Instructions:

• Answer 50 questions in 15 minutes.
• If you are not ready to take this test, you can study here.
• Match each statement with the correct term.
• Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Objects in an array: are the pointed to strongly or weakly?
Strong. Object memory is freed at the end of the routine.
(1) We can validate (e.g. bounds-check) any sets done by a subclass. (2) We can lazily instantiate - so things only get created if and when they are needed.
Yes. The controller knows everything about the model.
Strongly.


2. In synthesize: @synthesize foo = _foo; The __foo_ is the ____________ or also known as the ___________________.

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3. Where do I initialize properties?
On left side - is calling the setter - and on the right side - is calling the getter.
In the getter! This is called lazy instantiation.
Argument validation.
Call setNeedsDisplay:


4. What is the iOS term for a library?
Points - to achieve device-independence
(1) We can validate (e.g. bounds-check) any sets done by a subclass. (2) We can lazily instantiate - so things only get created if and when they are needed.
A framework.
create a model


5. What is the frame property of a UIView?

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6. The decision on what method to call is made when?
An outlet.
for...in; don't change things inside the loop.
At runtime.
Yes. As much as it wants.


7. In a nutshell: how to do custom drawing?
Two CGFloats for x and y
'Keep this in the heap until I don't point to anymore.' I won't point to it anymore if I set my pointer to nil - or if I am removed from the heap because no one points strongly to me.
Override drawRect:
One; zero to many


8. ______ is a pointer to any object.
Class XX = [Object class]
Center of the frame - which is in the superview's coordinate system
A rectangular area
id


9. What is an example of a reason to write a getter?
Center of the frame - which is in the superview's coordinate system
Lazy instantiation.
addSubview; removeFromSubview
line up the colons!


10. How to do enumeration with NSArray - NSDictionary - etc?

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11. The setters for outlets are called by _______ at this point ______________.
Wrap it in NSValue. And remember that NSValue immutable.
Right-click on view - or even a subview like a button.
iOS; when the view is loaded.
UIWindow


12. What about controller talking to the model?
Yes. The controller knows everything about the model.
addSubview; removeFromSubview
Never!
NSSet; no - it's immutable


13. Talk about NSString
Lazy instantiation.
Can handle any language because it uses Unicode.
A CGPoint and and a CGSize
NO is zero; YES is anything else.


14. If I need to convert a number to an object - use __________
NSNumber. For example numberWithDouble: and doubleValue:
Class XX = [Object class]
The document; possibly a database.
internal origin and size. Use this inside a view


15. How can I find out the class of any object? Give a line of code.
'Keep this in the heap as long as someone else points to it strongly. If it gets thrown out of the heap - set my pointer to it to nil.'
Immutable. But there are many methods that take an NSString and returned a modified one. This is fast and preferable to using NSMutableString.
Class XX = [Object class]
Never!


16. ______ is a pointer
self
Don't use id for a pointer. Use the actual type pointed to. It allows the compiler (but not the runtime!) to help find bugs.
NSObject
option-click; option-double-click


17. What is the word for checking/verifying the type of an object?

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18. What is the name of a property in the controller that it uses to talk to views?
Outlet; Action
Getter and setter methods.
An outlet.
Instance method; class method.


19. How are local variables initialized in iOS 5?
To zero; so pointers are nil.
The document; possibly a database.
id
'Keep this in the heap until I don't point to anymore.' I won't point to it anymore if I set my pointer to nil - or if I am removed from the heap because no one points strongly to me.


20. How can I save user information between launches of my app?
@interface JGEmailLoginEmailViewController(){ NSMutableData _receivedData; }@property (weak -nonatomic) JGAppDelegate appDelegate;@property (weak - nonatomic) IBOutlet UITextField *txtfldEmailAddress;@end
An outlet.
NSUserDefaults - which stores a property list.
Yes. The controller knows everything about the model.


21. How about the model talking to the controller?

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22. What is the makeup of a CGPoint?
Two CGFloats for x and y
NSNumber. For example numberWithDouble: and doubleValue:
Two floats - for width and height
My rectangle in my superview's coordinate space


23. A _______ is how a view notifies the controller of something - for example - a button press.
Action
Lazy instantiation.
NSData
Getter and setter methods.


24. In the initializer methods of objects I create - add what line of code? Why?
id
In the getter! This is called lazy instantiation.
One; zero to many
self = [super init] {if init is the designated initializer of the superclass}. If the superclass init routine fails - I will know to return nil from my init routine.


25. How to tell if an object is of a particular class? (Write a line of code)
A CGPoint and and a CGSize
A rectangular area
[Object isMemberOfClass:[Classname class]]
@interface JGEmailLoginEmailViewController(){ NSMutableData _receivedData; }@property (weak -nonatomic) JGAppDelegate appDelegate;@property (weak - nonatomic) IBOutlet UITextField *txtfldEmailAddress;@end


26. What is the base class for most objects in the iOS SDK?
Never!
NSObject
The document; possibly a database.
self


27. What does the controller do?
Controls how the model is presented onscreen.
iOS; when the view is loaded.
NSLog; %@; %d and other formatters
Getter and setter methods.


28. What is used in lieu of pixels? And why?
Import / handle multiple inclusion.
Points - to achieve device-independence
@interface JGEmailLoginEmailViewController(){ NSMutableData _receivedData; }@property (weak -nonatomic) JGAppDelegate appDelegate;@property (weak - nonatomic) IBOutlet UITextField *txtfldEmailAddress;@end
A CGPoint and and a CGSize


29. What does 'strong' mean?

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30. Why are properties good?
No. Use NSMutableArray - which is a subclass of NSArray.
Class XX = [Object class]
Points - to achieve device-independence
(1) We can validate (e.g. bounds-check) any sets done by a subclass. (2) We can lazily instantiate - so things only get created if and when they are needed.


31. How to create a UIView in code?
[[UIView alloc] initWithFrame]
Controls how the model is presented onscreen.
@synthesize; write our own getter and/or setter.
The document; possibly a database.


32. Class methods are used for ___________ and the call starts with ____________.
Creating objects - or finding information relative to the class. The name of the class is the first thing in the square brackets.
NO is zero; YES is anything else.
Instance method; class method.
Right-click on view - or even a subview like a button.


33. What is the makeup of a CGRect?
The runtime system asks the object what its class is.
A CGPoint and and a CGSize
NO is zero; YES is anything else.
Properties; instance variables


34. How many superviews does a view have? How many subviews?
NSLog; %@; %d and other formatters
Sort of - in ways that it doesn't need to know much about the controller. For example: delegation.
Never!
One; zero to many


35. Are local pointers to objects strong or weak? So what happens at the end of the routine?
A rectangular area
No. Use NSMutableArray - which is a subclass of NSArray.
internal origin and size. Use this inside a view
Strong. Object memory is freed at the end of the routine.


36. A _______ goes from the Controller to the View. A ________ goes from the view to the controller.
option-click; option-double-click
Getter and setter methods.
Outlet; Action
Two CGFloats for x and y


37. When is it OK to call drawRect: directly?
Never!
Class XX = [Object class]
Properties; instance variables
Yes. As much as it wants.


38. Remember that it's cool to...
internal origin and size. Use this inside a view
line up the colons!
NSNumber. For example numberWithDouble: and doubleValue:
Strongly.


39. Instead of 'include' statements - in Objective-C we use _______ which does ________
Can handle any language because it uses Unicode.
[[UIView alloc] initWithFrame]
The runtime system asks the object what its class is.
Import / handle multiple inclusion.


40. When happens when you send a message to nil?
NSObject
Lazy instantiation.
Can handle any language because it uses Unicode.
Nothing happens - and nil is returned.


41. How to tell whether an object implements a particular method? (A line of code)
[Class respondsToSelector:@selector(aMethod)]
Never!
[Object isMemberOfClass:[Classname class]]
the controller's minions. Gets things to the screen.


42. What about the model and the view talking to one another?
for...in; don't change things inside the loop.
Call setNeedsDisplay:
Never!
[Object isKindOfClass:[Classname class]]


43. What is static typing? Why is it good?

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44. ________ implements the getter and setter. But we can always__________
@synthesize; write our own getter and/or setter.
Nothing happens - and nil is returned.
NSSet; no - it's immutable
Other MVC trios.


45. Some controllers have ____________ as their views.
Other MVC trios.
[Object isMemberOfClass:[Classname class]]
option-click; option-double-click
Nothing happens - and nil is returned.


46. How to see all actions - outlets - incoming/outgoing segues on a view?
Properties; instance variables
Right-click on view - or even a subview like a button.
Instance method; class method.
In the getter! This is called lazy instantiation.


47. What do I use for an ordered collection of objects? And is it mutable?

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48. What to do in Xcode for short documentation? For full documentation?
[Object isMemberOfClass:[Classname class]]
Instance method; class method.
Argument validation.
option-click; option-double-click


49. Talk about BOOL variables.
Points - to achieve device-independence
NO is zero; YES is anything else.
NSObject
the controller's minions. Gets things to the screen.


50. Calling a method on id works just fine because....?
internal origin and size. Use this inside a view
Strong. Object memory is freed at the end of the routine.
The runtime system asks the object what its class is.
UIWindow