Android Dev

android.md

Android Development

High-level Overview

Components of an Android App

• Intents
  • Activity
  • Service
  • Content Provider
  • Broadcast Receiver
  • Manifest - an XML file that declares the components (above) and some properties o fthe app

Activity

• a single screen with a UI
• independent unit which can work together to form a cohesive whole
• can be invoked by other apps

Service

• app component that performs a usually long-running operation in the background, e.g., music or download service
• do not interact with user or provide UI

Content Provider

• provides a structure interface to a set of data
  • within an app
  • to share data with other apps (e.g., address book for telephone and messaging apps)

Broadcast Receiver

• can be registered to receive system or app events
• can get notified by Android system every time an event of the registered type occurs
• e.g., music app registers to listen for phone calls, lowers volume of audio when calls come in and it is notified by Android system

Intents

• an abstract description of an operation to be performed, w/2 parts:
  • action to be performed
  • data on which action operates
  • e.g., phone call: action: call placement, data: phone #
  • provide a way for devs to provide late binding between different apps, i.e., to connect apps that were not initially intended to be connected, i.e., allow for binding at run-time of otherwise completely decoupled apps

 

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Android Activity Lifecycle

Rendering Error Fix

Try: File -> Invalidate Caches/Restart

Setting up Virtual Device

Tools -> AVD Manager

+ Create Virtual Device

• If you get GPU or GL errors or things hang before starting up, try changing virtual device setting Graphics from automatic to software