iOS Backgrounding - SLC Cocoaheads

BackgroundingBursting Your Bubble on iOS

SorryDoing what you want in the backgroundis almost impossible

photo by protographer23

Get Your Notepads ReadySuspending vs. ResumingLocal NotificationsDoing Stuff in the Background

Exiting vs. ResumeSince iOS 4, you can keep your app“open” on exitBut it’s really just a “freeze” andresume - nothing happens while it’sin the background

Resume MeSet the ‘UIApplicationExitsOnSuspend’to ‘NO’ in your Info.plist

App Delegate Events App Initial Load -> Exit: applicationDidBecomeActive applicationWillResignActive applicationDidEnterBackground On Relaunch: applicationWillEnterForeground

Sounds PromisingapplicationDidEnterBackground soundspromising, but you can’t do anythinginside it that is long-running. Docs say you have 5 seconds You can’t get back to the UI

Terminate on ExitSet ‘UIApplicationExitsOnSuspend’ to‘YES’ in your Info.plist

App Delegate Events App Launch -> Exit: applicationDidBecomeActive applicationDidEnterBackground applicationWillTerminate

Kill MeIf the user does the jiggle and Red-Xes the app, no events are fired

Local NotificationsYou can schedule local notificationsto prompt the user at a future timeeven if your app isn’t runningUseful - but remember the user isn’trequired to open the app, and yournotification may never appear

Ok, NextSo you “can” do things in thebackground, but it’s limited to 3things: Get GPS updates Play Justin Bieber Do the VOIP

Set Your PlistDo do one of those 3 lovely things inthe background, set the‘UIBackgroundModes’ in yourInfo.plistValues are: location, audio, voip

LocationGet super duper real-time updates ormajor changes onlyUse CLLocationManager to do the magic

Playing AudioIt’s easy: start playing your tunesusing AV* framework.If something else starts playingmusic, you lose

VOIPSorry, no demo.But supposedly you can open a socketand keep it open.

Fighting the ManPeople have tried tricking the systemby playing an “empty” sound file.This works until some other app playssound.GPS Updates take up battery power, soyour users may hate you.

ConclusionRead more at: http://developer.apple.com/library/ios/ #documentation/iphone/conceptual/ iphoneosprogrammingguide/ BackgroundExecution/ BackgroundExecution.htmlSample Code: https://github.com/dnstevenson/BackgroundTestGood Luck!

Thanks!Find me on Twitter @dnstevensonBuy one of my apps at http://www.stevensonsoftware.comLeave me a 5-star review and I’ll beyour best friend

iOS Backgrounding - SLC Cocoaheads

by Dave Stevenson on Sep 07, 2011

Accessibility

Categories

Tags

Upload Details

Usage Rights

1 Embed 90

Statistics

iOS Backgrounding - SLC Cocoaheads — Presentation Transcript