; --i) {
             UIView *view = [subviews objectAtIndex:i];
             if (!view.hidden) {
@@ -431,7 +431,7 @@ void QIOSWindow::setParent(const QPlatformWindow *parentWindow)
         UIView *parentView = reinterpret_cast<UIView *>(parentWindow->winId());
         [parentView addSubview:m_view];
     } else if (isQtApplication()) {
-        [rootViewController().view addSubview:m_view];
+        [qiosViewController().view addSubview:m_view];
     }
 }
 

src/plugins/platforms/ios/qtmain.mm

@@ -56,7 +56,8 @@ extern int qt_main(int argc, char *argv[]);
 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
 {
     self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
-    self.window.rootViewController = [[[QIOSViewController alloc] init] autorelease];
+    self.qiosViewController = [[[QIOSViewController alloc] init] autorelease];
+    self.window.rootViewController = self.qiosViewController;
 
 #ifdef QT_DEBUG
     self.window.backgroundColor = [UIColor cyanColor];