Android Jam - Services & Notifications - Udacity Lesson 6

Android ManchesterWeek 8 - Services & Notifications

Overview

● Retro○ Lesson 6 Services & Notifications

● Looking Forward○ The Final Project

● Stickers● Next retro 31st March (2 weeks!)● Next Tues 7-8pm SpacePortX

Energizer

Stand up and introduce yourself to somebody around you, you don’t know

Prime Directive

‘Regardless of where we are up to, we understand and truly believe that everyone did the best job he or she could, given his or her skills and abilities, the personal time available, and the situation at hand.’

Difficulty Check● Who completed the class?

● How long did it take?

● Hands up 1-10 difficulty of the lesson

● Any specific areas of the lesson that require particular focus?

Retro lesson 6 services & notifications

What we learnt last week● Services● Application priority● Alarms● Transferring data efficiently● SyncAdapters● Notifications

Services● Execute long running tasks that shouldn’t be interrupted● Have a lifecycle but no user interface● Declared in the AndroidManifest

Services● Run on the main thread - which means…..?

○ AsyncTasks, SyncAdapter, IntentService etc.● Typically override onStartCommand● No state methods such as onResume, onPause etc

Service Extras● startForeground(Notification notification);

○ increases priority○ shouldn’t be killed to clear resources

● IntentService (subclass) provides onHandleIntent which runs off the main thread○ Executes Intents sequentially○ Good for downloading

App Priority

● Apps running in the background have a responsibility to be good citizens!

● Async Task can be used to download files/play music but risk being deleted when the app is in the background

● Services allow us to deal with these use cases

App Priority

App Priority - the 3 laws

Test...

● Consider effect on user experience● Consider component - is it an

Activity or Service?● User interaction● And is it background/foreground?

3 Laws

1. Android will ensure a smooth UX2. Android will keep all activities and

services running unless they violate the 1st law

3. Android will keep background apps running unless they violate 1st or 2nd law

Efficiency

Clue: We’re aiming for less data, less often

Battery Drain

The cell radio

Efficiency is driven by hardware considerations

The cell radio analysed

V

blue - active data transfersred - radio in full poweryellow - lower power modeblack - idle

Efficiency

Interlude - making good apps great

Further WatchingGoogle I/O 2013 - Android Protips 3: Making Apps Work Like Magic

https://www.youtube.com/watch?v=GcNNx2zdXN4

Google I/O 2012 - Android Protips 2:Making Good Apps Great

https://www.youtube.com/watch?v=PwC1OlJo5VM

Google I/O 2011: Android Protips: Advanced Topics for Expert Android App Developers

https://www.youtube.com/watch?v=twmuBbC_oB8

SyncAdapter

● Designed to sync local data with web efficiently● OS Batches requests with other apps to save battery.● Try not to run when radio is idle● Auto retry requests ● onPerformSync

Notifications

Notifications

● So far, all solutions of retrieving data/sync go Device -> Server (Poll)

● Notifications are Server -> Device (Push)- ○ can include payload in json format or request update

■ NB: Requesting too many updates concurrently can cause server traffic

○ More efficient than polling

What went well

What went well

● Efficient data transfer very useful● SyncAdapters - many applications can make use of them● The 3 laws for application priority - great way to

remember● Understanding the state radio helps understand why

little data transfers are actually worse!

What didn’t go so well

What didn’t go so well

● Less detail in this class● There is a lot to learn / know to get efficient data

synchronised applications● Copy n Paste for the sync adapter● Didn’t delete the old weather data until this

lesson!● “comment out” refresh button … but woohoo

SyncAdapter

Q&A

Next - Android JamProject Retro

Next Lesson - Project

Learning Objectives:- Final Project

Final ProjectYour Project must:

Import and build on the latest version of Android Studio Be entirely self-contained on an Android device (No external devices/bluetooth peripherals). Include a problem description of the problem your app solves. Include mocks for all user-facing screens. Include at least one alternate mock for tablet / large screens. Implement all mockups, including your tablet layout. Have at least two distinct Views (ex. a list view and a detail view). Work properly with the app lifecycle (i.e. resume state on orientation change). Use permissions responsibly. Use Intents to move between activities inside your app or to an outside app. Create and use your own ContentProvider Use Loaders to move your data to your views. If the application pulls or sends data to/from a web service or API, it handles this network activity properly

(i.e on the correct thread, does not abuse network resources) Include only safe-for-work content in your app

Final Project ExtrasFor extra Udacious-ness, include at least two of the following (optional):

Receive Broadcast events and do something meaningful. Create and use a custom View. Implement a ShareActionProvider, sharing rich content such as a picture or link. Use Notifications.

Final Project Ideas● Food ordering app● Teleprompter app ● Local news app● App for your company, university or local club● Education app● Public transit schedule● Reddit Reading List● Github OSS project tracker

● YouTube API● Twitter API● Weather API● www.programmableweb.com/apis/directory

Final Project Paul

Final Project Zain

Final Project Checklist

See you next but one week..

- Time: Tuesday 31st March 7pm - Place: SpacePort- Things needed: You + Questions +

Feedback- Can contact us if issues:

@blundell_apps / @android_mcr

Go forth & discuss do