Android Manchester

Week 4 - New Activities and Intents

Overview

● Retro

o Lesson 3 activities & intents

● Looking forward

o Lesson 4 lifecycles & databases

● Stickers + Booklets

● Next Tue 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 weeks lesson

● Any specific areas of the lesson that require particular

focus?

Retro activities & intents

What we learnt last week

● Toast UI feedback

● Creating the detail activity

● Navigation with Intents

● Settings with Preference Activity

● Remembering location with Shared Preferences

● ShareActionProvider

Lesson 3 - Detail Activity

Lesson 3 - Up vs Back

Up is always inside of the app, Back can take you out the app

Lesson 3 - Toast● Toast.makeText(activity, “Oh hai”, Toast.LENGTH_SHORT);

● Popup that displays a message for a few seconds before fading out

● Useful for debugging to give visual feedback without changing app UI

● Always remember to use the .show() method

● Toast is still an Android View so needs to be controlled from the Main

Thread

● You can customise a toast and use your own layout

● Whenever you want your app components to talk to each other or talk to the system you use an

Intent to specify the destination

● Intent is like an envelope

o Address of who to talk to

o Space to attach data

● Explicit Intent

o Intent with class name DetailActivity.class

● Implicit Intent

o Intent with data around an action to perform http://google.com

● Intents can cross the application (process) boundary

Lesson 3 - Intents

Lesson 3 - Settings Activity

Lesson 3 - Settings

http://developer.android.com/design/patterns/settings.html

Lesson 3 - PreferenceActivity

● Hierarchy of preferences

● UI is done for you

o checkbox, list, edittext, switch preferences

● Custom Preferences

● Preference XML file defining layout

● Manually monitor for preference changes to update UI

● Gingerbread does not have (easily) nested preferences

● Saves into Default SharedPreferences file

● Save Java primitive

Lesson 3 - SharedPreferences

● Key Value pairs

● PreferenceManager.getDefaultSharedPreferences()

● Context.getSharedPreferences()

● SharedPreferences.Editor

● MODE_PRIVATE , MODE_WORLD_READABLE / WRITEABLE

○ ContentProvider, Service, Broadcast

● commit() vs apply()

○ apply added in SDK 9 (2.3 Gingerbread)

Lesson 3 - ShareActionProvider

● Share Intent

● Add ShareActionProvider in XML menu

● Add Intent to ShareActionProvider

● Photos, apps, videos, general links

● No need to know what apps are available

● 4.0 and above (plus support library)

● important to jump out of task

o FLAG_ACTIVITY_CLEAR_WHEN_RESET

Lesson 3 - Broadcasting

sendBroadcast > > any app that is listening

Lesson 3 - BroadcastReceiver

● Extend BroadcastReceiver

● Register programmatically

○ remember to unregister!

● Register via AndroidManifest

● IntentFilter to select messages to

listen to

● 10 seconds to react

○ finish your work

○ start another component

What went well

What went well

- Seeing the wire frames and talking UX

- Breakpoints

- ShareActionProvider is so easy & bonus

functionality

What didn’t go so well

What didn’t go so well

- PreferenceActivity changes monitoring

- Writing implicit intent to start map activity ( a

lot of googling )- https://developer.android.com/guide/components/int

ents-common.html#Maps

- Add namespace manually for support library

widget xml (ShareActionProvider)

Q & A

Lesson - 3 - Activities and Intents

Next Week - Android JamActivity Lifecycle & Data

Next Lesson - Activity Lifecycle & Data

Learning Objectives:- Activity lifecycle

- Active and visible lifetime.

- Saving Activity State

- Databases

- ContentProviders basics.

See you next week..

- Time: Tuesday 7pm

- Place: SpacePort

- Things needed: You + Questions +

Feedback

- Can contact us if issues:

@blundell_apps / @android_mcr

Go forth and discuss