bug UIPageControl: montrant une balle d'abord, puis tout montrer

Question

J'ai un comportement étrange en utilisant un UIPageControl:

D'abord, il apparaît avec une seule balle, puis quand je déplace la vue de défilement toutes les balles apparaissent correctement. Y a-t-il quelque chose qui me manque avant de l'ajouter comme sous-vue?

Voici mon code imageScrollView.h:

@interface ImageScrollView : UIView <UIScrollViewDelegate> { 
    NSMutableDictionary *photos; 
    BOOL *pageControlIsChangingPage; 
    UIPageControl *pageControl; 
} 
@property (nonatomic, copy) NSMutableDictionary *photos; 
@property (nonatomic, copy) UIPageControl *pageControl; 
@end 

Voici le code pour imageScrollView.m:

#import "ImageScrollView.h" 


@implementation ImageScrollView 
@synthesize photos, pageControl; 

- (id)initWithFrame:(CGRect)frame { 
    if ((self = [super initWithFrame:frame])) { 
    // Initialization code 
    } 
    return self; 
} 

- (void) drawRect:(CGRect)rect 
{ 
    [self removeAllSubviews]; 

    UIScrollView *scroller = [[UIScrollView alloc]  initWithFrame:CGRectMake(0,0,self.frame.size.width,self.frame.size.height)]; 
    [scroller setDelegate:self]; 

    [scroller setBackgroundColor:[UIColor grayColor]]; 

    [scroller setShowsHorizontalScrollIndicator:NO]; 
    [scroller setPagingEnabled:YES]; 

    NSUInteger nimages = 0; 
    CGFloat cx= 0; 

    for (NSDictionary *myDictionaryObject in photos) 
    { 
    if (![myDictionaryObject isKindOfClass:[NSNull class]]) { 
    NSString *photo =[NSString stringWithFormat:@"http://www.techbase.com.mx/blog/%@",[myDictionaryObject objectForKey:@"filepath"]]; 
    NSDictionary *data = [myDictionaryObject objectForKey:@"data"]; 

    UIView *imageContainer = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height - 30)]; 

    TTImageView *imageView = [[TTImageView alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height - 30)]; 
    imageView.urlPath=photo; 
    [imageContainer addSubview:imageView]; 

    UILabel *caption = [[UILabel alloc] initWithFrame:CGRectMake(0,imageView.frame.size.height,imageView.frame.size.width,10)]; 

    [caption setText:[NSString stringWithFormat:@"%@",[data objectForKey:@"description"]]]; 
    [caption setBackgroundColor:[UIColor grayColor]]; 
    [caption setTextColor:[UIColor whiteColor]]; 
    [caption setLineBreakMode:UILineBreakModeWordWrap]; 
    [caption setNumberOfLines:0]; 
    [caption sizeToFit]; 
    [caption setFont:[UIFont fontWithName:@"Georgia" size:10.0]]; 
    [imageContainer addSubview:caption]; 

    CGRect rect = imageContainer.frame; 
    rect.size.height = imageContainer.size.height; 
    rect.size.width = imageContainer.size.width; 
    rect.origin.x = ((scroller.frame.size.width - scroller.size.width)/2) + cx; 
    rect.origin.y = ((scroller.frame.size.height - scroller.size.height)/2); 
    imageContainer.frame=rect; 
    [scroller addSubview:imageContainer]; 
    [imageView release]; 
    [imageContainer release]; 
    [caption release]; 

    nimages++; 
    cx +=scroller.frame.size.width; 

    } 

    } 

    [scroller setContentSize:CGSizeMake(nimages * self.frame.size.width, self.frame.size.height)]; 
    [self addSubview:scroller]; 
    pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(self.frame.size.width/2, self.frame.size.height -20, (self.frame.size.width/nimages)/2, 20)]; 
    pageControl.numberOfPages=nimages; 
    [self addSubview:pageControl]; 

    [scroller release]; 

    } 

    -(void)dealloc { 
    [pageControl release]; 
    [super dealloc]; 
    } 


    -(void)scrollViewDidScroll:(UIScrollView *)_scrollView{ 
    if(pageControlIsChangingPage){ 
    return; 
    } 
    CGFloat pageWidth = _scrollView.frame.size.width; 
    int page = floor((_scrollView.contentOffset.x - pageWidth /2)/pageWidth) + 1; 
    pageControl.currentPage = page; 
    } 

    -(void)scrollViewDidEndDecelerating:(UIScrollView *)_scrollView{ 
pageControlIsChangingPage = NO; 
} 

@end 

Answer 1

Depuis que vous dessinez la UIPageControl dans la méthode drawRect, vous devez appelez la méthode setNeedsLayout de ce contrôle après l'avoir initialisé. Sinon, il ne se rendra pas correctement jusqu'à ce qu'un événement qui force ce redessin soit appelé.

pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(self.frame.size.width/2, self.frame.size.height -20, (self.frame.size.width/nimages)/2, 20)]; 
pageControl.numberOfPages=nimages; 
[pageControl setNeedsLayout]; 
[self addSubview:pageControl];