cse439 lecture4 1-29-20todd/cse439/cse...2020/01/29 · Architecting Your App for Multiple Windows 18 1/29/20 10 19Extensible Networking Platform-CSE 439 –Mobile Application Development

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Extensible Networking Platform 11 - CSE 439 – Mobile Application Development II

Announcement

• On Monday your February plan is due

• Please submit your plan to your Github Classroom

Repo by 11:59 PM on Monday evening

• Details regarding the February plan are on the

course website

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Today – Frontend/Backend Techniques

• Xcode Debugger

• AutoLayout Review

• SwiftUI

• App States

• More about backend and Firebase

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Let’s admit it...

Source: https://me.me/i/debug-properly-using-a-debugger-println-5f3a117e2b0d4228b775268ead9c0851

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Back to reality...debuggers are pretty awesome

• ...and it’s probably something you have to learn at some point

• Xcode uses LLDB debugger as its default debugging tools.

• According to its homepage:

• “LLDB is a next generation, high-performance debugger. It is built as

a set of reusable components which highly leverage existing libraries

in the larger LLVM Project, such as the Clang expression parser and

LLVM disassembler”.

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https://lldb.llvm.org/

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Debugging teaser demo

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Debugging Tutorial by Apple

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https://developer.apple.com/videos/play/wwdc2018/412/

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SwiftUI

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Swift UI

• Introduced in WWDC 19. A radically new and powerful way to code UI

• No storyboard anymore. All UI is codified using Swift

• Feels a little bit like React?

• We don’t require you to use this as it’s relatively new, but you are more

than welcome to try it.

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Resources to learn more about Swift UI

There is a series of SwiftUI tutorials by Apple available here that covers it very well:

Apple’s SwiftUI Tutorials

WWDC 19 Intro to SwiftUI

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SwiftUI teaser demo

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https://developer.apple.com/tutorials/swiftui/creating-and-combining-views


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App Life-Cycle

In iOS 13 and apps that support scenes:

Scene-Based Life-Cycle Events

Before iOS 13 or for apps that don’t support scenes:

App-Based Life-Cycle Events

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App-Based Life Cycle Events

For more information, check out Apple’s Managing Your App's Life Cycle

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https://developer.apple.com/documentation/uikit/app_and_environment/managing_your_app_s_life_cycle

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From Not-running to Inactive: App Launch Sequence

From Apple’s About the App Launch Sequence

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From Not-running to Inactive

application(_:willFinishLaunchingWithOptions:)application(_:didFinishLaunchingWithOptions:)

For more information, check out Apple’s Responding to the Launch of Your App

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https://developer.apple.com/documentation/uikit/app_and_environment/responding_to_the_launch_of_your_app/about_the_app_launch_sequence

https://developer.apple.com/documentation/uikit/app_and_environment/responding_to_the_launch_of_your_app

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Inactive And Active

For more information, check out Apple’s Preparing Your UI to Run in the Foreground

applicationDidBecomeActive(_:)viewWillAppear(_:)

applicationWillResignActive(_:)

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Inactive And Background

applicationDidEnterBackground(_:)

applicationWillEnterForeground(_:)

For more information, check out Apple’s Preparing Your UI to Run in the Foreground and Preparing Your UI to Run in the Background

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https://developer.apple.com/documentation/uikit/app_and_environment/scenes/preparing_your_ui_to_run_in_the_foreground


https://developer.apple.com/documentation/uikit/app_and_environment/scenes/preparing_your_ui_to_run_in_the_background

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UIScene

• Introduced in WWDC 19 as

another feature in iOS 13

• Features better support for

multiwindow

• Using UIScene, one app can have

two running instances at the

same time, like the one on the

left.For more information, check out WWDC 19 video Architecting Your App for Multiple Windows

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Relationship between App Delegate and Scene Delegate

For more information, check out WWDC 19 video Architecting Your App for Multiple Windows

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Scene-Based Life Cycle Events

For more information, check out Apple’s Managing Your App's Life Cycle

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Inactive And Active (Scene)

For more information, check out Apple’s Preparing Your UI to Run in the Foreground

sceneDidBecomeActive(_:)

sceneWillResignActive(_:)

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https://developer.apple.com/documentation/uikit/app_and_environment/managing_your_app_s_life_cycle


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Inactive And Background (Scene)

sceneDidEnterBackground(_:)

sceneWillEnterForeground(_:)

For more information, check out Apple’s Preparing Your UI to Run in the Foreground and Preparing Your UI to Run in the Background

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Backend

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https://developer.apple.com/documentation/uikit/app_and_environment/scenes/preparing_your_ui_to_run_in_the_background

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General Backend Notes• Even for mobile apps, it’s usually not sufficient to just have a database as your

backend.

• Sometimes you want to perform more complicated or intensive tasks than what

your database can handle.

• And you want to keep the frontend as lightweight as possible for better user

experience.

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Firebase cloud functions

• Powerful, lightweight backend functions

• Easy to implement and test; each function is usually a short snippet of

code.

• Integrates well with cloud messaging and other Firebase services.

• Available in both JavaScript and TypeScript.

• Firebase official docs: https://firebase.google.com/docs/functions

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Cloud function demo

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Firebase ML Kit

• Backend machine learning functions provided by Firebase

• Comes with a set of pre-trained model.

• Easy to use. Using each of them is like calling an API.

• Can also handle your own Tensorflow model.

• Docs: https://firebase.google.com/docs/ml-kit

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Other notes about backend• We think a combination of database, cloud functions and machine

learning kit can satisfy many needs for backend in the case of a mobile app.

• But if your app requires more backend support, you can develop fully fledged web apps to achieve that.

• Firebase is integrated into Google Cloud, so if you want to stay within it, Google App Engine is a great choice.

• For those of you who had 330, AWS is also a very popular platform.

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Documents

cse439 lecture4 1-29-20todd/cse439/cse...2020/01/29 · Architecting Your App for Multiple Windows 18 1/29/20 10 19Extensible Networking Platform-CSE 439 –Mobile Application Development