Stanford CS193p Developing Applications for iOS Spring 2016 CS193p - - PowerPoint PPT Presentation

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Apr 17, 2023 164 likes •524 views

Stanford CS193p Developing Applications for iOS Spring 2016 CS193p Spring 2016 Today MVC Object-Oriented Design Pattern Continuation of Calculator Demo Computed Properties, MVC, Laying out the UI to work with different devices CS193p Spring

SLIDE 1

CS193p Spring 2016

Stanford CS193p

Developing Applications for iOS Spring 2016

SLIDE 2

CS193p Spring 2016

Today

MVC

Object-Oriented Design Pattern

Continuation of Calculator Demo

Computed Properties, MVC, Laying out the UI to work with different devices

SLIDE 3

CS193p Spring 2016

Controller

MVC

Model View

Divide objects in your program into 3 “camps. ”

SLIDE 4

CS193p Spring 2016

Controller

MVC

Model View

Model = What your application is (but not how it is displayed)

SLIDE 5

CS193p Spring 2016

Controller

MVC

Model View

Controller = How your Model is presented to the user (UI logic)

SLIDE 6

CS193p Spring 2016

Controller

MVC

Model View

View = Your Controller’ s minions

SLIDE 7

CS193p Spring 2016

Controller

MVC

Model View

It’ s all about managing communication between camps

SLIDE 8

CS193p Spring 2016

Controller

MVC

Model View

Controllers can always talk directly to their Model.

SLIDE 9

CS193p Spring 2016

Controller

MVC

Model View

utlet

Controllers can also talk directly to their View.

SLIDE 10

CS193p Spring 2016

Controller

MVC

Model View

utlet

The Model and View should never speak to each other.

SLIDE 11

CS193p Spring 2016

Controller

MVC

Model View

?

utlet

Can the View speak to its Controller?

SLIDE 12

CS193p Spring 2016

Controller

MVC

Model View

utlet

Sort of. Communication is “blind” and structured.

SLIDE 13

CS193p Spring 2016

Controller

MVC

Model View

utlet

target

The Controller can drop a target on itself.

SLIDE 14

CS193p Spring 2016

Controller

MVC

Model View

action

utlet

target

Then hand out an action to the View.

SLIDE 15

CS193p Spring 2016

Controller

MVC

Model View

action

utlet

target

Then hand out an action to the View.

SLIDE 16

CS193p Spring 2016

Controller

MVC

Model View

action

utlet

target

The View sends the action when things happen in the UI.

SLIDE 17

CS193p Spring 2016

Controller

MVC

Model View

action

utlet

should will did

target

Sometimes the View needs to synchronize with the Controller.

SLIDE 18

CS193p Spring 2016

Controller

MVC

Model View

action delegate

utlet

should will did

target

The Controller sets itself as the View’ s delegate.

SLIDE 19

CS193p Spring 2016

Controller

MVC

Model View

action delegate

utlet

should will did

target

The delegate is set via a protocol (i.e. it’ s “blind” to class).

SLIDE 20

CS193p Spring 2016

Controller

MVC

Model View

action delegate

utlet

should will did

target

Views do not own the data they display.

SLIDE 21

CS193p Spring 2016

Controller

MVC

Model View

action delegate

utlet

should will did

target

count data at

So, if needed, they have a protocol to acquire it.

SLIDE 22

CS193p Spring 2016

Controller

MVC

Model View

action delegate

utlet

d a t a s

r c e

should will did

target

count data at

Controllers are almost always that data source (not Model!).

SLIDE 23

CS193p Spring 2016

Controllers interpret/format Model information for the View.

Controller

MVC

Model View

action delegate

utlet

d a t a s

r c e

should will did

target

count data at

SLIDE 24

CS193p Spring 2016

Controller

MVC

Model View

action

?

delegate

utlet

d a t a s

r c e

should will did

target

count data at

Can the Model talk directly to the Controller?

SLIDE 25

CS193p Spring 2016

Controller

MVC

Model View

action delegate

utlet

d a t a s

r c e

should will did

target

count data at

No. The Model is (should be) UI independent.

SLIDE 26

CS193p Spring 2016

Controller

MVC

Model View

action delegate

utlet

d a t a s

r c e

should will did

target

count data at

So what if the Model has information to update or something?

SLIDE 27

CS193p Spring 2016

Controller

MVC

Model View

action Notification & KVO delegate

utlet

d a t a s

r c e

should will did

target

count data at

It uses a “radio station”-like broadcast mechanism.

SLIDE 28

CS193p Spring 2016

Controller

MVC

Model View

action Notification & KVO delegate

utlet

d a t a s

r c e

should will did

target

count data at

Controllers (or other Model) “tune in” to interesting stuff.

SLIDE 29

CS193p Spring 2016

A View might “tune in,” but probably not to a Model’ s “station. ”

Controller

MVC

Model View

action Notification & KVO delegate

utlet

d a t a s

r c e

should will did

target

count data at

SLIDE 30

CS193p Spring 2016

Controller

MVC

Model View

action Notification & KVO delegate

utlet

d a t a s

r c e

should will did

target

count data at

Now combine MVC groups to make complicated programs ...

SLIDE 31

CS193p Spring 2016

Controller

MVC

Model View

action Notification & KVO delegate

utlet

d a t a s

r c e

should will did

target

count data at

Now combine MVC groups to make complicated programs ...

SLIDE 32

CS193p Spring 2016

MVCs working together

SLIDE 33

CS193p Spring 2016

MVCs not working together

SLIDE 34

CS193p Spring 2016

Demo

Calculator continued …

“Computed” properties (instance variables which are computed rather than stored) switch Functions as types Closure syntax for defining functions “on the fly” UIStackView