Create your first app using Apache Cordova
Apache Cordova is an open-source mobile development framework. It allows you to use standard web technologies — HTML5, CSS3, and JavaScript for cross-platform development. Applications execute within wrappers targeted to each platform and rely on standards-compliant API bindings to access each device’s capabilities such as sensors, data, network status, etc. To know more about Apache Cordova, please check out the documentation.
Here, we will have a quick walkthrough of steps and challenges faced in the installation, first app creation, and building of it using Apache Cordova.
The majority of the content is based on the documentation and added the notes extra based on my experience also here along with that.
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Installing the Cordova CLI
on OS X and Linux:
$ sudo npm install -g cordova
on Windows:
C:\>npm install -g cordova
Create the App
Go to the directory where you maintain your source code, and create a cordova project:
$ cordova create hello com.example.hello HelloWorld
This creates the required directory structure for your cordova app. By default, the cordova create script generates a skeletal web-based application whose home page is the project’s www/index.html file.
Below help content comes up on running cordova command.
Synopsiscordova command [options]Global Commandscreate ……………………….. Create a projecthelp …………………………. Get help for a commandtelemetry …………………….. Turn telemetry collection on or offconfig ……………………….. Set, get, delete, edit, and list global cordova optionsProject Commandsinfo …………………………. Generate project informationrequirements ………………….. Checks and print out all the requirementsfor platforms specifiedplatform ……………………… Manage project platformsplugin ……………………….. Manage project pluginsprepare ………………………. Copy files into platform(s) for buildingcompile ………………………. Build platform(s)clean ………………………… Cleanup project from build artifactsrun ………………………….. Run project(including prepare && compile)serve ………………………… Run project with a local webserver(including prepare)Learn more about command options using ‘cordova help <command>’Aliasesbuild -> cordova prepare && cordova compileemulate -> cordova run — emulatorOptions-v, — version …………………. prints out this utility’s version-d, — verbose …………………. debug mode produces verbose log output for all activity, — no-update-notifier …………… disables check for CLI updates — nohooks …………………….. suppress executing hooks(taking RegExp hook patterns as parameters)Examplescordova create myApp org.apache.cordova.myApp myAppcordova plugin add cordova-plugin-cameracordova platform add androidcordova plugin add cordova-plugin-camera — nosavecordova platform add android — nosavecordova requirements androidcordova build android — verbosecordova run androidcordova build android — release — — keystore=”..\android.keystore” — storePassword=android — alias=mykeycordova config ls
Add Platform
All subsequent commands need to be run within the project’s directory, or any subdirectories:
$ cd hello
Add the platforms that you want to target your app. We will add the ‘ios’ and ‘android’ platform and ensure they get saved to config.xml and package.json:
$ cordova platform add ios
$ cordova platform add android
To check your current set of platforms:
$ cordova platform ls
Install pre-requisites for building
To build and run apps, you need to install SDKs for each platform you wish to target. Alternatively, if you are using browser for development you can use browser platform which does not require any platform SDKs.
To check if you satisfy requirements for building the platform:
$ cordova requirements
This will give a Gradle related error if in case Gradle is not installed or it is not detected by Cordova.
Cordova uses Gradle to build. So install Gradle by following the manual installation steps for Windows. Best way to get Gradle in Windows is to install Android Studio as it comes with Gradle.
Build the App
By default, cordova create script generates a skeletal web-based application whose start page is the project’s www/index.html file. Any initialization should be specified as part of the deviceready event handler defined in www/js/index.js.
Run the following command to build the project for all platforms:
$ cordova build
You can optionally limit the scope of each build to specific platforms — ‘ios’ in this case:
$ cordova build ios
Test the App
SDKs for mobile platforms often come bundled with emulators that execute a device image, so that you can launch the app from the home screen and see how it interacts with many platform features. Run a command such as the following to rebuild the app and view it within a specific platform’s emulator:
$ cordova emulate android
Following up with the cordova emulate command refreshes the emulator image to display the latest application, which is now available for launch from the home screen:
Alternately, you can plug the handset into your computer and test the app directly:
$ cordova run android
Before running this command, you need to set up the device for testing, following procedures that vary for each platform.
Add Plugins
You can modify the default generated app to take advantage of standard web technologies, but for the app to access device-level features, you need to add plugins.
A plugin exposes a Javascript API for native SDK functionality. Plugins are typically hosted on npm and you can search for them on the plugin search page. Some key APIs are provided by the Apache Cordova open source project and these are referred to as Core Plugin APIs. You can also use the CLI to launch the search page:
$ cordova plugin search camera
To add and save the camera plugin to package.json, we will specify the npm package name for the camera plugin:
$ cordova plugin add cordova-plugin-camera
Fetching plugin “cordova-plugin-camera@~2.1.0” via npm
Installing “cordova-plugin-camera” for android
Installing “cordova-plugin-camera” for ios
Plugins can also be added using a directory or a git repo.
Use plugin ls (or plugin list, or plugin by itself) to view currently installed plugins. Each displays by its identifier:
$ cordova plugin ls
cordova-plugin-camera 2.1.0 “Camera”
cordova-plugin-whitelist 1.2.1 “Whitelist”
Using merges to Customize Each Platform
While Cordova allows you to easily deploy an app for many different platforms, sometimes you need to add customizations. In that case, you don’t want to modify the source files in various www directories within the top-level platforms directory, because they’re regularly replaced with the top-level www directory’s cross-platform source.
Instead, the top-level merges directory offers a place to specify assets to deploy on specific platforms. Each platform-specific subdirectory within merges mirrors the directory structure of the www source tree, allowing you to override or add files as needed. For example, here is how you might use merges to boost the default font size for Android devices:
· Edit the www/index.html file, adding a link to an additional CSS file, overrides.css in this case:
<link rel=”stylesheet” type=”text/css” href=”css/overrides.css” />
· Optionally create an empty www/css/overrides.css file, which would apply for all non-Android builds, preventing a missing-file error.
· Create a css subdirectory within merges/android, then add a corresponding overrides.css file. Specify CSS that overrides the 12-point default font size specified within www/css/index.css, for example:
body { font-size:14px; }
When you rebuild the project, the Android version features the custom font size, while others remain unchanged.
Updating Cordova and Your Project
After installing the cordova utility, you can always update it to the latest version by running the following command:
$ sudo npm update -g cordova
Use this syntax to install a specific version:
$ sudo npm install -g cordova@3.1.0–0.2.0
Run cordova -v to see which version is currently running. To find the latest released cordova version, you can run:
$ npm info cordova version
To update platform that you’re targeting:
$ cordova platform update android — save
$ cordova platform update ios — save
…etc.