Recently I had given couple of presentations on Multithreading using NSOperations and GCD. Here is the first draft of transcript. CPU (Central Processing Unit) WHY I’m starting from here, because...

NSRunLoop (A wrapper of CFRunLoop) Nothing but a loop or a event processing loop, where your thread enters, where it runs event handlers for incoming events. They handle (manage/monitor) input...

When you have a view controller under navigation controller presented as model view then you have to add a method (given below) into navigation controller through categories. - (BOOL)disablesAutom...

NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys: [UIFont fontWithName:@”Arial” size:22],UITextAttributeFont, [UIColor whiteColor], UITextAttributeTextColor, [UIColor grayColor], UITe...

Assertion is a defence against programming errors. It tests a condition, and if the condition fails, it raises an exception. This is processed by the current exception handler, which by default cal...

Protocols in Objective C is a Class from which structure is inherited, not implementation. A protocol is means to define a list of required and/or optional methods that a class implements. If a cl...

Object Ownership: 1. Object creation: alloc, init, new, copy, 2. Take Ownership: retain 3. must relinquish ownership of objects we own. 4. must not relinquish ownership of objects we do not own. R...

Delegates Delegation design pattern is a way of modifying complex objects without sub classing them. Instead of sub classing, we use the complex object as it is and put any custom code for modifyi...

Benefits A way of sectioning code. Categories are used for better code organisation. Distribute the implementation of your own classes into separate source files—for example, you could group th...

Blocks are an extension to the C language and thus fully supported in Objective-C. There are two ways to use block: The most common way to use a block is to pass it to a method that in turn ca...