jquery mobile jump start

jQuery Mobile Jump Start

Troy Miles aka @therockncoder

Saturday, June 15, 13

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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 #1Semantic 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 #2Create 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

• 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 #3Getting Data

• Starting from exercise #3

• Make a call to YP 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 #4Getting more data

• Starting from exercise #4

• Make more calls to the YP 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 #5Creating 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 #6Smooth 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 #7Using 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 #8Getting 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 (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 #9Displaying 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 #10Annotating 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 #11Making a Responsive Design

• Modify the code to show the map next to the listview when there is sufficient width

Summary

• Responsive Design is difficult

• A solution for one web site will not necessarily work for another

• 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 #12Uploading 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 #13Charting 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

• 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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