Android Services CS 4720 Mobile Application Development Resource: - - PowerPoint PPT Presentation

CS 4720

Android Services

CS 4720 – Mobile Application Development Resource: developer.android.com

CS 4720

The Android Architecture

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CS 4720

The Service

• A Service is a process running the background
• It does not have a UI
• A Service can communicate with the user

through Toasts and the Status Bar

• Services can do basically anything in the

background:

– Download/Upload Data – Listen for data changes (location, etc.) or Intents – Log information

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CS 4720

Service Lifecycle

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CS 4720

Service Lifecycle

• A Service’s lifecycle is a bit different from an

Activity

– onCreate() – basically the same as Activity – onStartCommand() – gets the service going – onBind() – allows a Service to be a provider – onDestroy() – basically the same as Activity – stopSelf() – called by the Service to end it – startService() and stopService() – Intent calls to start and stop a Service

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CS 4720

Starting and Stopping

• Works almost exactly the same as starting an

Activity with an Intent (see code example)

• However, a Service will keep running after

Activities close

• You MUST manage your Services! Stopping

them is necessary to not take up extra resources

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CS 4720

Binding

• Consider a “normal” Service as doing a

background activity for a single Activity

• A Service that implements onBind() is one that

is exposing some functionality for other Activities to utilize

• onBind() is called by other Activities to access

the functionality

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CS 4720

In the Foreground

• Services can be set to run in the foreground
• Using startForeground() will start a Service that

the system knows it can’t just kill if necessary

• The Service should provide direct access to the

user for interaction, such as the status bar

• Example: a music player

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CS 4720

What to do with it?

• What can you do with a service?
• Example code time again!

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