小编Eri*_*Gao的帖子

我有一个CAGradientLayer插入到应用程序底部弹出的这个小细节视图的底部.正如你所看到的,我将颜色从白色设置为清晰,但是出现了这种奇怪的灰色色调.有任何想法吗？

    // Set up detail view frame and gradient
    [self.detailView setFrame:CGRectMake(0, 568, 320, 55)];

    CAGradientLayer *layer = [CAGradientLayer layer];
    layer.frame = self.detailView.bounds;
    layer.colors = [NSArray arrayWithObjects:(id)[UIColor whiteColor].CGColor, (id)[UIColor clearColor].CGColor, nil];
    layer.startPoint = CGPointMake(1.0f, 0.7f);
    layer.endPoint = CGPointMake(1.0f, 0.0f);
    [self.detailView.layer insertSublayer:layer atIndex:0];

这是有问题的观点:

所以我有一个旧的敏感访问密钥,当前具有kSecAttrAccessible WhenUnlocked的可访问性,我想将其更新为kSecAttrAccessibleAfterFirstUnlock.

我正在使用Lockbox并调用此方法:

[Lockbox setString:accessKey forKey:self.accessKeyName accessibility:kSecAttrAccessibleAfterFirstUnlock];

反过来,这称之为:

-(BOOL)setObject:(NSString *)obj forKey:(NSString *)key accessibility:(CFTypeRef)accessibility
{
    OSStatus status;

    NSString *hierKey = [self _hierarchicalKey:key];

    // If the object is nil, delete the item
    if (!obj) {
        NSMutableDictionary *query = [self _query];
        [query setObject:hierKey forKey:(LOCKBOX_ID)kSecAttrService];
        status = SecItemDelete((LOCKBOX_DICTREF)query);
        return (status == errSecSuccess);
    }

    NSMutableDictionary *dict = [self _service];
    [dict setObject: hierKey forKey: (LOCKBOX_ID) kSecAttrService];
    [dict setObject: (LOCKBOX_ID)(accessibility) forKey: (LOCKBOX_ID) kSecAttrAccessible];
    [dict setObject: [obj dataUsingEncoding:NSUTF8StringEncoding] forKey: (LOCKBOX_ID) kSecValueData];

    status = SecItemAdd ((LOCKBOX_DICTREF) dict, NULL);
    if …

我对层掩蔽如何工作有一些困难.现在,我有一个带UILabels的UIView.我想象两层 - 一层是背面的UIView,另一层是顶部的标签.如果我屏蔽UIView图层,标签也会受到蒙版的影响.

UILabels是父UIView的孩子,所以我也能理解影响孩子的父面具.

但是,当我从图层来看它时,它似乎没有意义.为什么屏蔽最深层会影响到最顶层？