objective c - iOS autolayout vs ScrollView : Contentsize issue -


what need

i have scrollview following hierarchy :

scrollview
. ^ contentview(uiview)
. - ^ view1(yellow)
. - ^ view2(gray)

view1(yellow) has fixed height , pinned top of contentview. have specified constraints except height view2. coz adding subview view2(gray) programmatically , of random height.

the problem @ loss on how set height constraint of view2. scrollview needs have constraints running top through bottom in order calculate contentsize. height of view2 fixed after subview added, have necessary constraints determining height, of course.

what tried

1) first plan add subview , set constraints programmatically make scrollview happy. :

detailsview = [profiledetailsview instantiatefromnib]; [self.detailholder addsubview:detailsview];  [self.detailholder addconstraint:[nslayoutconstraint constraintwithitem:detailsview                                                       attribute:nslayoutattributetop                                                       relatedby:nslayoutrelationequal                                                          toitem:self.detailholder                                                       attribute:nslayoutattributetop                                                      multiplier:1.0                                                        constant:0.0]];  [self.detailholder addconstraint:[nslayoutconstraint constraintwithitem:detailsview                                                       attribute:nslayoutattributeleading                                                       relatedby:nslayoutrelationequal                                                          toitem:self.detailholder                                                       attribute:nslayoutattributeleading                                                      multiplier:1.0                                                        constant:0.0]];  [self.detailholder addconstraint:[nslayoutconstraint constraintwithitem:detailsview                                                       attribute:nslayoutattributebottom                                                       relatedby:nslayoutrelationequal                                                          toitem:self.detailholder                                                       attribute:nslayoutattributebottom                                                      multiplier:1.0                                                        constant:0.0]];  [self.detailholder addconstraint:[nslayoutconstraint constraintwithitem:detailsview                                                       attribute:nslayoutattributetrailing                                                       relatedby:nslayoutrelationequal                                                          toitem:self.detailholder                                                       attribute:nslayoutattributetrailing                                                      multiplier:1.0                                                        constant:0.0]];

the problem xcode gives me error scrollview has ambiguous scrollable content height. cannot give fixed height view2 because subview later adding have necessary constraints set scrollview's `contentsize.

2) tried adding height constraint view2 lower priority when subviews constraints kick in, height constraint overriden. doesn't seem work reason.

you can give view2 placeholder size removed @ runtime automatically make auto layout system happy

enter image description here


Comments

Post a Comment

Popular posts from this blog

html - Outlook 2010 Anchor (url/address/link) -

i'm trying link specific pdf page msoutlook'10 or msword'10, #page=... anchor particularly useful , works fine elsewhere. unfortunately when click [ctr-k] in outlook or winword, links re-formatted assuming unc path. pdf file located on shared drive. using "file:" prefix links open pdf in adobe reader (outside of browser), , "http:" open inside browser. issue seem need open in browser "file:" prefix in order anchor work. know anchors work inside browser. outlook uses windows/explorer default program (based on file extension) seems open in adobe reader neglecting anchor. is aware of solution, link specific page or bookmark of shared-pdf ms outlook and/or winword link? common references: mailermailer.com/...anchor-tags-html-emails campaignmonitor.com/...anchor-links-in-email-newsletters/ stackoverflow.com/...anchor-in-pdf-document
Read more

javascript - Why does running this loop 9 times take 100x longer than running it 8 times? -

consider code: test = function() { } t = new test(); (var = 0; < 8; i++) { result = t instanceof test; } if change number of iterations 8 9 , loop take 100 times longer complete in latest version of firefox (41.0.1). tested on 2 different pcs , magic limit 8. here jsperf test used: http://jsperf.com/instanceof-8-times-vs-9-times does have idea why might happen? seems specific instanceof . not happen if else object, example check property. note: filed bugzilla bug this. jan de mooij mozilla team has posted details in bugzilla thread . here's simplistic interpretation of highly technical answers: in i < 8 case, firefox smart enough hoist result = t instanceof test; statement out of loop (according tests, doesn't seem omit altogether). in i < 9 case, apparently doesn't optimization . why? reason not clear, related fact 9 iterations threshold above function considered "hot" enough run through jit compiler. i < 8 cas...
Read more

Getting gateway time-out Rails app with Nginx + Puma running on Digital Ocean -

following this guide setup app on digital ocean droplet, not working. site not loading , it's throwing: "gateway time-out". the puma server works, since ps aux | grep puma prints: root 15878 0.0 0.4 376832 2168 ? sl 12:50 0:00 puma 2.13.4 (unix:///var/www/myapp/shared/tmp/sockets/myapp-puma.sock) [20150930164940] root 15881 0.0 0.7 903676 3692 ? sl 12:50 0:06 puma: cluster worker 0: 15878 [20150930164940] root 24654 0.0 0.1 11748 916 pts/2 s+ 18:00 0:00 grep --color=auto puma my nginx config: user root; worker_processes 1; events { worker_connections 1024; } http { upstream puma { server unix:///var/www/myapp/shared/tmp/sockets/myapp-puma.sock; } server { listen 80; server_name myapp.com; root /var/www/myapp/current/public; access_log /var/www/myapp/current/log/access.log; error_log /...
Read more