ios - UI Page View Controller Scroll Won't Scroll Backwards -


i have implemented uipageviewcontroller want able scroll infinitely right (as in user swipes left) , able scroll backwards in other direction way start. don''t want user able scroll left (as in user swipe right) on first page, though have 3 pages loop, how can this?

i have figured out how make infinite scroll 3 view controllers right ( in user scrolls left) when user tries scroll left (as in user swipes right) bugs out , screen goes white?

can improve on code user can infinitely scroll both ways, not one? , if possible prevent user scrolling backwards on first panel? thanks.

pageviewcontroller.h

#import <uikit/uikit.h>  @interface pageviewcontroller : uipageviewcontroller  <uipageviewcontrollerdelegate, uipageviewcontrollerdatasource> @end

pageviewcontroller.m

 #import "pageviewcontroller.h"  @interface pageviewcontroller ()  @end  @implementation pageviewcontroller {     nsarray *myviewcontrollers;   }  - (void)viewdidload {     [super viewdidload];      self.delegate = self;     self.datasource = self;      uiviewcontroller *p1 = [self.storyboard                             instantiateviewcontrollerwithidentifier:@"contentviewcontroller1"];     uiviewcontroller *p2 = [self.storyboard                             instantiateviewcontrollerwithidentifier:@"contentviewcontroller2"];     uiviewcontroller *p3 = [self.storyboard                             instantiateviewcontrollerwithidentifier:@"contentviewcontroller3"];      myviewcontrollers = @[p1,p2,p3];      [self setviewcontrollers:@[p1]                    direction:uipageviewcontrollernavigationdirectionforward                     animated:no completion:nil];       nslog(@"loaded!");  }  -(uiviewcontroller *)viewcontrolleratindex:(nsuinteger)index {     return myviewcontrollers[index]; }  -(uiviewcontroller *)pageviewcontroller:(uipageviewcontroller *)pageviewcontroller      viewcontrollerbeforeviewcontroller:(uiviewcontroller *)viewcontroller {     nsuinteger currentindex = [myviewcontrollers indexofobject:viewcontroller];      --currentindex;     currentindex = currentindex % (myviewcontrollers.count);     return [myviewcontrollers objectatindex:currentindex]; }  -(uiviewcontroller *)pageviewcontroller:(uipageviewcontroller *)pageviewcontroller       viewcontrollerafterviewcontroller:(uiviewcontroller *)viewcontroller {     nsuinteger currentindex = [myviewcontrollers indexofobject:viewcontroller];      ++currentindex;     currentindex = currentindex % (myviewcontrollers.count);     return [myviewcontrollers objectatindex:currentindex]; }   -(nsinteger)presentationcountforpageviewcontroller: (uipageviewcontroller *)pageviewcontroller {     return myviewcontrollers.count; }  -(nsinteger)presentationindexforpageviewcontroller: (uipageviewcontroller *)pageviewcontroller {     return 0; }  @end

you can use flag know initial view (first view).then use scroll enable , disable method prevent swipe.

-(void)setscrollenabled:(bool)enabled forpageviewcontroller:(uipageviewcontroller*)pageviewcontroller{ for(uiview* view in pageviewcontroller.view.subviews){     if([view iskindofclass:[uiscrollview class]]){         uiscrollview* scrollview=(uiscrollview*)view;         [scrollview setscrollenabled:enabled];         return;     } }

hope work.


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