[JavaLand 2015] Developing JavaScript Mobile Apps Using Apache Cordova

Developing JavaScript
Mobile Apps Using
Apache Cordova
Hazem Saleh

About me
experience
More than ten years of experience in Java
enterprise and mobile solutions.
Apache Committer.
Author of four technical books.
DeveloperWorks Contributing author.
Technical Speaker (JavaOne, ApacheCon, Geecon …etc)
Advisory Software Engineer in IBM.

Agenda
Apache Cordova Introduction
Configurations
Cordova Command Line
Cordova APIs Overview
Memo Application Demo
Hello World Demo
jQuery Mobile Integration Tips

Platform
HTML CSS
JS

Device native functions examples:

Hybrid Application
(Cordova)
Native Application
Can be uploaded to App
Store
Yes yes
Technology HTML + CSS + JavaScript Native platform
Programming Language
Cross-mobiles support Yes No
Development Speed Faster Slower
Uses Device Native
Features
Yes yes
Hybrid vs Native Application

Cordova is supported on the following platforms:

Challenges of the current mobile apps development:
Many platforms and
devices.
Different skills needed.
Different problem types.
Huge Development and Testing Effort to
have a single application on these platforms.
For Android: Java skills needed.
For iOS: Objective-C (or SWIFT)
skills needed.
For Windows: C# skills needed.

Who can use Cordova?
If you are a web developer and wants to develop a mobile
application that can be deployed on the different app store
portals.
If you are a mobile native developer and wants to develop a
single application on the different mobile platforms without
having to re-implement the application code on every platform.

Configuration
1 2 3
Prerequisites:
Node JS.
Target SDK.
From command line:
> sudo npm install -g cordova
To know the
installed version of
Cordova:
> cordova -v
GIT

Cordova Command Line
To create an application:
> cordova create <<app_dir>> <<project_id>> <<app_title>>
To add a platform (from the
app folder):
> cordova platform add <<platform_name>>
To build Cordova project:
> cordova build
To deploy the app on
emulator:
> cordova emulate <<platform_name>>

Native device functions are represented as plugins that can be
added and removed using the command line.
Adding camera plugin
example:
> cordova plugin add https://git-wip-
us.apache.org/repos/asf/cordova-plugin-camera.git
Removing Camera plugin
example:
> cordova plugin rm org.apache.cordova.core.camera

Device
An object that holds information about the device
hardware and software.
Device information is mainly about:
 Device name.
 Device Platform.
 Device Platform version.
 Device model.
“deviceready” event is an indicator that Cordova finishes
loading and Cordova APIs are ready to be called.

Camera
An object that provides an access to the device camera.
It can be used for:
 Capturing a photo using the device’s Camera.
 Picking a photo from the device’s gallery.
navigator.camera.getPicture(onSuccess, onFail, { quality: 50,
destinationType: Camera.DestinationType.DATA_URL
});
function onSuccess(imageData) {
var image = document.getElementById('myImage');
image.src = "data:image/jpeg;base64," + imageData;
}
function onFail(message) {
alert('Failed because: ' + message);
}

Media
An object that allows recording and playing back audio
files on the device.
var my_media = new Media("someFile.mp3", onSuccess,
onError);
my_media.play();
function onSuccess() {
console.log("playAudio():Audio Success");
}
function onError(error) {
alert('code: ' + error.code + 'n' + 'message: ' +
error.message + 'n');
}

Notification
An object that displays visual, audible, and tactile
notification.
// Show a native looking alert
navigator.notification.alert(
'Cordova is great!', // message
'Cordova', // title
'Ok' // buttonName
);
// Beep four times
navigator.notification.beep(4);
// Vibrate for 3 seconds
navigator.notification.vibrate(3000);

Storage
Provides an access to the W3C Web Storage interface:
window.localStorage.setItem("key", "value");
var value = window.localStorage.getItem("key");
window.localStorage.removeItem("key");
window.localStorage.clear();
- Local Storage (window.localStorage).
- Session Storage (window.sessionStorage).

Storage
Provides an access to the device Web SQL Database
(Full featured database). Cordova supports IndexedDB
for WP8 and Blackberry 10.
function populateDB(tx) {
tx.executeSql('DROP TABLE IF EXISTS DEMO');
tx.executeSql('CREATE TABLE IF NOT EXISTS DEMO (id unique, data)');
tx.executeSql('INSERT INTO DEMO (id, data) VALUES (1, "First row")');
tx.executeSql('INSERT INTO DEMO (id, data) VALUES (2, "Second row")');
}
function errorCB(err) {
alert("Error processing SQL: " + err.code);
}
function successCB() {
alert("success!");
}
var db = window.openDatabase("Demos", "1.0", "Cordova Demo", 200000);
db.transaction(populateDB, errorCB, successCB);

Accelerometer (Capture device motion)
Compass (Get the device direction)
Connection (Get the device connection)
Contacts (Access to device contacts database).
File (Access to device File system based on W3C File API)
Globalization (Access to user locale information)
Events (Handle Apache Cordova life cycle events).
Geolocation (Know your mobile location. API is W3C based)
More APIs:

jQuery Mobile Integration
jQuery Mobile is:
One of the most popular User Interface framework for building Mobile
Web applications.
Uses HTML5 + CSS3 for layout pages with minimal scripting.
Compatible with most of the mobile and tablet browsers.

Cordova does not restrict using any specific JavaScript library but using
a JavaScript library will save you a lot of time creating your own
widgets from scratch.
jQuery Mobile is used in the demo application with Cordova to create
the Memo utility.
There are also many cool frameworks you can use in your Cordova
mobile apps such as:
Angular JS + lonic. Dojo mobile Sencha Touch.

Windows Phone 8 Issues:
Fixes:
Trimmed header title.
Footer is not aligned to bottom.
Set ui-header and ui-title classes’
overflow to visible.
Hide System Tray using app config
(shell:SystemTray.isVisible = “False”).

iOS 7 (and 8) Issues:
One of the possible
workarounds:
Collision between jQM header title
and iOS device status bar.
Hide the status bar by adding and
setting two properties in the app's
.plist file:
1. The Status bar is initially hidden
property set to the YES value.
2. The View controller-based status
bar appearance property set to the
NO value

In order to boost the performance of jQuery mobile with
Cordova, it is recommended to disable transition effects as
follows:
$.mobile.defaultDialogTransition = 'none’;
$.mobile.defaultPageTransition = 'none';

GitHub URL:
https://github.com/hazems/cordova-mega-app
MEMO APPLICATION

JavaScript Quiz
<script>
var number = 50;
var obj = {
number: 60,
getNum: function () {
var number = 70;
return this.number;
}
};
alert(obj.getNum());
alert(obj.getNum.call());
alert(obj.getNum.call({number:20}));
</script>

Questions
Twitter: @hazems
Blog: http://www.technicaladvices.com
Email: hazems@apache.org

[JavaLand 2015] Developing JavaScript Mobile Apps Using Apache Cordova

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