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POChange zoomScale and contentOffset of UIScrollView in UIApplicationStateBackground state
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Id
15604276
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
6
CommunityOwnedDate
CreationDate
2013-03-24T21:33:32.877
FavoriteCount
3
LastActivityDate
2013-04-10T12:45:54.350
LastEditDate
2013-04-10T12:45:54.350
LastEditorUserId
1983667
OwnerUserId
1983667
ParentId
0
PostTypeId
1
Score
1
ViewCount
387
LastEditorDisplayName
text
Body
I know it's not recommended to change any view appearance when the application is moved to background state, but for my specific task I cannot postpone this activity and I really like to complete it in a couple of seconds after the user hits the home button. That's what I do: I load a webpage in a UIWebView and after loading completion I change the contentOffset and zoomScale in order to make a specific screenshot of that webpage. When the app is in active application state everything works fine. Now I wanted to add some more multitasking capabilities. I encapsulated the above described webpage loading and rendering activity in a protected background task (iOS Task Completion), in order to complete it even when the user hits the home button. I have noticed that the page loading and the rendering of the webpage screenshot (with the renderInContext: method) works just fine in background, BUT it seems that the webview (i.e. the encapsulated UIScrollView instance) does not react on setContentOffset: and setZoomScale: messages as soon as the app is in background.. So I'm asking you if you know any alternatives to change the content offset / zoomscale? (modifications directly on CALayer?) Or any method to "force" the scrollview to perform the content changes even in background. PS: On the iOS simulator everything works fine even in application background state, but on real devices it does not. EDIT: I have created a simple demo project that demonstrates the issue. You can download it here (please read the instructions in the zip file): <a href="http://dl.dropbox.com/u/3556271/BackgroundBugDemo.zip" rel="nofollow">http://dl.dropbox.com/u/3556271/BackgroundBugDemo.zip</a> I appreciate every hint or tip. Thanks!
Tags
<ios><uiview><uiwebview><uiscrollview><uikit>
Title
Change zoomScale and contentOffset of UIScrollView in UIApplicationStateBackground state
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