jQuery Mobile Jump Start

jQuery Mobile
Jump Start
Troy Miles aka @therockncoder
Saturday, June 15, 13

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@therockncoder

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https://github.com/Rockncoder

Before We Begin
• This class will move fast
• Don’t worry if you don’t complete an
exercise
• The exercises and solutions are available
for download
• All slides are available for download

What Are Going To
Do?
We are going to learn about jQuery Mobile by examining a
working application.We aren’t going to decompose each
line of code, instead we will examine each major area of
functionality.

Coffee+Coffee
• Listview
• Location/Maps
• Ajax
• Templates

Today’s Agenda
• 0830-0900 Setup
• 0900-0930 HTML Overview
• 0930-1000 JavaScript Overview
• 1015-1030 Morning Break
• 1000-1030 Ajax pt. 1
• 1045-1115 Ajax pt. 2

Today’s Agenda
• 1115-1145 Listviews
• 1145-1215 Templates
• 1215-1245 Lunch
• 1245-1345 Location & Maps
• 1400-1445 Responsive Design
• 1445-1515 Media & Charts

“You have to learn to fake
the funk before you can
begin to make the funk.”

HTML5 Overview
• Fast Facts
• Best Practices
• Exercise - Creating a semantic SPA
• Summary

Fast Facts
• HTML5 not ofﬁcial but in wide use
• Well supported by smart phones: iPhone,
Android, Blackberry, and WP8
• W3C analyzed millions of web pages to
decide on new semantic tags
• SPA - single page application

Best Practices
• Use semantic tags for clarity
• Place multiple pages together for speed
• Use page transitions for a better UX

Exercise #1
Semantic SPA
• Start with the exercise folder
• Add a second JQM page
• Use transitions to smooth page change

Summary
• The new semantic tags in HTML5 increase
clarity
• jQuery Mobile includes attributes to
improve app look and feel

“Java is to JavaScript as
Car is to Carpet.”

JavaScript Overview
• Fast Facts
• The Power Trio
• Events
• Best Practices
• Exercise - Create page code
• Summary

Fast Facts
• Created by Brendan Eich of Netscape
• Originally named LiveScript, but renamed
for marketing purposes
• Based on Self and Scheme languages, but
not C

The Power Trio
• Objects
• Functions
• Closures

Objects
• Are associative arrays or dictionaries
consisting of key/value pairs
• The key can be ANY string
• Can be modiﬁed at run-time
• No difference between dot and bracket
notations

Functions
• Are ﬁrst-class entities
• They are objects themselves and can have
properties and methods
• The provide the primary method of
information hiding
• Can be nested and passed as parameters

Closures
• A very tough concept to grasp
• A closure is a special kind of object that
combines two things: a function, and the
environment in which that function was
created.

Events
• A loosely couple way of component
communication
• Receive or handle events
• Transmit or trigger events
• In jQuery .on() and .off() are preferred

Best Practices
• Minimize the use of global memory
• Wrap code in functions to protect it
• Load JS ﬁles last for speed*
• Use events to avoid tight coupling

Exercise #2
Create Page Code
• Start from the exercise #2 code
• Create code to hook events for both page
1 and 2

Summary
• JavaScript in the browser is a very dirty
environment
• Apps must be pro-active in order to
function well
• Always write your code in a structured way

Why not jQuery 2.0?
• jQuery 2.0 is available and is smaller and
faster since it no longer supports IE
versions 6, 7, and 8. Yet we use version 1.91
in the app, why? The jQuery Mobile team
has not yet upgraded JQM to support it.

Ajax pt. 1
• Fast Facts
• jQuery ajax()
• Promise
• Data Formats
• Exercise - Getting data from the server
• Summary

Fast Facts
• The web designed to load complete HTML
pages
• Microsoft created XMLHTTP object in 1998
• Mozilla based their XMLHttpRequest object
on it in 2000
• The XMLHttpRequest object became a
defacto standard

.ajax()
• Before the introduction of Prototype &
jQuery in 2006 communication with the
server was browser speciﬁc
• Performs an async HTTP request
• .ajax(url, [settings])

.promise()
• Returns a Promise object that is resolved
once all actions complete
• Considered easier to ready than callbacks

Data Formats
• There two standard data formats:
• JSON - JavaScript Object Notation
• XML - eXtensible Markup Language
• JSON is the lighter of the two

JSON
• Created by Douglas Crockford in 2001
• JSON.stringify to serialize
• JSON.parse to deserialize
• Ofﬁcially only double quotes supported

Best Practices
• Always be prepared for failure
• Prefer chunky over chatty
• Prefer JSON over XML
• Use double quotes in JSON

Exercise #3
Getting Data
• Starting from exercise #3
• Make a call toYP API
• Use an alert or console.log to display
results

Summary
• Its ability to do cross-browser Ajax is one
of jQuery’s most popular features
• Ajax data to/from RESTful web services is
very popular

Ajax pt. 2
• HTTP Trafﬁc Watching
• Chrome & Fiddler
• Exercise - Paging, Getting more data
• Summary

HTTP Trafﬁc Watching
• Issues with Ajax often cause bugs
• Their async nature makes can make ﬁxing
these bugs challenging
• There are tools to help

Chrome & Fiddler
• Chrome includes tools to watch network
trafﬁc (lightweight)
• Fiddler a free tool from Telerik is also
available (super)
• Fiddler is only available for the PC

Exercise #4
Getting more data
• Starting from exercise #4
• Make more calls to theYP API which
request more data
• Again use alert or console.log to display
results

Summary
• Debugging Ajax issues can be tough but
there are tools to help
• Often the amount of data available exceeds
that which can be easily handled

Listviews
• Fast Facts
• Best Practices
• Vertical Scrolling
• Exercise - Creating list from data
• Summary

Fast Facts
• Listviews are coded as either HTML
unordered (ul) or ordered (ol) lists
• Can be used as menus, settings or simply
display a list of items

Vertical Scrolling
• JQM supports vertical scrolling as does any
other web site
• Can also ﬁx the position of the header and
footer

Exercise #5
Creating a Listview
• Start with exercise #5
• Finish the listview generation code
• Remember to call the refresh method

Summary
• JQM out of the box supports vertical
scrolling
• The end result is less than app-like however

iScroll
• Fast Facts
• Best Practices
• Exercise - Implement pull to refresh
• Summary

Fast Facts
• iScroll4 created by Matteo Spinelli
• Source code is MIT Licensed
• Works by using CSS3 transformation
• Number of scroll regions only limited by
memory

Best Practices
• Release no longer needed iScrolls with the
destroy() method

Exercise #6
Smooth Scrolling
• Finished the smooth scrolling method
• If you have trouble, look at the working
“cc” app

Summary
• Smooth scrolling improves both UI and UX
• It is relatively easy to replace traditional
HTML scrolling

Templates
• Fast Facts
• Handlebars
• Best Practices
• Exercise - Rewrite the code to use
templates
• Summary

Fast Facts
• Mixing HTML with JavaScript violates
separation of concerns
• Templating engines allow for the inclusion
of HTML which can be modiﬁed easily
• HTML by deﬁnition does not operate on
unknown tags

Handlebars.js
• There are many of templating engines
• Handlebars.js works on both the client and
the server
• The project is maintain by the same team
as Ember.js

Best Practices
• HTML is content
• CSS is presentation
• JavaScript is behavior
• Separation of Concerns (SOC) states not
to mix any of the three

Exercise #7
Using Templates
• Start from exercise #7
• Replace the use of JS strings with a
template

Summary
• Using templates keeps us from violating
separation of concerns
• The handlebars templates are easy for both
engineers and designers to work with

Geolocation
• Fast Facts
• The Geolocation Object
• Best Practices
• Exercise - Get location
• Summary

Fast Facts
• Not actually part of HTML5
• User must grant web site access to the
geolocation data
• Can be a signiﬁcant drain on batteries
• Can take a signiﬁcant amount of time
before location async return

The Geolocation Object
• Part of the navigator object, which has no
ofﬁcial standard
• Three methods: getCurrentPosition(),
watchPosition(), clearWatch()

Best Practices
• People have just concerns about location
privacy
• Provide an alternative if possible
• Gracefully fail it not able to continue
• Remember to clear unneeded
watchPositions

Exercise #8
Getting Location
• Starting with exercise #8
• Use a console.log to display the current
latitude and longitude

Summary
• Geolocation is support by most current
browsers, mobile and desktop
• Power used Geolocation can drain power
and tax CPU

Maps
• Maps (Google Maps)
• Exercise - Display our current location
• Annotating Maps
• Exercise - Displaying cafe location
• Summary

Google Maps
• There are many publicly available map
providers
• Google was chosen because of its
accuracy, simplicity, and cost (free)
• To use simply include a ﬁle, specify a div,
and call the draw map code

Exercise #9
Displaying a Map
• The Maps include ﬁle is present
• The map div is displayed on the page
• Write the code to make the map appear

Map Annotation
• Markers identify locations on the map
• You can use Google’s markers or your own
• Markers can have click events

Exercise #10
Annotating a Map
• Place a maker on the map at:
• latitude = 33.8226203918457
• longitude= -118.331848144531

Summary
• Most users expect to see a map wherever
location information is displayed
• Google Maps is the most popular map
provider (75% of web sites)

Responsive Design
• Fast Facts
• Phone vs Tablet
• Grids, Divs, and Tables
• Exercise - Make display responsive
• Summary

Fast Facts
• Responsive design means supporting
multiple device resolutions from a single
application
• JQM added the Grid object to support
responsive design
• JQM 1.3.0 added tables

Best Practices
• Be careful of one size ﬁts all solutions
• The needs of your mobile user maybe
different than those on desktop
• Always keep bandwidth restrictions in mind

Exercise #11
Making a Responsive Design
• Adjust the values of the media queries to
see how the app adjust

Summary
• Responsive Design is difﬁcult and must be
thoroughly planned
• A solution for one web site will not
necessarily work for another

Media
• Fast Facts
• Taking a picture (yes, from a mobile
browser)
• Exercise - Upload a picture to a server
• Summary

Fast Facts
• Modern smart phones treat the input
type=”ﬁle” as the camera
• Can take picture or video or choose from
photo album
• The real work is done on the server

Taking and Uploading a
Picture
• Must turn off JQM’s Ajax with data-
ajax=”false”
• Use a input type=ﬁle with form post with
enctype=”multipart/form-data”

Exercise #12
Uploading a Picture
• Complete form tag for upload
• You will not actually be able to submit the
photo since that requires a server

Summary
• Many mobile browser support photo
upload, but not all
• Can upload photo and video but keep in
mind how much memory is required
• Can also choose from photos in the user’s
album

Charts
• Fast Facts
• jqPlots
• Exercise - Create a chart from hours of
operation
• Summary

Fast Facts
• Humans understand visual faster than
written
• Charts are a standard way to render
numeric data
• There are lots of charting solutions for the
web

jqPlot
• An open source project by Chris Leonello
• A jQuery widget
• Supports its own plug-in
• Rendered completely on the client

Best Practices
• Charts are computationally expensive to
render
• It is possible to render charts dynamically,
but not recommended

Exercise #13
Charting Data
• Start from exercise #13
• Implement bar chart to display hours of
operation of coffee shops

Summary
• jqPlot is free and easy use charting solution

Links
• jquerymobile.com
• jquery.com
• cubiq.org/iscroll-4
• jqplot.com
• http://handlebarsjs.com/
• callbackhell.com
• garann.github.io/template-chooser/

My Links
• @therockncoder
• https://github.com/Rockncoder
• http://youtube.com/rockncoder
• http://slideshare.net/rockncoder

Course Summary
• When in doubt follow best practices
• Build a Coffee+Coffee app of your own
• Still lots we haven’t covered

jQuery Mobile Advance
• MV* Frameworks
• Responsive Design
• Deep Templating
• Memory Management
• Unit Testing
• Nag Phillip until he schedules it!

jQuery Mobile Jump Start

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