CATiledLayer，iOS7瓷磚未更新

從iOS6升級到iOS7時，我認爲我發現了一個CATiledLayer的錯誤，我希望在提交給Apple之前由社區驗證它。CATiledLayer，iOS7瓷磚未更新

問題是，如果您的UIScrollView中包含許多CATiledLayer，則最終會停止更新。

我有一個樣本項目展示這裏的問題：

https://github.com/sbudhram/CATiledLayerBug

請下載並運行iOS6的VS iOS7的iPad上運行。

該項目在UIScrollView中生成900個CATiledLayer，分辨率爲3級。隨着用戶放大，圖塊更新爲更精細的分辨率。該代碼適用於iOS6，但最終在iOS7上停止更新。

我GOOGLE了四周，看看是否有人的有這種類似的問題，並發現這一點：

http://www.cocoanetics.com/2013/09/welcome-to-ios-7-issues/

這是不同的，雖然，因爲我相信這可以在沒有記憶發生警告。

這裏是UIViewController中相關的代碼：

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 
    // Do any additional setup after loading the view, typically from a nib. 

    self.scrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds]; 
    _scrollView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight; 
    _scrollView.backgroundColor = [UIColor yellowColor]; 
    _scrollView.contentSize = CGSizeMake(self.view.frame.size.width, self.view.frame.size.height); 
    _scrollView.minimumZoomScale = 1; 
    _scrollView.maximumZoomScale = 4.1; 
    _scrollView.zoomScale = 2; 
    _scrollView.showsHorizontalScrollIndicator = YES; 
    _scrollView.showsVerticalScrollIndicator = YES; 
    _scrollView.delegate = self; 
    [self.view addSubview:_scrollView]; 

    self.contentView = [[UIView alloc] initWithFrame:_scrollView.bounds]; 
    _contentView.backgroundColor = [UIColor lightGrayColor]; 
    [_scrollView addSubview:_contentView]; 

    CGFloat tileSize = 20.0f; 
    CGFloat tileSpacing = 4.0f; 

    for (int i = 0; i < 30; i++) { 
     for (int j = 0; j < 30; j++) { 

      CATiledLayer *tLayer = [CATiledLayer layer]; 
      tLayer.bounds = CGRectMake(0, 0, tileSize, tileSize); 
      tLayer.position = CGPointMake(tileSize/2 + i*(tileSpacing+tileSize), tileSize/2 + j*(tileSpacing+tileSize)); 
      tLayer.delegate = self; 
      tLayer.contentsGravity = kCAGravityResize; 
      tLayer.contentsScale = [[UIScreen mainScreen] scale]; 
      tLayer.masksToBounds = NO; 
      tLayer.opacity = 1.0f; 
      tLayer.backgroundColor = [UIColor colorWithRed:.2 green:.2 blue:.8 alpha:.5].CGColor; 
      tLayer.levelsOfDetail = 3; 
      tLayer.levelsOfDetailBias = 3; 
      tLayer.tileSize = CGSizeMake(1024., 1024.); 
      [_contentView.layer addSublayer:tLayer]; 

     } 
    } 
} 

- (void)scrollViewDidZoom:(UIScrollView *)scrollView { 
    NSLog(@"Zoom: %f", scrollView.zoomScale); 
} 

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView { 
    return _contentView; 
} 

- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx { 
    UIImage *drawImage = nil; 
    if (_scrollView.zoomScale < 2) { 
     drawImage = [UIImage imageNamed:@"low.png"]; 
     NSLog(@"Drawing - Low"); 
    } 
    else if (_scrollView.zoomScale < 4) { 
     drawImage = [UIImage imageNamed:@"med.png"]; 
     NSLog(@"Drawing - Med"); 
    } 
    else { 
     drawImage = [UIImage imageNamed:@"high.png"]; 
     NSLog(@"Drawing - Hi"); 
    } 

    CGContextScaleCTM(ctx, 1, -1); 
    CGContextTranslateCTM(ctx, 0, -layer.bounds.size.height); 
    CGContextDrawImage(ctx, layer.bounds, [drawImage CGImage]); 

}

下面是對iOS7會發生什麼的快照（一切都充滿在iOS6的）：

iOS7 Bug