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Lecture 2 Slides - Apple Inc. · UIStackView First peek at Autolayout (stick things to the edges)...
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CS193p Winter 2017 Stanford CS193p Developing Applications for iOS Winter 2017
Transcript of Lecture 2 Slides - Apple Inc. · UIStackView First peek at Autolayout (stick things to the edges)...
CS193pWinter 2017
Stanford CS193pDeveloping Applications for iOS
Winter 2017
CS193pWinter 2017
TodayMVC
Object-Oriented Design Pattern
Continuation of Calculator DemoComputed Properties, MVC, Laying out the UI to work with different devices
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Controller
MVC
Model View
Divide objects in your program into 3 “camps.”
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Controller
MVC
Model View
Model = What your application is (but not how it is displayed)
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Controller
MVC
Model View
Controller = How your Model is presented to the user (UI logic)
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Controller
MVC
Model View
View = Your Controller’s minions
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Controller
MVC
Model View
It’s all about managing communication between camps
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Controller
MVC
Model View
Controllers can always talk directly to their Model.
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Controller
MVC
Model View
outlet
Controllers can also talk directly to their View.
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Controller
MVC
Model View
outlet
The Model and View should never speak to each other.
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Controller
MVC
Model View
?outlet
Can the View speak to its Controller?
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Controller
MVC
Model View
outlet
Sort of. Communication is “blind” and structured.
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Controller
MVC
Model View
outlet
target
The Controller can drop a target on itself.
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Controller
MVC
Model View
action
outlet
target
Then hand out an action to the View.
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Controller
MVC
Model View
action
outlet
target
Then hand out an action to the View.
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Controller
MVC
Model View
action
outlet
target
The View sends the action when things happen in the UI.
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Controller
MVC
Model View
action
outlet
should
will did
target
Sometimes the View needs to synchronize with the Controller.
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Controller
MVC
Model View
action
delegate
outlet
should
will did
target
The Controller sets itself as the View’s delegate.
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Controller
MVC
Model View
action
delegate
outlet
should
will did
target
The delegate is set via a protocol (i.e. it’s “blind” to class).
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Controller
MVC
Model View
action
delegate
outlet
should
will did
target
Views do not own the data they display.
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Controller
MVC
Model View
action
delegate
outlet
should
will did
target
countdata at
So, if needed, they have a protocol to acquire it.
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Controller
MVC
Model View
action
delegate
outlet
data source
should
will did
target
countdata at
Controllers are almost always that data source (not Model!).
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Controllers interpret/format Model information for the View.
Controller
MVC
Model View
action
delegate
outlet
data source
should
will did
target
countdata at
CS193pWinter 2017
Controller
MVC
Model View
action
? delegate
outlet
data source
should
will did
target
countdata at
Can the Model talk directly to the Controller?
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Controller
MVC
Model View
action
delegate
outlet
data source
should
will did
target
countdata at
No. The Model is (should be) UI independent.
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Controller
MVC
Model View
action
delegate
outlet
data source
should
will did
target
countdata at
So what if the Model has information to update or something?
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Controller
MVC
Model View
action
Notification& KVO
delegate
outlet
data source
should
will did
target
countdata at
It uses a “radio station”-like broadcast mechanism.
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Controller
MVC
Model View
action
Notification& KVO
delegate
outlet
data source
should
will did
target
countdata at
Controllers (or other Model) “tune in” to interesting stuff.
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A View might “tune in,” but probably not to a Model’s “station.”
Controller
MVC
Model View
action
Notification& KVO
delegate
outlet
data source
should
will did
target
countdata at
CS193pWinter 2017
Controller
MVC
Model View
action
Notification& KVO
delegate
outlet
data source
should
will did
target
countdata at
Now combine MVC groups to make complicated programs ...
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MVCs working together
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MVCs not working together
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DemoCalculator continued …
MVCstruct vs. class (mutating, etc.)public versus private APImore examples of OptionalDictionary<KeyType,ValueType>enumassociated valuesswitchFunctions as typesClosure syntax for defining functions “on the fly”UIStackViewFirst peek at Autolayout (stick things to the edges)
![Hopper - CocoaHeads€¦ · Legit every day uses for Hopper • Do I need to check for changes before calling [some UIKit object setter] • Is it really worth it to use -[UIStackView](https://static.fdocuments.us/doc/165x107/5f776acca72d5c550b6cf4cf/hopper-cocoaheads-legit-every-day-uses-for-hopper-a-do-i-need-to-check-for-changes.jpg)
