fix bug

@@ -442,7 +442,7 @@ static float kprogressViewRadius = 2.0f;
 {
     UIViewController *result = nil;
     
-    UIWindow * window = [[UIApplication sharedApplication] keyWindow];
+    UIWindow * window = [[[UIApplication sharedApplication] delegate] window];
     if (window.windowLevel != UIWindowLevelNormal)
     {
         NSArray *windows = [[UIApplication sharedApplication] windows];