ios - Programmatically using constraints on a button that is also programmatically made -


i'm trying facebook login button (top center of screenshot) below "register or login button" using constraints, i'm not sure constraints use , how use them. i'm quite new swift 3 , have not done constraint programmatically yet, welcomed! used x , y position in cgrect place button, noticed on different device, button not in same place, i'm trying use constraints now.

it looks this:

enter image description here

this code regarding button in viewdidload:

let fbloginbutton = fbsdkloginbutton()  view.addsubview(fbloginbutton)  fbloginbutton.frame = cgrect(x: 0, y: 0, width: view.frame.width -          100, height: 40)  self.view.addsubview(fbloginbutton)  fbloginbutton.center.x = view.frame.width/2

i tried doing:

let verticalspace = nslayoutconstraint(     item: self, attribute: .bottom, relatedby: .equal, toitem: fbloginbutton,     attribute: .bottom, multiplier: 0.75, constant: 0)

but led me error:

constraint items must each instance of uiview, or uilayoutguide.

try code had added button "send" programatically below button "show alert" added using storyboard

@iboutlet weak var showalertbutton: uibutton!  func addbutton(){       let sendbutton = uibutton(type: .system)     sendbutton.settitle("send", for: uicontrolstate())     sendbutton.translatesautoresizingmaskintoconstraints = false     self.view.addsubview(sendbutton)      sendbutton.leftanchor.constraint(equalto: showalertbutton.leftanchor, constant: 0).isactive = true     sendbutton.rightanchor.constraint(equalto: showalertbutton.rightanchor, constant: 0).isactive = true     sendbutton.topanchor.constraint(equalto: showalertbutton.bottomanchor, constant: 10).isactive = true     sendbutton.widthanchor.constraint(equaltoconstant: 80).isactive = true     sendbutton.heightanchor.constraint(equalto: showalertbutton.heightanchor).isactive = true   }

enter image description here


Comments

Post a Comment

Popular posts from this blog

Is there a better way to structure post methods in Class Based Views -

i'm using class based views in django , never specify url in ajax calls , omit action parameter in form because know these requests go through post method of class based view. notice view - profile page make many requests depending on user updating on page - post method become convoluted , if/else mess example: def post(self, request, *args, **kwargs): # handle user changing available date if request.post.get('availabledate') != none: self.updateavailabledate(request) return jsonresponse({'result':'success'}) if request.post.get('newprojectname') != none: creative_user = creativeuserprofile.objects.get(id = request.user.id) project = project.create_project(creative_user, request.post['newprojectname']) project.save() return jsonresponse({'projectid': project.id }) if request.post.get('projectimage') != none , request.files['file']: proj...
Read more

performance - Why is XCHG reg, reg a 3 micro-op instruction on modern Intel architectures? -

i'm doing micro-optimization on performance critical part of code , came across sequence of instructions (in at&t syntax): add %rax, %rbx mov %rdx, %rax mov %rbx, %rdx i thought had use case xchg allow me shave instruction , write: add %rbx, %rax xchg %rax, %rdx however, dimay found agner fog's instruction tables , xchg 3 micro-op instruction 2 cycle latency on sandy bridge, ivy bridge, broadwell, haswell , skylake. 3 whole micro-ops , 2 cycles of latency! 3 micro-ops throws off 4-1-1-1 cadence , 2 cycle latency makes worse original in best case since last 2 instructions in original might execute in parallel. now... cpu might breaking instruction micro-ops equivalent to: mov %rax, %tmp mov %rdx, %rax mov %tmp, %rdx where tmp anonymous internal register , suppose last 2 micro-ops run in parallel latency 2 cycles. given register renaming occurs on these micro-architectures, though, doesn't make sense me done way. why wouldn't register renamer ...
Read more

c# - Asp.net web api : redirect unauthorized requst to forbidden page -

im trying redirect unauthorized request forbidden page instead i'm getting forbidden page in response body , how can fix ? here's startup class : app.createperowincontext(storecontext.create); app.createperowincontext<applicationusermanager>(applicationusermanager.create); app.createperowincontext<applicationsigninmanager>(applicationsigninmanager.create); app.usecookieauthentication(new cookieauthenticationoptions { authenticationtype = defaultauthenticationtypes.applicationcookie, expiretimespan = timespan.fromdays(30), }); app.useexternalsignincookie(defaultauthenticationtypes.externalcookie); app.usetwofactorsignincookie(defaultauthenticationtypes.twofactorcookie, timespan.fromminutes(5)); app.usetwofactorrememberbrowsercookie(defaultauthenticationtypes.twofactorrememberbrowsercookie); the method im trying reach : [httpget] [authorize(roles = "admin")] public string getcurrentusername() { return userman...
Read more