Questions. Exams: no. Get by without own Mac? Why ios? ios vs Android restrictions. Selling in App store how hard to publish? Future of Objective-C?

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1 Questions Exams: no Get by without own Mac? Why ios? ios vs Android restrictions Selling in App store how hard to publish? Future of Objective-C? Grading: Lab/homework: 40%, project: 40%, individual report: 20%

2 Grading? How should it work in this course? Copyright by Mark J. Sebern

3 Grading (1) Letter Numeric (academic catalog) % of passing grades * A /31 = 25.8% AB /31 = 12.9% B /31 = 12.9% BC /31 = 12.9% C /31 = 12.9% CD /31 = 9.7% D /31 = 12.9% * Assumes uniform, linear distribution Copyright by Mark J. Sebern

4 Grading (2) Letter A AB B BC C CD D F Definition (VP of Academics, sent each quarter) Student has performed outstandingly in all regards and is clearly exceptional. Student has performed with excellence. Student has shown very high command of course content. Student has done a commendable job dealing with course content. Student has an adequate grasp of course content. Student has met fair expectations. Student has attained minimal expectations in the course. Student has not attained minimal expectations in the course. So, what grade is appropriate for "no errors" work? Copyright by Mark J. Sebern

5 Grading (3) What's a professor to do? Is this the choice? Conflicting messages from MSOE Which is closer to employee evaluation? Make students happier now Make graduates happier later Duty: preparation for lifelong career Copyright by Mark J. Sebern

6 How to Get an "A" Be "outstanding" and "exceptional"? What does that mean? Go a little beyond the requirements Demonstrate learning and thinking Talk to the prof Examples?? Copyright by Mark J. Sebern

7 Objective-C and Swift Introduction Dr. Mark Sebern SE-4910i

8 Objective-C Superset of C, with OO messaging that resembles Smalltalk (early 1980 s) Adopted by NeXT around 1988 Many OS X and ios libraries use NS prefix from NeXTStep user interface Supported by libraries (e.g., xxxkit)

9 Objective-C vs Java (1) Pointers instead of references Same concept: name/syntax changes Each class has two files Public interface in.h, private interface/ implementation in.m Automatic reference counting (ARC) Instead of garbage collection

10 Objective-C vs Java (2) Property mechanism for setters/getters Instance variables seldom declared explicitly (current Obj-C) Method syntax (more details later), no keywords for many language components Base class is NSObject, not Object (though Obj-C does have one)

11 Object Initialization Call instance method to initialize object state Auto *mytesla = [[Auto alloc] init]; Declare pointer variable Call class method to allocate heap memory Initialization methods can also take arguments, like Java constructors.

12 Sending a Message Actual arguments [mytesla closedoors: doorsselected andlock: YES]; Receiver object pointer Selector (method name) Method names must be unique; the full name here is closedoors:andlock:

13 Some Details (1) NSString - Objective-C string Like Java String class (immutable) Literal is a test" Not the same as a C string: "C string" id - untyped pointer type (like C void*)

14 Some Details (2) Array classes NSArray - immutable NSMutableArray - mutable (doh!) NSLog - write to console Format string, variable argument list Similar to Java String.Format or printf Prefaced with date/time stamp

15 Literals nil - null pointer literal like Java null Boolean (BOOL) YES - true NO - false

16 Object Initialization Swift var mytesla = Auto() Declare class var variable (or let constant) Invoke class initializer (indirectly) Initializers can also take arguments, like Java constructors.

17 Sending a Message Swift Actual arguments (often with external parameter names) mytesla.closedoors (doorsselected, andlock: true) Receiver object Selector (method name) Method signatures must be unique

18 Swift Some Details (1) String - Swift string Like Java String class (immutable) Literal format: "This is a test" AnyObject - untyped class reference type Type casting with as operator

19 Some Details (2) Swift Arrays let - immutable (constant) var - mutable (variable) can change length/contents println - write to console Insert variables with string interpolation println( Array length is \(ar.count) )

20 Swift Literals nil - null pointer literal like Java null Boolean (Bool) true - true false - false

21 Swift and Obj-C Most (all?) of UIKit and other frameworks written in Objective-C Xcode and libraries now support bridging from Obj-C types to Swift types, but they are not the same

22 Swift Numeric Types Int, Int8, Int16, Int32, Int64 UInt, UInt8, UInt16, UInt32, UInt64 Float, Double NSDecimalNumber (bridged from Obj-C) No implicit type conversions!!!

23 Value vs Reference struct vs class Types In C++, essentially no difference In Swift, struct is value and class is object Value types are always copied (immutable!) But compiler can optimize copy-on-write Constant ( let ) references can point to non-constant objects! Structs can also have properties and functions (methods), but no identity ( self pointer/reference) We ll start with classes, since they are more familiar.

24 Model-View-Controller Model Model Application state (data) View User interface Controller Controller Behavior Like the observer design pattern or OOD entity/boundary/controller objects View

25 MVC Method Calls Get/set data, invoke calculations, etc. Model Controller Get/set data, arrange UI elements, etc. Event callbacks View

26 Complex MVC Structures Model View Controller Controller In general, controllers communicate with only their own views and models, but may link to other controllers for access to other views and models. View

27 MVC Visibility Rules Controllers Know the identity of their associated model(s) and view(s) Models and views Generally do not know their controllers Do not communicate directly with each other These rules allow models and views to be reused by other controllers, in the same or other applications.

28 View Hierarchies Label view Image view Subview 1 Label view Text field view Main view OK Views have frame and bounds rectangles (CGRect)

29 View Controller Details Properties Outlets (IBOutlet designator) to UI elements VC state variables Methods (functions = func) viewwillxxx and viewdidxxx load, appear, disappear Actions (from UI elements)

30 Questions?