Application fundamentals
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This document discusses the main components of Android apps: activities, services, broadcast receivers, content providers. It describes what each component is used for and its lifecycle. It also covers resources, packaging and installing apps, and the overall workflow for building an Android app from defining resources to running the app.
Application fundamentals
- 5. Apps are made from components Android instantiates and runs them as needed Each component has its own purpose and APIs
- 6. Primary class for user interaction Usually implements a single, focused task that the user can do
- 9. Runs in the background to perform long-running operations to support interaction with remote processes
- 13. Component that listens for and responds to events The subscriber in publish/subscribe pattern Events represented by the Intent class and then Broadcast
- 14. Component that listens for and responds to events The subscriber in publish/subscribe pattern Events represented by the Intent class and then Broadcast BroadcastReceiver receives and responds to broadcast event
- 18. Store & share data across applications Uses database-style interface Handles interprocess communication
- 23. User enters an address App displays a map of area around the address
- 25. See: http://developer.android.com/guide/! developing/building
- 26. 1. Define resources 2. Implement application classes 3. Package application 4. Install & run application
- 27. Resources are non-source code entities Many different resource types, such as Layout, Strings, Images, Menus, & animations Allows apps to be customized for different devices and users See: http://developer.android.com/guide/! topics/resources
- 28. Types: String, String Array, Plurals
- 29. Types: String, String Array, Plurals Typically stored in res/values/*.xml Specified in XML, e.g., <string name="hello">Hello World!</string> Can include formatting and styling
- 30. Accessed by other resources as: @string/string_name Accessed in Java as: R.string.string_name
- 31. MapLocation
- 33. If your default language is Italian, @string/location_string is “Digita l’indirizzo” Otherwise, “Enter Location”
- 36. UI layout specified in XML files Some tools allow visual layout XML files typically stored in res/layout/*.xml Accessed in Java as: R.layout. layout_name Accessed by other resources as: @layout/layout_name
- 37. Can specify different Layout files based on your device’s orientation, screen size, etc.
- 39. MapLocation
- 43. At compilation time, resources are used to generate the R.java class Java code uses the R class to access resources
- 45. MapLocation
- 46. Usually involves at least one Activity Activity initialization code usually in onCreate()
- 47. Typical onCreate() workflow Restore saved state Set content view Initialize UI elements Link UI elements to code actions
- 49. MapLocation
- 50. MapLocation
- 51. System packages application components & resources into a .apk file Developers specify required application information in a file called AndroidManifest.xml
- 52. Information includes: Application Name Components Other Required permissions Application features Minimum API level
- 54. MapLocation
- 55. From Eclipse run in the emulator or device From command line Enable USB Debugging on the device Settings > Applications > Development > USB debugging % adb install <path_to_apk>