Hands-on

Mobile App Development

 

with

It's Coding Time.

We're going to build a 'social weather tracking' app.

Let's begin by viewing a typical brief from a client.

Brief

I'd like a social weather tracking app, please.

(slightly less) Brief

I'd like an app which allows users to view and upload pictures of the weather, wherever they are.

The app should allow a user to use their smartphone to share a picture of the weather with a title and short description. 

The app should work on iPhone and Android devices.

User Stories

As a <type of user>, I want <some goal>
so that <some reason>.

A standard way of writing requirements from a user's point of view.

The starting point: user stories should then be split into a series of tasks.

User Stories

As a user I want to view other people's weather photos so that I know what the weather is like near me.

Examples for our app:

As a user I want to upload a new weather photo.

As a user I want to limit the amount of data used over my phone's data connection so that my bill is low.

Wireframes

A low fidelity example of how the app will function.

'A picture speaks a thousand words'

Includes key UI components for each screen.

Often static - sometimes dynamic.

Low fidelity on purpose: focus on functionality, not looks.

Wireframes

List of Posts

Post Detail

Add Post View

Section A

Setting up Project

 

Goals:

Scaffold new Ionic project

Understand project structure

Setup new project

$ ionic start climatic-app blank --type ionic1 --skip-link

$ cd climatic-app

$ ionic serve

You should now see a (very basic) Ionic app running in the browser.

We'll be building most of the app using the browser before deploying to our phones.

Directory Structure

Section B

List View

 

Goals:

Create a List View

List View

Used to render lists of data.

Task

Render controller items in the list.

Hint: use `ng-controller` and `ng-repeat`.

Task

Render thumbnail images in list.

Hint: use the list HTML markup from the Ionic Docs.

Hint: use `ng-src` in the img tags.

Section C

Fetching Data from Server

 

Goals:

Fetch list data from server

Promises

Represents the result of an asynchronous operation.

Can be in one of three states:

Pending       Resolved       Rejected

 

Promises often used for async operations such as fetching data from a server.

Promises: by example (1)

Request file from server

Server receives request, sends file

File received

Promise State

Operations

pending

pending

resolved

Promises: by example (2)

Request file from server

Server can't find requested file

Error received

Promise State

Operations

pending

pending

rejected

Promises: by example (3)

We use then and catch to receive the data returned from the async operation.

var promise = getDataFromServer();

function onResolved(data) {
  // Do something with data
}
promise.then(onResolved);

function onRejected(error) {
  // Handle error
}
promise.catch(onRejected);

Angular Factories

Singleton objects

Often used to fetch data from server

Promises often returned for async operations such as data fetching

Task

Return posts from posts.factory.js

Hint: use $q to return a promise

Fetching Data from Server

Our app will be syncing data from a backend server

The server is implemented using Parse

We'll be using the Parse library in app to communicate with the backend

Installing Parse library

Third party libraries are installed using bower

To install the Parse library, run:

$ bower install parse --save-dev

We can then import and use the library in our app.

Task

Return posts from backend server

Section D

Infinite Scrolling

Goals:

Use infinite scrolling to fetch all data from server

Infinite Scrolling

Automatically load next content when user scrolls to the bottom of the list

Ionic directive ion-infinite-scroll makes it easy to add into our app

Task

Add infinite scrolling to app

Hint: use `loadNext` method in controller to load more data from the infinite scroll directive

Hint: use `hasMorePosts` flag in controller to disable infinite scroll if there are no more posts to fetch

Section E

Loading Indicator

Goals:

Show loading indicator while fetching data

Loading Indicator

Show a progress indicator while data is loading

Use $ionicLoading service to show and hide Ionic's loading indicator

Task

Show loading indicator while data is being fetched from server

Hint: show indicator before fetching posts in controller, then hide indicator afterwards

Task

Show same loading spinner for first load and infinite scroller

Hint: use the 'lines' spinner. See docs at

http://ionicframework.com/docs/v1/api/directive/ionSpinner/

Section F

Custom Styles

Goals:

Update app with custom styles

Custom Styles

Ionic uses the SASS preprocessor to compile its default styles.

You can override these styles by setting SASS variables.

Change colors, fonts, text sizes, paddings and more.

Task

Change colour scheme for app:

Set 'positive' to #68AA63

Set 'calm' to #D7A872

Set 'assertive' to #D03C39

Hint: modify the file in the 'scss' folder to
update the styles.

Section G

Running and Debugging

 

Goals:

Run Ionic Lab feature to show iOS vs Android layout

Debug app in browser

Debug app on device

$ ionic serve -l

Preview app in iOS and Android modes.

$ ionic cordova run android

Run app on Android device. 

$ ionic emulate ios

Run app in iOS simulator.

$ ionic serve -w chromium-browser

Tip: ionic serve opens your default browser.
Use the -w flag to open in a different browser.

Section H

Routing

Goals:

Add URL routing to app

Routing

All but the simplest app uses more than one screen.

The classic example is the 'list-detail' view:

Routing

Ionic mimics a native app:

Detail view is 'pushed' over list view

Back button appears on detail view

Tapping Back 'pops' detail view, returns to list

Routing

To support routing, we must make changes to the index.html page.

<body ng-app="climatic">
  <ion-nav-bar class="bar-positive">
    <ion-nav-back-button></ion-nav-back-button>
  </ion-nav-bar>
  <ion-nav-view></ion-nav-view>
</body>

Our content will be automatically rendered in the <ion-nav-view> element.

Routing

The contents of <ion-nav-view> are populated by the router:

$stateProvider.state('feed', {
  url: '/posts',
  templateUrl: 'tmpl/posts/feed.html',
  controller: 'FeedController',
  controllerAs: '$ctrl'
});

The page content now lives in a separate template file

Task

Restore 'Climatic' title in navbar

Hint:

Section I

Detail View

Goals:

Tap list item, to view details of the post

Routing

To route from list to detail view, we use a regular HTML <a> tag, with a custom attribute `ui-sref`

<ul class="list">
  <li ng-repeat="item in $ctrl.posts">
    <a ui-sref="post({id: item.objectId})">
      <h2>{{:: item.title }}</h2>
    </a>
  </li>
</ul>

ui-sref calls `post` function, which matches router config to change the page

Task

Add detail view template and controller to router config

Routing

Data passed into `ui-sref` is accessible via the `$stateParams` service

angular
  .module('climatic')
  .controller('PostController', PostController);

function PostController($stateParams) {
  var id = $stateParams.id;
  
  // id is the value passed in by `ui-sref`
  // Do something with it...
}

Task

Implement `getPostById` in post factory to return correct item

Hint: use a loop to fetch the correct post from the `posts` array, according to the passed ID

Section J

Platform-Specific UI

Goals:

Tweak UI for device platform
(iOS vs Android)

Platform Specific UI

Native iOS and Android UIs are different:

Ionic will automatically render some components differently for each platform.

There are also ways to manually customise the UI depending on the runtime platform.

Render right chevron arrows
on iOS but not Android

Task

Resources:

Hint: use Ionic Labs mode to see both platforms in browser

Section K

'Add Post' Modal

Goals:

Show a pop-up modal with a form to create a new post

Modal

Another way to display a new screen is via a 'modal'

A modal is a full-screen pop-up window

Modal

Ionic has a built-in service, $ionicModal

Modal is shown and hidden from JavaScript, typically via `ng-click`

Modal content rendered from template file

Modal

Modal is revealed from bottom of screen

Consumes entire screen, including header bar

Modified header bar includes controls to dismiss modal

Navbar Buttons

Show buttons in navbar with <ion-nav-buttons> directive

<ion-view>
  <ion-nav-title>Climatic</ion-nav-title>
  <ion-nav-buttons side="secondary">
    <button class="button"></button>
  </ion-nav-buttons>
  <ion-content>
  </ion-content>
</ion-view>

Task

Reveal modal when header bar + button is tapped

Hint: modal can be revealed by calling function in FeedController

Task

Hide modal when header bar tick or cross is tapped

Hint: modal HTML has access to everything in FeedController

Section L

'Add Post' Form

Goals:

Add form elements to Add Post modal

Ionic Forms

Ionic ships with styles for many different form elements.

Task

Add following form elements to modal:

'Title' (text)

'Description' (textarea)

Task

Bind input and textarea values to controller 'addPostData' object

Hint: use 'ng-model' directive

Elastic textareas

Ionic does not provide this out-of-the-box, so we must use a third party library:

Native apps: multi-line text inputs automatically grow/shrink when text is typed.

$ bower install angular-elastic --save-dev

Task

Use angular-elastic plugin to auto grow and shrink textarea when content changes

Hint: read docs at

Use the 'attribute' method

Section M

Take Picture

Goals:

Take picture from phone camera and include in form data

A container to run HTML, CSS and JavaScript code as a native app.

Loads the code in an embedded Webview, without the standard browser controls,
so the app feels like a native app.

Provides plugins to access native APIs via JS, such as the camera, filesystem and push notifications.

We'll be using the Camera plugin to take pictures from our app.

$ cordova plugin add cordova-plugin-camera

Angular wrapper for Cordova plugins.

Built by Ionic team, for Ionic!

$ bower install ngCordova --save-dev

Install with Bower:

Task

Hook up button to take picture

Show resulting picture in app

Hint: call `$ctrl.addPicture()` when button is tapped

Hint: use `ng-if` to conditionally render button or image

Task

Hook up button to take picture

Show resulting picture in app

Hint: call `takePicture()` when button is tapped

Hint: use `ng-if` to conditionally render button or image

$ionicPopup

Ask the user for response to continue

Display small 'pop-up' box in centre of app

Task

Show popup if there was an error when taking the picture

Hint: use the `$ionicPopup` service

Hint: add code to the `FeedController`

Task

Render Retake Picture' and 'Delete Picture' buttons once picture has been taken

'Retake Picture': replace existing picture

'Remove Picture': remove existing picture

Hint: use 'assertive' colour and different icon for 'Remove Picture' button

Section N

Form Validation

Goals:

Ensure form data is valid before saving to server

Task

Disable 'Save' button if the title, description or picture fields are empty

Hint: use the `ng-disabled` attribute on the save button

Hint: have `ng-disabled` call a function in the FeedController to check if the fields are empty or not

Section O

Saving Form Data

Goals:

Save post to server

We'll be using Parse again to save the data to the server.

Task

Save data to the server, and close the modal when it has saved

Hint: we need to implement the `savePost` function in the FeedController

Hint: call the `savePost` function inside the PostsFactory to save the data. This returns a promise, which is resolved when the data is saved.

Task

Refresh the feed page when the data has been saved correctly

Hint: find the existing code in FeedController which loads the feed when the app starts, and reuse it for this task

Task

Show a loading spinner while the data is being saved

Hint: re-use the same loading spinner which is shown when the app first loads the feed data

Section P

Refreshing Data

Goals:

Implement pull-to-refresh on list

Pull to Refresh

Drag list downwards to refresh

Ionic includes built-in directive for pull-to-refresh:

Task

Add pull-to-refresh to list view

Hint: use `ion-refresher` directive

Hint: don't forget to call `$scope.$broadcast` once refresh has completed

Section Q

Polishing

Goals:

Add icon & splashscreen

Change headerbar colour

From a single image, Ionic can generate app icons and splashscreen images in each different format, for each platform.

Icons and Splashscreen

Each platform requires a large number of different-sized icons and splashscreen images to support all different devices.

If you didn't sign up earlier, do so now with:

Icons and Splashscreen

You need to have an Ionic account to generate resources.

$ ionic signup

Icons and Splashscreen

Generate pngs from Ionic icon / splashscreen photoshop files

Put png files in resources/ folder

Run command to generate all icons and splashscreens:

$ ionic cordova resources

Task

Generate icons and splashscreen from provided files

Status Bar: iOS

On iOS, the status bar is transparent: your app's headerbar will appear beneath the statusbar text.

Status Bar: iOS

Control the status bar text colour with the Cordova StatusBar plugin:

Modify the following lines in app.js to change the status bar text to white:

if(window.StatusBar) {
  StatusBar.styleLightContent();
}

Status Bar: Android

Material Design guidelines: 

use a darkened tint of your main headerbar colour for status bar

Status Bar: Android

Set base (500) colour using colour picker

Choose a darker tint for the headerbar. Suggestion: pick 700 colour to start with.

Status Bar: Android

Use the $ionicPlatform factory to to change the status bar colour for Android only

if(window.StatusBar) {
  if($ionicPlatform.is('ios')) {
    StatusBar.styleLightContent();
  } else if ($ionicPlatform.is('android')) {
    StatusBar.backgroundColorByHexString('#559951');
  }
}

Task

Change statusbar colours for iOS and Android

Recents View Bar: Android

The Recents View is shown when the Android 'Recents' button is pressed.

We should set the headerbar colour in this view to match our primary theme colour.

Task

Change Recent Task Bar colour to match statusbar

Hint: use Cordova plugin:

Ionic Course, Part 2: Build the App

By Tom Spencer

Ionic Course, Part 2: Build the App

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