Elance iOS Technical Test Answers 2015
·
True or False? When you create a new iOS project from a template, the template automatically makes a controller object for you.
FALSE
True
In Objective C, when an application launches and runs the 'main' function, the frame for 'main' is put at the _____ of the stack.
bottom
top
How can an application respond to they keyboard being dismissed by the user
UIKeyboardWillHideNotification
[UIResponder
shouldResignFirstResponder]
This cannot
be done
[UIResponder
didResignFirstResponder]
[UIResponder
resignFirstResponder]
If you have a CGPathRef and need to draw this path to a core animation layer, which object would you use.
CALayer
CGPathLayer
CAShapeLayer
CGPathRefLayer
CAPathLayer
Which one of the following is true?
You
can only create and draw to an image context on the main thread
You can
modify UIKit drawing on a background thread
None of
these are true
You
can modify Core Animation layers on a background thread
Which scenario will not result in NSOperation throwing an exceptions:
When
you try to add a completion block to an operation that is already executing or
finished.
When
the return value from a completion block is nil.
When you
try to retrieve the result of an NSInvocationOperation object that was canceled.
When the
operation is executing or finished (possibly because it was canceled) and its
start method is called again.
When the
operation is not ready to execute but its start method is called.
NSXMLParser is which kind of parser ?
DOM
Parser
SAX
Parser
Which 3D Framework was added in iOS since iOS 8?
CoreGraphics
CoreAnimation
Quartz
SpriteKit
SceneKit
What object is responsible for launch time initalization and transitions?
viewDidAppear
Main.m
AppDelegate
viewDidLoad
Which of the following best describes the differences between iOS 7 and iOS 6?
iOS
6 is not supported on iPhone 5s and iPhone 5c
iOS 7 user
interface has been completely redesigned.
iOS 7
supports Autolayout.
iOS
7 user interface has been completely redesigned and has 64-Bit Support.
In Objective C, what happens when you send a message to a variable that is nil?
You
will receive an error message
None of
these
Nothing
happens
You will
receive a confirmation
Automatic migration between Core Data model versions is sufficient for many cases. Which one of the following cases would require additional migration code?
A
mandatory attribute is made optional
A new
attribute has been added to an Entity
An optional
attribute is made required
A
relationship has changed from a 'to-one' to a 'to-many' relationship
What structure can be used to define a portion of a series?
CGPoint
NSSet
NSRange
NSString
In ARC enabled project: [someObject release];
Crash
on run time
Nothing
will do
Compile
error
Some time
crash some time run well
Which of the following code snippets would work for changing the position of a view?
(none
of these)
CGPoint
center = view.center; center.x = 0; center.y = 100; view.center = center;
view.frame.x
= 0; view.frame.y = 100;
view.frame.size.x
= 0; view.frame.size.y = 100;
+(void)doSomething{}
Both
true
Is a
instance method
both false
Is
a class method
Which of the following objects is considered "the managers in an application" by keeping the other objects in sync?
All
of these
View objects
Controller
objects
Model
objects
Which of the following holds data and knows nothing about the user interface?
Model
objects
View objects
Controller
objects
All of these
What is used to sort Core Data results?
[self
sort]
NSSort
NSSortDescriptor
NSCoreDataSort
In order to test your application in XCode, which testing frameworks are available?
OCMock,
OCUnit, XCTest
(all of
these)
Tes.ting
NUnit, JUnit
MinUnit,
IOSUnit
What is the difference between Cocoa and Cocoa Touch?
Cocoa
Touch is the application framework for developing applications in Mac OS X.
Cocoa is the application framework for iPhone,iPad and iPod Touch .
Cocoa Touch
is another name for a Cocoa framework
Cocoa
is the application framework for developing applications in Mac OS X. Cocoa
Touch is the application framework for iPhone,iPad and iPod Touch .
What function do you call to close the current view and go back to the root?
closeCurrentView
popToMainViewController
popToRootViewController
pushRootViewController
True or False: viewDidLoad comes after viewDidAppear?
False
True
What's the difference between a frame and bounds?
It's
the same
Bounds
origin is always (0, 0), a frame origin is relative to his container view
Frame is
for UIKit objects, bounds are for CoreGraphics.
What is a category?
A
way to add instance variables to a class which already exists
A namespace
A group of
classes
A
category is a way to add methods to a class which already exists
If you use threading, on which thread should UI Transitions be called?
The
main thread
The
background thread
Concurrent
threads
Any thread
What data type do you initialize if you want a list of items that can change?
NSDictionary
NSMutableDictionary
NSMutableArray
NSArray
What is the function in Objective C that determines what is in the cells of a tableView?
cellForTableView
cellForRowAtIndexPath
tableViewCellContents
tableView.cell.content
What structure can hold an x and y coordinate that defines a location?
CGSize
CGRect
NSFrame
CGPoint
Is it possible to make a full application without using Interface Builder?
Yes,
on any platform
No, you
always have to use Interface Builder to meet Apple's app standards
Yes, but
only for iPad
Which of the following objects is visible to the user?
Model
objects
Controller
objects
None of
these
View
objects
In manual memory management, what do you do when you don't need a reference on a object ?
[obj
free]
free(obj)
[obj
dealloc]
[obj
release];
If an asset is for iPad only, how do you specify it in the file name?
!iPad
~iPad
~iPhone
!iPhone
What data object can store a timestamp the best?
NSArray
NSString
NSDate
NSNumber
An indexPath has a Section and a ____
Grid
Column
Coordinate
Row
or item
What data type do you initialize if you want a string that can change?
NSMutableString
NSString
NSCore
NSChangeableString
What is @2x used for?
Retina
Assets
NSStrings
Normal
Assets
All Images
The archive that holds the saved create and configure view objects is known as:
XID
XBI
XML
XIB
ARC Stands for:
Automatic
Retained Collections
Autoreleased
Reference Counters
Automatic
Reference Counting
Allocated
Reference Cycles
Which of the following symbols do you prefix a character string with when you want a hard coded string?
#
&
@
*
How do you reference your app bundle?
self.bundle
self.app.fileSystem
app.io
[NSBundle
mainBundle]
What's the difference between NSArray and NSMutableArray?
NSMutableArrayʼs
contents can not be modified once itʼs been created whereas a NSArray can be
modified as needed
NSArray is
an abstractClass class and NSMutableArray is a protocol
NSArrayʼs
contents can not be modified once itʼs been created whereas a NSMutableArray
can be modified as needed
NSArray has
a limited capacity of 256 items where as NSMutableArray is unlimited
Which of the following keyboard shortcuts will run your app on the simulator?
Command-R
Command-G
Command-A
Command-P
What file contains configuration data for the app?
config.m
Main.m
Info.plist
AppDelegate.h
What is a delegate?
A
delegate is a variable
A delegate
holds the type of data a variable stores
A
delegate allows one NSObject to send messages to another NSObject, and listen
to those messages
A delegate
is a UIView
What function is called for each cell in a Table View?
viewWillLoad
cellDidAppear
cellForRowAtIndexPath
viewDidLoad
True or False: The main thread handles touch inputs
True
False
When using ARC, how do you destroy an object in Objective C?
Set
the variable that points at it to 1
All of these
Set the
variable that points at it to 0
Set
the variable that points at it to nil
True or False: A Collection View is another name for a tableView
False
True
What is the name of the type of SQL Database that iOS Supports?
SQL
NoSql
MySql
SQLite
When do you use the "assign" value for a property?
On
strings
On arrays
and dictionaries
Never. It
should always be either: atomic, nonatomic, strong or weak
For
primitive values such as BOOLs or NSIntegers
What do you use to expose preferences for your app in the Settings section of the device?
Settings.bundle
settings.m
NSSetting
Variables.bundle
What class supports the sharing of small amounts of data such as strings or dates to iCloud?
NSUrlConnection
NSOperation
NSUbiquitousKeyValueStore
What methods should you call when you add a children view controller?
-
(void)removeFromParentViewController
-
(void)removeFromSuperview
-
(void)addChildViewController:(UIViewController *)childController
-
(void)addSubview:(UIView *)view
How can you make the following code display with rounded corners? UIView *rectView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 100, 100)]; rectView.backgroundColor = [UIColor redColor]; rectView.layer.cornerRadius = 8; [self.view addSubview:rectView];
[rectView
drawRect:rectView.bounds];
rectView.roundedCornersVisible
= YES;
[rectView
setNeedsDisplay];
rectView.layer.masksToBounds
= YES;
Which of the following statements is TRUE?
When
using Grand Central Dispatch your app is assigned three Serial dispatch queues
When
using Grand Central Dispatch you can create as many serial dispatch queues as
you want
When using
Grand Central dispatch only three Serial dispatch queues can operate
concurrently
(none of
these are correct)
What are the two types of predicates?
Comparison
and Compound predicates.
Expression
and Operator predicates
Filter and
exclusion predicates
What flag prevents the device from turning off wifi if your app is running?
NSWifi
UIRequiresPersistentWiFi
UINetworkFlag
Airplane
Mode
Which is intended for storing small amount of sensitive data that are specific to your app like encrypted container and other secrets?
All
the above
None of the
above
Setting.bundle
info.plist
Keychain
What is a SEL?
A
pointer to a method
The C type
of a class
The
C type of a message selector
A selection
Which statement is NOT true of notifications?
Objects
register with a notification center to receive notifications
Notifications
are identified by the name instance method
Notifications
must be registered on the App Delegate
Notifications
are used to broadcast messages to possibly several recipients unknown from the
sender
Which of the follow statements is TRUE of the use of categories?
A
category can only be declared for abstract classes.
The syntax
to declare a category uses the @protocol keyword.
The
compiler synthesises any instance variable or property accessor methods for the
category.
You
can also use categories to split the implementation of a complex class across
multiple source code files.
In Objective C, what class will allow you to use one or more blocks concurrently?
NSConcurrency
NSConcurrentBlock
NSBlock
NSBlockOperation
Which of the following lines of code will cause a run time crash?
NSDictionary
*dict = [NSMutableDictionary dictionary];
NSArray
*array = [NSArray arrayWithObject:nil];
NSNumber *num
= [NSNumber numberWithInt:[NSNumber numberWithInt:1]];
NSArray
*array = @[ @"1", @"1", @"2", @"YES" ];
In Core Data, what is the object representation of a record called?
NSManagedObjectModel
NSEntityDescription
NSManageObjectContext
NSManagedObject
What would be the localized resource name for French?
fr.plist
fr.lproj
fr.local
french.lproj
True or False: You can weak link to an entire framework?
True
False
What is the preferred way to store paths to files?
NSURL
fileWithPath
NSSystemResource
NSFile
True or False? An object with at least one owner can be destroyed.
False
True
What is a persistent object store?
It
is retained database objects
It is the
relationships between tables in your data
It is the
schema for your object
It
represents an external file of persisted data.
True or False: You can use %@ to specify a dynamic property in Objectve C.
False
True
How can you temporarily disable layer actions in a Core Animation?
Using
the CAStopAnimation class
Using
the CATransaction class
Using the
CAStop class
Using the
CAExit class
What happens if you use fgets and do not give it a size smaller than the buffer?
It
will use the size of the object as its size
It
will overwrite the data past the size
None of
these
It will
clip its size automatically
This code doesn't do much, but which line will call the + (void)initialize method on the class SomeClass 1. - (void)doSomething 2. { 3. [SomeClass someClassMethod]; 4. SomeClass *obj = [[SomeClass alloc] init]; 5. NSString *descriptionString = [obj getNewString]; 6. }
line
4
line 1
line 5
line
3
What protocol is used to create an action object?
NSAction
CAAction
None of
these
CoreAnimation
In which scenario should you use an NSDictionary over an NSArray?
When
insertion time should be fast
When
item retrieval should be fast and in constant time
When
storing literals
It does't
matter, they're both data structures and can be used interchangeably
In Core Data, what is the name of the object representation for the database schema?
NSManagedObject
NSEntityDescription
NSManageObjectContext
NSManagedObjectModel
In Objective C, which of the following is group of objects that can be visualized as a physical set of frames?
The
set
The
stack
The frame
The heap
Which instrument would be most suited to debug whether a view is drawn from cache or redrawn?
Core
Animation
Time
Profiler
Zombies
Open GL ES
Driver
Which of the following is true?
A
class cannot be declared as abstract
Instance
variables must begin with underscore
A class
cannot implement more than one protocol
Instance
variables have to be declared in the header file containing the class definition
The app is in the background but not executing code. What State App is it in?
None
of above
InActive
Suspended
Terminated
Background
True or False: In Objective C, all instance methods are accessors.
TRUE
False
What is the effect of using 'weak' in the following @property definition: @property (nonatomic, weak) SomeClass *responder; ?
The
responder object is not retained and the pointer is set to nil when the object
is destroyed
The
responder object is not retained and the pointer will point to free memory when
the object is destroyed
The
responder object is retained and the pointer is set to nil when the object is
destroyed
The
responder object is retained and the pointer will point to free memory when the
object is destroyed
how can we return multiple values from function?
void*
return
multiple(...)
tuple
not possible
When adding objects to NSMutableDictionary, the key...
Can
be any object
Must be
wither an NSString or an NSNumber
Must
conform to the NSCopying protocol
Must be a
string literal
What class can implement Document Objects?
NSArray
NSDocument
UIDocument
NSUrl
Which of the following methods is used to deallocate all the noncritical custom data structure associated with your view controller?
None
of above
didReceiveMemoryWarning
viewDidUnload
viewWillUnload
dealloc
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