khorbushko

    ACTION = build
    AD_HOC_CODE_SIGNING_ALLOWED = NO
    ALTERNATE_GROUP = staff
    ALTERNATE_MODE = u+w,go-w,a+rX
    ALTERNATE_OWNER = grantdavis
    ALWAYS_SEARCH_USER_PATHS = NO
    ALWAYS_USE_SEPARATE_HEADERMAPS = YES
    APPLE_INTERNAL_DEVELOPER_DIR = /AppleInternal/Developer
    APPLE_INTERNAL_DIR = /AppleInternal
    APPLE_INTERNAL_DOCUMENTATION_DIR = /AppleInternal/Documentation

khorbushko

##Creating a timer with Grand Central Dispatch

At the following is the implementation file of a sample class that shows, how to make a timer with the help of Grand Central Dispatch. The timer fires on a global queue, just change the queue to the main queue or any custom queue and the timer fires on this queue and not on the global queue anymore.

#import <Foundation/Foundation.h>

@interface SampleClass : NSObject
- (void)startTimer;

khorbushko

mr	Marathi
bs	Bosnian
ee_TG	Ewe (Togo)
ms	Malay
kam_KE	Kamba (Kenya)
mt	Maltese
ha	Hausa
es_HN	Spanish (Honduras)
ml_IN	Malayalam (India)
ro_MD	Romanian (Moldova)

khorbushko

1. The Layer Tree

Core Animation's original name is Layer Kit

Core Animation is a compositing engine; its job is to compose different pieces of visual content on the screen, and to do so as fast as possible. The content in question is divided into individual layers stored in a hierarchy known as the layer tree. This tree forms the underpinning for all of UIKit, and for everything that you see on the screen in an iOS application.

In UIView, tasks such as rendering, layout and animation are all managed by a Core Animation class called CALayer. The only major feature of UIView that isn’t handled by CALayer is user interaction.

There are four hierarchies, each performing a different role:

• view hierarchy
• layer tree

khorbushko

NSString *NSStringFromOSStatus(OSStatus errCode)
{
    if (errCode == noErr)
        return @"noErr";
    char message[5] = {0};
    *(UInt32*) message = CFSwapInt32HostToBig(errCode);
    return [NSString stringWithCString:message encoding:NSASCIIStringEncoding];
}