iOS 5 App Development 2

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. What is an example of a reason to write a getter?
NSObject
One; zero to many
Lazy instantiation.
Other MVC trios.


2. What is the base class for most objects in the iOS SDK?
for...in; don't change things inside the loop.
In the getter! This is called lazy instantiation.
Class XX = [Object class]
NSObject


3. How many superviews does a view have? How many subviews?
One; zero to many
constant NSString
NSDictionary; no - it's immutable.
[Object isMemberOfClass:[Classname class]]


4. What is the makeup of a CGSize?
The compiler adds code to count references.
Two floats - for width and height
line up the colons!
No. Use NSMutableArray - which is a subclass of NSArray.


5. What about the model and the view talking to one another?
id
Can handle any language because it uses Unicode.
[[UIView alloc] initWithFrame]
Never!


6. Is NSArray mutable?
self.view
A collection of collections in graph form. Can include NSArray - NSDictionary - NSNumber - NSString - NSData - and NSData.
id
No. Use NSMutableArray - which is a subclass of NSArray.


7. How about the model talking to the controller?

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8. All classes should have a __________________ to be called by subclasses.
On left side - is calling the setter - and on the right side - is calling the getter.
Call setNeedsDisplay:
No - it gets the data from the controller.
Designated initializer.


9. What about public/private in Objective-C?

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10. ________ is the .h file and __________ is the .m file.
zero/nil
[Object isMemberOfClass:[Classname class]]
Interface; Implementation
(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.


11. What does 'weak' mean?

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12. What to do in Xcode for short documentation? For full documentation?
A CGPoint and and a CGSize
option-click; option-double-click
Strongly.
Properties; instance variables


13. All properties are initialized to _____
No...but it has 'a way' to notify the controller to come ask for fresh data.
Can handle any language because it uses Unicode.
zero/nil
1) Create a context 2) Create paths 3) Set colors - fonts - widths 4) Stroke or fill the above-created paths.


14. The single-view template in Xcode does not...
To zero; so pointers are nil.
[Object isKindOfClass:[Classname class]]
create a model
On left side - is calling the setter - and on the right side - is calling the getter.


15. Does a view 'own' the data it displays?
NSData
self.view
[Class respondsToSelector:@selector(aMethod)]
No - it gets the data from the controller.


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

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17. How to instantiate an object?
Dash - Plus sign.
option-click; option-double-click
Two CGFloats for x and y
1.) Ask another object to do it - e.g. with mutableCopy. 2.) Call a class method - 3.) [[Classname alloc] init];


18. Show a private interface section.
self
@interface JGEmailLoginEmailViewController(){ NSMutableData _receivedData; }@property (weak -nonatomic) JGAppDelegate appDelegate;@property (weak - nonatomic) IBOutlet UITextField *txtfldEmailAddress;@end
Two CGFloats for x and y
@synthesize; write our own getter and/or setter.


19. What if I want to put a scalar into an NSArray or NSSet?
Wrap it in NSValue. And remember that NSValue immutable.
UIViewController.
Right-click on view - or even a subview like a button.
To zero; so pointers are nil.


20. Where do I initialize properties?
In the getter! This is called lazy instantiation.
A rectangular area
NSDictionary; no - it's immutable.
id; an object pointer


21. What do I use for a bag of bits?
NSArray; no - it's immutable.
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.
NSData
NSSet; no - it's immutable


22. Instance methods start with a ______ and class methods start with a ______.
One; zero to many
An outlet.
Dash - Plus sign.
NSNumber. For example numberWithDouble: and doubleValue:


23. What about the view talking to the controller?

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24. How can I save user information between launches of my app?
No...but it has 'a way' to notify the controller to come ask for fresh data.
NSUserDefaults - which stores a property list.
Immutable. But there are many methods that take an NSString and returned a modified one. This is fast and preferable to using NSMutableString.
Creating objects - or finding information relative to the class. The name of the class is the first thing in the square brackets.


25. If I need to convert a number to an object - use __________
Dash - Plus sign.
self.view
Sort of - in ways that it doesn't need to know much about the controller. For example: delegation.
NSNumber. For example numberWithDouble: and doubleValue:


26. Can the controller talking to the view?
On left side - is calling the setter - and on the right side - is calling the getter.
A rectangular area
line up the colons!
Yes. As much as it wants.


27. Objects in an array: are the pointed to strongly or weakly?
Lazy instantiation.
NSSet; no - it's immutable
Strongly.
Argument validation.


28. Use ______ to send debugging messages to the console. Use _____ for any object - which should return an string. Can also use ______.
No...but it has 'a way' to notify the controller to come ask for fresh data.
NSLog; %@; %d and other formatters
Right-click on view - or even a subview like a button.
Getter and setter methods.


29. Talk about NSString
Class XX = [Object class]
Can handle any language because it uses Unicode.
Points - to achieve device-independence
No - it gets the data from the controller.


30. In a nutshell: how to do custom drawing?
Yes. As much as it wants.
Override drawRect:
Import / handle multiple inclusion.
At runtime.


31. You can send a message to a...
Immutable. But there are many methods that take an NSString and returned a modified one. This is fast and preferable to using NSMutableString.
id
constant NSString
Other MVC trios.


32. How is ARC done?
NSSet; no - it's immutable
The compiler adds code to count references.
No. Use NSMutableArray - which is a subclass of NSArray.
At runtime.


33. The view is...

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34. What is the iOS term for a library?
Creating objects - or finding information relative to the class. The name of the class is the first thing in the square brackets.
A framework.
Yes. The controller knows everything about the model.
NSLog; %@; %d and other formatters


35. Is it always bad to send messages to id?

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36. How are local variables initialized in iOS 5?
To zero; so pointers are nil.
Can handle any language because it uses Unicode.
@synthesize; write our own getter and/or setter.
Dash - Plus sign.


37. Talk about BOOL variables.
NO is zero; YES is anything else.
MVC - for model-view-controller
Cocoa Touch - Media - Core Services - Core OS
Center of the frame - which is in the superview's coordinate system


38. Why are properties good?
Wrap it in NSValue. And remember that NSValue immutable.
(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.
Call setNeedsDisplay:
'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.'


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

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40. List the iOS hierarchy from top to bottom.
1.) Ask another object to do it - e.g. with mutableCopy. 2.) Call a class method - 3.) [[Classname alloc] init];
NSSet; no - it's immutable
Cocoa Touch - Media - Core Services - Core OS
NSDictionary; no - it's immutable.


41. How to tell if an object is of a particular class? (Write a line of code)
[Object isMemberOfClass:[Classname class]]
My rectangle in my superview's coordinate space
UIViewController.
A rectangular area


42. A property is just the combination of _______.
Can handle any language because it uses Unicode.
Center of the frame - which is in the superview's coordinate system
Action
Getter and setter methods.


43. Instead of 'include' statements - in Objective-C we use _______ which does ________
NSObject
Properties; instance variables
Import / handle multiple inclusion.
Lazy instantiation.


44. What about controller talking to the model?
Yes. The controller knows everything about the model.
Outlet; Action
@synthesize; write our own getter and/or setter.
Never!


45. There is no difference between _____ and _______ at runtime.
At runtime.
Center of the frame - which is in the superview's coordinate system
Designated initializer.
id; an object pointer


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

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47. Are local pointers to objects strong or weak? So what happens at the end of the routine?
No. It's fine.
Lazy instantiation.
[Class respondsToSelector:@selector(aMethod)]
Strong. Object memory is freed at the end of the routine.


48. What is at the top of the view hierarchy?
Class XX = [Object class]
UIWindow
MVC - for model-view-controller
The runtime system asks the object what its class is.


49. What is the center property of a UIView?

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50. What is used in lieu of pixels? And why?
Yes. As much as it wants.
@interface JGEmailLoginEmailViewController(){ NSMutableData _receivedData; }@property (weak -nonatomic) JGAppDelegate appDelegate;@property (weak - nonatomic) IBOutlet UITextField *txtfldEmailAddress;@end
Never!
Points - to achieve device-independence