Getting reference to the top-most view window in iOS application

Question

I m creating a reusable framework for displaying notifications in an iOS application  I d like the notification views to be added over the top of everything else in the application  sort of like a UIAlertView  When I init the manager that listens for NSNotification events and adds views in response  I need to get a reference to the top-most view in the application  This is what I have at the moment    topView       UIApplication sharedApplication  keyWindow  subviews  lastObject     Would this work for any iOS application or is their a safer better way to get the top view

User · Answer

There are two parts of the problem  Top window  top view on top window   All the existing answers missed the top window part  But   UIApplication sharedApplication  keyWindow  is not guaranteed to be the top window    Top window  It is very unlikely that there will be two windows with the same windowLevel coexist for an app  so we can sort all the windows by windowLevel and get the topmost one   UIWindow  topWindow      UIApplication sharedApplication  windows sortedArrayUsingComparator  NSComparisonResult UIWindow  win1  UIWindow  win2        return win1 windowLevel - win2 windowLevel     lastObject    Top view on top window  Just to be complete  As already pointed out in the question   UIView  topView     topWindow subviews  lastObject

User · Answer

Whenever I want to display some overlay on top of everything else  I just add it on top of the Application Window directly      UIApplication sharedApplication  keyWindow  addSubview someView

User · Answer

If you are adding a loading view  an activity indicator view for instance   make sure you have an object of UIWindow class  If you show an action sheet just before you show your loading view  the keyWindow will be the UIActionSheet and not UIWindow  And since the action sheet will go away  the loading view will go away with it  Or that s what was causing me problems   UIWindow  keyWindow     UIApplication sharedApplication  keyWindow   if    NSStringFromClass  keyWindow class   isEqualToString   UIWindow             find uiwindow in windows     NSArray  windows    UIApplication sharedApplication  windows      for  UIWindow  window in windows            if   NSStringFromClass  window class   isEqualToString   UIWindow                  keyWindow   window              break

User · Answer

Usually that will give you the top view  but there s no guarantee that it s visible to the user  It could be off the screen  have an alpha of 0 0  or could be have size of 0x0 for example   It could also be that the keyWindow has no subviews  so you should probably test for that first  This would be unusual  but it s not impossible   UIWindow is a subclass of UIView  so if you want to make sure your notification is visible to the user  you can add it directly to the keyWindow using addSubview  and it will instantly be the top most view  I m not sure if this is what you re looking to do though   Based on your question  it looks like you already know this

User · Answer

I m sticking to the question as the title states and not the discussion  Which view is top visible on any given point     implementation UIView  Extra   -  UIView   findTopMostViewForPoint  CGPoint point       for int i   self subviews count - 1  i  gt   0  i--                UIView  subview    self subviews objectAtIndex i           if  subview hidden  amp  amp  CGRectContainsPoint subview frame  point                         CGPoint pointConverted    self convertPoint point toView subview               return  subview findTopMostViewForPoint pointConverted                        return self     -  UIWindow   topmostWindow       UIWindow  topWindow      UIApplication sharedApplication  windows sortedArrayUsingComparator  NSComparisonResult UIWindow  win1  UIWindow  win2            return win1 windowLevel - win2 windowLevel         lastObject       return topWindow      end   Can be used directly with any UIWindow as receiver or any UIView as receiver

User · Answer

Just use this code if you want to add a view above of everything in the screen     UIApplication sharedApplication  keyWindow addSubView  yourView

User · Answer

try this  UIWindow  window      UIApplication sharedApplication  windows  lastObject

User · Answer

Actually there could be more than one UIWindow in your application  For example  if a keyboard is on screen then   UIApplication sharedApplication  windows  will contain at least two windows  your key-window and the keyboard window    So if you want your view to appear ontop of both of them then you gotta do something like       UIApplication sharedApplication  windows  lastObject  addSubview view      Assuming lastObject contains the window with the highest windowLevel priority

User · Answer

If your application only works in portrait orientation  this is enough      UIApplication sharedApplication  keyWindow  addSubview yourView    And your view will not be shown over keyboard and status bar   If you want to get a topmost view that over keyboard or status bar  or you want the topmost view can rotate correctly with devices  please try this framework   https   github com HarrisonXi TopmostView  It supports iOS7 8 9

User · Answer

UIWindow  keyWindow     UIApplication sharedApplication  keyWindow   if    NSStringFromClass  keyWindow class   isEqualToString   UIWindow           NSArray  windows    UIApplication sharedApplication  windows      for  UIWindow  window in windows            if   NSStringFromClass  window class   isEqualToString   UIWindow                  keyWindow   window              break

[objective-c] Getting reference to the top-most view/window in iOS application

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