UIPageViewController switch between static view controllers and keep(reuse) contents

Question

I have three view controllers: Settings,Chatbox and QuickMsg.

I want to use UIPageViewController to switch between these three view controllers. For each view controller, I don't want to re-initiate the view controller between swiping pages since it contains user inputed data and I want to persist the data. I defined three view controllers as static variables.

The screen goes black when I swipe between pages. Where have I done wrong?

Thanks a lot in advance!

ChatboxController, SettingController and QuickMsgController are three UIViewController controllers. PagingViewController.h

#import <UIKit/UIKit.h>
#import "ChatboxController.h"
#import "SettingController.h"
#import "PagingViewController.h"
#import "QuickMsgController.h"
@class ChatboxController;
@class SettingController;
@class QuickMsgController;
@interface PagingViewController : UIViewController<UIPageViewControllerDataSource>

@property (strong, nonatomic) UIPageViewController *pageController;

@property (assign, nonatomic) NSInteger index;
+(ChatboxController*) getChatboxController;
+(SettingController*) getSettingsController;
@end

PagingViewController.m

#import "PagingViewController.h"

@interface PagingViewController ()

@end

@implementation PagingViewController

static ChatboxController* chatboxViewController;
static SettingController* settingViewController;
static QuickMsgController* quickMessageViewController;
int defaultIndex=1;
NSArray *viewControllers;
+(ChatboxController*) getChatboxController
{
    return chatboxViewController;
}
+(SettingController*) getSettingsController
{
    return settingViewController;
}
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController {


    self.index--;
    if(self.index<0)
    {
        self.index=0;
    }
    return [self viewControllerAtIndex:self.index];

}
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController {

    self.index++;

    return [self viewControllerAtIndex:self.index];

}
- (UIViewController *)viewControllerAtIndex:(NSUInteger)index {
    NSLog(@"index:%d",index);
    if(index==1)
    {
        return chatboxViewController;
    }
    else if (index==0){
        return settingViewController;
    }else if(index==2)
    {
         NSLog(@"Quick Message");
        return quickMessageViewController;
    }else{
        NSLog(@"error here");
        return nil;
    }

}
- (NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController {
    // The number of items reflected in the page indicator.
    return 3;
}

- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController {
    // The selected item reflected in the page indicator.
    return defaultIndex;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    chatboxViewController= [self.storyboard instantiateViewControllerWithIdentifier:@"chatbox"];
    settingViewController= [self.storyboard instantiateViewControllerWithIdentifier:@"settings"];
    quickMessageViewController=[self.storyboard instantiateViewControllerWithIdentifier:@"quickmessages"];
    self.index=defaultIndex;

  //  [self performSelector:@selector(loadingNextView) withObject:nil afterDelay:2.0f];
    self.pageController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStyleScroll navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options:nil];

    self.pageController.dataSource = self;
    [[self.pageController view] setFrame:[[self view] bounds]];
    NSArray *viewControllers = [NSArray arrayWithObject:chatboxViewController];
    [self.pageController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];

    [self addChildViewController:self.pageController];
    [[self view] addSubview:[self.pageController view]];
    [self.pageController didMoveToParentViewController:self];

}


- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

Danilo Danilo · Accepted Answer · 2014-01-04T13:00:56

Put your content view controllers in an NSArray:

@property (nonatomic, strong) NSArray *contentViewControllers;

Use:


- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController
      viewControllerBeforeViewController:(UIViewController *)viewController {

    NSUInteger index = [self.contentViewControllers indexOfObject:viewController];

    if (index == 0) {
        return nil;
    }

    return self.contentViewControllers[index - 1];
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController
       viewControllerAfterViewController:(UIViewController *)viewController {

    NSUInteger index = [self.contentViewControllers indexOfObject:viewController];

    if (index >= self.contentViewControllers.count - 1) {
        return nil;
    }

    return self.contentViewControllers[index + 1];
}

- (NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController {
    return self.contentViewControllers.count;
}

- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController {
    return 0;
}

UIPageViewController switch between static view controllers and keep(reuse) contents

1 Answers