For the quote and your respond: I am not trying to implement the examples on an iPhone. What I meant was that my target for programming was the iPhone. Is the difference big enough when I am still in the learning phase? Again, thanks for the links, will look them through. There are concepts in common such as responders, target-action, and delegates , but the iOS world isn't starved for its own books anymore.
So, if you only want to program the iPhone, I suggest you find a Cocoa-Touch-specific book. Alternatively, just use the Apple docs—that's what I did when learning to program the Mac.
Took me a few days Thomas Clayson Thomas Clayson I have an iPhone app in mind that should not be too complex. That's my goal for now. The problem is: I have no idea where to start but the GUI. The 'just jump into it. Do some few examples, download some samples and figure them out' doesn't really work for me.
I hope you follow along what I mean : — Filuren. It's fairly short, but descriptive not as tedious as other tutorials Today, I bought another book that seems good for simple iPhone apps.
Uwe Keim Intentss Intentss 8, 4 4 gold badges 49 49 silver badges 59 59 bronze badges. Fahad Sadah Fahad Sadah 2, 3 3 gold badges 18 18 silver badges 27 27 bronze badges. I only know the basics in C a procedural language. Like if, else-if, do, while, for loops. Haven't touched pointers in C tho. That's just me, though. Can you offer me any good place to start learning Ruby or Python? Sounds likes that what I need to get started. I say don't lose hope! That books looks awesome! I like Aaron Hillegass, thinks he got a great way of teaching, and his use of word is fine for a Dane : For the documentation, is it possible you can link all of Apple's reference?
Tried their developer site, but I am not sure if it was the right documentation I found. Is this the right one, Mac Reference? The Overflow Blog. Does ES6 make JavaScript frameworks obsolete? Such methods are class methods, they return a pointer to an object of their own class and their name usually starts with the name of the class itself. For example, the following method:.
It returns the ready string that is initialized by the corresponding string with a final zero without calls of alloc and init :. As soon as the pointer to an object goes beyond the scope, memory that is allocated for it is lost if that is the last pointer to that object and leaks.
The paradigm of calculation of references to resources is supported in Objective-C to avoid such unwanted effects. Thus, each object has an integer counter that displays the number of pointers that refer to it. When this counter reaches zero, memory allocated for this object returns to the system.
This counter is equal to 1 after the call of the method of the alloc class. We need to send a retain message to an object to increase its value and release message to decrease the value. NSObject implements all these methods. Any our class inherits it. Here is an example of work with the counter:. Implementation of init is very important. It is the class constructor. Constructors differ in that they return id and their names always start with the word init , and the constructor by default is init itself.
The scheme of any constructor is like the one below:. Here is a typical specialized not default constructor for a class with two members of a type of a certain class and with one integer invariant:.
Implementation of release and retain for NSObject is ideologically as the shown below and we do not need to redefine it in derivative classes due to absence of access to the invariant of references counter:. It means that dealloc message is sent to the object itself. In the implementation of its method it can decrease counters of its invariants if necessary and pass the similar message to an object of a basic class so that it makes the same.
It is obvious that implementation of a dealloc method for NSObject will release memory allocated for the object. Usually, dealloc for a certain class looks as follows:.
A correct work with the calculation of references is very important when returning the object address from the method or when initializing invariant using a formal parameter. Usually, the so-called access methods are used for such things. They return and set invariants of objects. It is good practice to name the method that returns the invariant value in the same way as the invariant and to start the name of the method that sets its value with the set word:.
But if the invariant is an object of a certain class, a simple assignment is not enough because we need to take into account reference counters. The following three methods are applied to solve this problem:. Method of access for reading the value of invariant is always very simple:. The format string corresponds to C language standard. How does the method that parses the format understand, which symbols to place instead of id?
It will just place what the description method of the current object will return. This method is initially declared for the NSObject class. NSString redefines it to the output of its string contents. Having redefined it, any object can represent its string contents. For example, the class of a complex number with two invariants of the double type can perform this as follows:. There will be a memory leak after performing the sayHelloToName:withSurname: method.
The calling code will not guess that the release message must be sent to the returned object after processing. Even if it performs that, it can happen that the pointer to object invariant is returned and it means that its deletion can have serious consequences. It would be great to have a mechanism of self-release of objects in future so that the user code did not need to release them. This problem can be solved with the help of an object of the NSAutoreleasePool class — autorelease pool of objects.
We can send the autorelease message to all objects created after the creation of an object of such class. Such object is placed to the current the last created autorelease pool. When a certain pool receives the release message, it sends the same message to all its objects. It also decreases their reference counter in fact, deleting it. Thus, an object placed into the autorelease pool continues living and occupies memory during the whole pool life. It is convenient for small temporary objects but it can occupy a significant part of the memory with the course of time.
That is why it is recommended to frame cycles that can create a lot of temporary objects, which move to the autorelease pool, with the local embedded pools. Any thread in the program that uses Cocoa must create an object of the NSAutoreleasePool class in the beginning before creating other objects and delete it at the end after deleting all other objects.
The main function that is the main thread of any program in Objective-C must look like this when using the Cocoa framework:. Besides, the drain method of the autorelease pool is similar to release. The only difference is that except the release of itself and other objects contained in it, it prompts the garbage collector to go in.
But it is actual only for Mac OS By default, the constructor calls the specialized constructor with the defined initial parameters. The complexWithRe:andIm: method returns the initialized object of the Complex class that is located in the current autorelease pool.
The description method performs the same and returns the object of the NSString class. Here is an example of a program where the Complex class is used:. There can be required required specificator that is considered as a default one and selective optional specificator protocol methods in the language version 2.
If any class implemented the required protocol methods, it is called a class that supports this protocol. Protocol and class that supports it are declared as follows:. We can send the print and switchedOn messages to an object of the MyPrinter class. After checking for respondsToSelector: , we can send the loadPaper: message as there must be definitions of the similar methods in its implementation. This is not to be mistaken with subclasses.
Subclass instead to override methods. A good example would be to clean the car. Shape instances cannot call me. Only implementation does. Class implements it however it wants. Without it, compiler will throw error. NSLog "You may have as many lines in a block as you would like. When the application is done using that object, memory must be deallocated to ensure application efficiency.
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