iOS & Objective C programming Notes & Links

A collection of notes written by me while developing KegCop

Definitions

• Objective-C - a collection of syntactic extensions to the C programming language to add objects.
• Application Life Cycle - main() → UIApplicationMain() → UIApplication Object → event loop listening to user input
• Protocol - is a set methods an object agrees to implement.

Fun Facts

• Objective-C is a dynamically linked language.
• There are over 3000 methods and more than 200 classes available in iOS.
• XIB is pronounced zib
• NSObject - the root class of the entire class hierarchy
• .mm - denotes an Objective-C++ file.

Useful Links

• StackOverflow - multiple views contained within XIB
• objectivec2swift.com - convert objc to swift
• YouTube - Creating a Cydia repository
• StackOverflow - QnA - Delegation

Code Examples

Hello, World! - Objective-C

#include 
int main(int argc, char *argv[])
{
printf(“hello, world\n”);
return 0;
}

Hello, World! - C++

#include 
int main()
{
    std::cout << “Hello, world!\n”;
}

Hello, World! - Java

public class Hello {
    public static void main(String[] args) {
        System.out.println(“Hello, world!”);
    }
}

Comparing Objective-C message sending to other OO languages

• C++: someObject->doSomething();
• Java: someObject.doSomething();
• Objective-C: [someObject doSomething];

Methods and messages

To call a method in Objective-C

[myObject someMethod];

To pass arguments

[myObject someMethod:arg];

Managing the build version of iOS app

Useful commands with working the build version of an app

agvtool
agvtool what-version
agvtool bump -all

To change the marketing version

agvtool new marketing-version <0.4.2>

Xcode keyboard shortcuts

• To switch between the .h / .m files or counterparts of a class using Xcode
  ctrl+⌘+↑
• To toggle the navigator pane of Xcode
  ⌘+0
• To show the assistant editor ⌘+option+enter
• To hide the assistant editor ⌘+enter
• To highlight / show the current file open in editor via the navigator pane ⌘+shift+j
• To toggle the utilities pane ⌘+option+0
• To launch the open quickly input ⌘+shift+o