iOS UIPageViewControlleR语言 由于未捕获的异常'Invalid parameter not satisfying: [views count] == 3'而终止应用程序

Question

我有一个页面视图控制器，我收到错误Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid parameter not satisfying: [views count] == 3'

这是我的数据源：

//
//  MSABDrawingPageModelController.m
//  My Special Alphabet Book
//
//  Created by Ari Porad on 9/3/13.
//  Copyright (c) 2013 Cari Books. All rights reserved.
//
#import "MSABDrawingPageModelController.h"
#import "MSABDrawingViewController.h"
#import "MSABDrawingView.h"
@implementation MSABDrawingPageModelController
-(id)initWithLetter:(MSABLetter *)letter{
    if (self = [super init]) {
        self.letter = letter;
    }
    return self;
}
-(id)init{
    return [self initWithLetter:nil];
}
-(NSURL *)docsDirUrl{
    return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] objectAtIndex:0];
}
-(UIViewController *)viewControllerAtIndex:(int)index{
    MSABDrawingViewController *VC = [[UIStoryboard storyboardWithName:@"Main" bundle:[NSBundle mainBundle]] instantiateViewControllerWithIdentifier:@"MSAB_DRAWING_VIEW_CONTROLLER"];
    ((MSABDrawingView *) VC.view).points = [NSMutableArray arrayWithArray:@[[NSMutableArray array]]];
    VC.index = index;
    VC.letter = self.letter;
    return VC;
}
#pragma mark -
#pragma mark Page View Controller Data Source Methods
-(UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController{
    UIViewController *vc = [self viewControllerAtIndex:((MSABDrawingViewController *)viewController).index + 1];
    if(vc == nil){
        vc = [[MSABDrawingViewController alloc] init];
    }
    NSLog(@"AVC: %@", vc);
    return vc;
}
-(UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController{
    UIViewController *vc = [self viewControllerAtIndex:((MSABDrawingViewController *)viewController).index - 1];
    if(vc == nil){
        vc = [[MSABDrawingViewController alloc] init];
    }
    NSLog(@"PVC: %@", vc);
    return vc;
}
@end

如果还有什么需要知道的，请告诉我。

Answer 1

我遇到了同样的问题。

事实证明，您必须设置 uipageviewController 的初始视图控制器，无论您是通过 IB 还是以编程方式设置它。

源：https://developer.apple.com/library/ios/documentation/WindowsViews/Conceptual/ViewControllerCatalog/Chapters/PageViewControllers.html#//apple_ref/doc/uid/TP40011313-CH4-SW10

调用 setViewControllers:direction:animated:completion: 方法并设置初始视图控制器数组。