603848771-Lecture-1-Intro-to-Flutter-and-Dart.pptx

Duration: 65 min High School Grades: 9 - 12 CCSS, NGSS
Mobile Application Development
Introduction to Flutter & Dart
Instructor: Engr. Farhan Ghafoor
Associate Professor, Software Engineering Dept, CoE

Technical Overview
What is flutter?
An app SDK capable of providing high performance applications for
 iOS & Android,
 Web (Hummingbird – work in progress)
 Even Desktop (Work in progress).
High Performance Applications that will have same natural feel as if it was written on the same
platform
Apps are written in Dart language

What is Dart?
An object-oriented language.
Supports Ahead-of-Time (AOT) and Just-in-Time (JIT) compilation
C-style syntax
Statically Type

Dart Basics
Dart Pad Editor:
 https://dartpad.dev/?
Functions
Variables and Values
Types
Classes

Mobile App Architecture
Presentation Layer (PL)
• This Layer focuses on UI Components (View and Controller)
• Defines the way, the mobile app will present itself in front of the end user
• On this Layer, just focus on features and their locations

Business Layer (BL)
Focuses on Business logic
Includes workflow, Business components
Service Layer and Domain Layer
 Service Layer: Defines a common set of application functions that will be available to the client and end users
 Domain Layer: Focuses on the domain specific problems

Data Layer (DL)
 It’s the final layer!
 data access components (DAC),
 Data Helpers/Utilities
 Service Agents
 These three components control the — Persistence Layer(Backend) / Network Call
Since now we know the basic architecture, here comes the question!
Why we want to use flutter ?
Or why we should use it ?

Why Learn Flutter and Dart?
Benefits associated with:
It’s highly productive! It is Perfect for an MVP!
Develops iOS and Android applications from single code base
Prototype and iterate easily: — Experimental feature can reflect instantly by hot
reload, fix crashes and continue debugging from where the app left off
Creates beautiful, highly customized user experiences (has its own rendering
engine)
Consistent UIs across devices and manufacturers
Superb performance

Benefits associated with Flutter
Material Design and Cupertino available for iOS widgets
Resembles React Native
No need to use a JavaScript bridge, which improves app startup times and
overall performance.
Once your UI works, it just works. And keeps working.
Manufacturers / OS versions / different devices can’t break it
Dart achieves this thanks to Ahead-of-Time (AOT), compilation. Dart also
makes use of Just-in-Time, or JIT, compilation.

Flutter includes:
 A modern react-style framework,
 A 2-D rendering engine,
 Ready-to use widgets, and
 Development tools.
Flutter basically provides all those components which are required to build a
 Highly interactive and
 Personalized application for fast development
Especially Android APIs require a lot of ceremony for simple things
 Flutter was able to start from scratch and avoid previously made pitfalls

Platform SDKs (Android and IOS)

Flutter vs React Native
Base image from: https://speakerdeck.com/passsy/flutter-60-fps-ui-of-the-future
Our cross-platform code Native land
● Also fast performance here, however:
○ Expensive to travel to
● We can’t afford to go here too often, just like we can’t
afford beach vacations every week
● Everything in our control
● Things we do here have fantastic performance
and are cheap
● We should stay here as much as possible

Flutter - Native Plugins
Allow access to every native platform API
 Bluetooth, geolocation, sensors, fingerprint, camera, etc.
Both official and community-driven plugins available
Some plugins missing or in early stages
 There’s a community-driven geolocation plugin with really limited API
 There’s a community-driven Bluetooth plugin that doesn’t work with iOS just yet
If a plugin for your use case doesn’t exist, you’ll have to make it yourself
This is where other frameworks like React Native & Xamarin currently shine and Flutter takes the loss
 Situation expected to be solved with time

Introduction to Widgets
Flutter widgets are built using a modern framework that takes inspiration from React.
Building blocks of UI in Flutter
The whole app is a Widget. A screen is a Widget that contains Widgets.
What is a widget? Widgets can be compared to LEGO blocks.
Advanced widgets are made by combining basic widgets.
Widgets describe what their view should look like given their current configuration and state.

Widgets
The whole app is a Widget. A screen is a Widget that contains Widgets.
Can represent
UI element, such as Text, Button, BottomNavigationBar, TextField, etc.
Layout element, such as Padding, Center, Stack, Column, etc.
Completely new screen (Activity/ViewController equivalent)

Widgets
Each widget is an immutable declaration of the user interface.
Widgets are configurations for different parts of the UI.
Placing the widgets together creates the widget tree
 Like an Architect draws a blue-print of a house.

Widgets
Widgets create a widget tree.
When a widget’s state changes,
 the widget rebuilds its description,
 Which the framework differentiates against the
previous description
 Why?
 To determine the minimal changes needed in the
underlying render tree to transition from one state to the
next.

Widget Catalog https://docs.flutter.dev/development/ui/widgets

Widget Catalog – Material Design Widgets
https://docs.flutter.dev/develop
ment/ui/widgets/material

Widgets
Flutter has widgets with:
Structuring elements such as a list, grid, text, and button
Input elements such as a form, form fields, and
keyboard listeners
Styling elements such as font type, size, weight, color,
border, and shadow
to lay out the UI such as row, column, stack, centering,
and padding
Interactive elements that respond to touch,
gestures, dragging, and dismissible
Animation and motion elements such as
hero animation, animated container,
Animated crossfade, fade transition,
rotation, scale, size, slide, and opacity
Elements like assets, images, and icons
Widgets that can be nested together to
create the UI needed
Custom widgets you can create yourself

Flutter architectural overview
Flutter is a cross-platform UI toolkit
It is designed to allow code reuse across operating systems such as iOS and Android, while
also allowing applications to interface directly with underlying platform services.
To enable developers to deliver high-performance apps that feel natural on different platforms,
embracing differences where they exist while sharing as much code as possible.

During development:
Flutter apps run in a VM that offers stateful hot reload of changes without needing a full
recompile.
For release:
Flutter apps are compiled directly to machine code, whether Intel x64 or ARM instructions,
Or to JavaScript if targeting the web.
The framework is open source, with a permissive BSD license,
Has a thriving ecosystem of third-party packages that supplement the core library functionality.

This overview is divided into a number of sections:
1. The layer model: The pieces from which Flutter is constructed.
2. Reactive user interfaces: A core concept for Flutter user interface development.
3. An introduction to widgets: The fundamental building blocks of Flutter user interfaces.
4. The rendering process: How Flutter turns UI code into pixels.
5. An overview of the platform embedders: The code that lets mobile and desktop OSes execute Flutter
apps.
6. Integrating Flutter with other code: Information about different techniques available to Flutter apps.
7. Support for the web: Concluding remarks about the characteristics of Flutter in a browser
environment.

1. Architectural layers
Designed as an extensible, layered
system.
Exists as a series of independent libraries
that each depend on the underlying layer.
No layer has privileged access to the layer
below
Every part of the framework level is
designed to be optional and replaceable.

1. Architectural layers - Embedder
To the underlying OS, Flutter applications
are packaged in the same way as any other
native application.
A platform-specific embedder provides an
entry point; coordinates with the underlying
operating system for access to services like
 rendering surfaces,
 accessibility, and
 Input
 manages the message event loop.
 The embedder is written in a language that is
appropriate for the platform:
 Java and C++ for Android,
 Objective-C/Objective-C++ for iOS and macOS,
 C++ for Windows and Linux.

1. Architectural layers - Embedder
Using the embedder,
 Flutter code can be integrated into an existing
application as a module,
 Or the code may be the entire content of the
application.
Flutter includes a number of embedders for
common target platforms, but
other embedders also exist.

1. Architectural layers – Flutter Engine
At the core of Flutter is the Flutter engine,
mostly written in C++
Supports the primitives necessary to support all
Flutter applications.
Responsible for rasterizing composited scenes
whenever a new frame needs to be painted.
Provides the low-level implementation of
Flutter’s core API, including:
 Graphics (through Skia),
 Text layout, File and network I/O,
 Accessibility support,
 Plugin architecture, and
 A Dart runtime and compile toolchain.

1. Architectural layers – Flutter Engine
The engine is exposed to the Flutter
framework through dart:ui
dart:ui wraps the underlying C++ code in
Dart classes.
This library exposes the lowest-level
primitives, such as:
 Classes for driving input
 Graphics
 Text rendering subsystems

1. Architectural layers – Flutter Framework
Developers interact with Flutter through the
Flutter framework,
Provides a modern, reactive framework
written in the Dart language.
Includes a rich set of platform, layout, and
foundational libraries, composed of a series
of layers.

1. Architectural layers – Flutter Framework
Working from the bottom to the top, we have:

1. Architectural layers – Conclusion
Flutter framework is relatively small
Many higher-level features are implemented as packages, including
 Platform plugins like camera and webview,
 Platform-agnostic features like characters, http, and animations that build upon the core Dart and Flutter
libraries.
Some of these packages come from the broader ecosystem, covering services like
 in-app payments,
 Apple authentication, and
 Animations.

Q&A
Mobile Application Development - Flutter

Thank you
Mobile Application Development - Flutter

603848771-Lecture-1-Intro-to-Flutter-and-Dart.pptx

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