Android Overview and Versions

Android Overview

• Android is an open-source operating system developed by Google
• It is designed for mobile devices, including smartphones and tablets.
• Android boasts a vast developer community and significant marketing reach.
• It enables inter-app integration, reducing development costs and increasing success rates.
• Android offers a rich development environment with extensive tools and libraries.

Android Versions

• Alpha (1.0): Introduced Google Maps, Camera, and basic system features.
• Beta (1.1): Added Gmail, Contacts, Google Synchronization, and a web browser.
• CupCake (1.5): Redesigned UI, improved web browser functionality, and introduced video uploading.
• Donut (1.6): Provided support for larger screens, enhanced camera and gallery features, and improved system app performance.
• Éclair (2.0 & 2.1): Introduced Live Wallpapers, enhanced Bluetooth capabilities, and improved Google Maps.
• Froyo (2.2): Added animated GIFs, WiFi hotspot functionality, and provided speed enhancements.
• GingerBread (2.3 & 2.4): Improved copy-paste functionality, enhanced keyboard usability, and featured updated UI design.
• Honeycomb (3.0, 3.1, & 3.2): Enhanced Gmail app, featured a 3D UI, and introduced Adobe Flash support for browsers.
• Ice Cream Sandwich (4.0): Improved text input and spell check, introduced Face Unlock, and enhanced video recording features.
• JellyBean (4.1, 4.2, & 4.3): Introduced Google Now, enhanced voice search functionality, and improved camera applications.
• KitKat (4.4): Introduced screen recording, "OK Google" voice activation, improved GPS support, and offline music playback.
• Lollipop (5.0 & 5.1): Introduced Android Runtime (ART), enhanced battery saving features, and improved user interface with Material Design.
• Marshmallow (6.0): Introduced fingerprint authentication, USB Type-C compatibility, and introduced Doze mode for battery saving.
• Nougat (7.0): Introduced native split-screen multitasking, data saver features, and improved storage manager.
• Oreo (8.0): Introduced picture-in-picture (PIP) support, multi-display support, and improved notification system.
• Pie (9.0): Introduced a dedicated screenshot button, lockdown mode for biometric security, and adaptive battery and brightness features.
• Queen Cake or Quince Tart (10): Introduced dynamic depth format for photos, system-wide dark mode, and sharing shortcuts.
• Red Velvet Cake (11): Introduced native screen recording, notification muting during video playback, auto-revoke app permissions, and notification history.
• Snow Cone (12): Introduced scrolling screenshots, enhanced app search, simplified WiFi sharing, and a one-handed mode.
• Tiramisu (13): Introduced enhanced security features, a new reading mode, digital car keys support, and additional Material You theme options.
• Upside Down Cake (14): Introduced smarter scaling, notification flashes, restrictions on photo/video access, and predictive back gestures.
• Vanilla Ice Cream (15): As of the most recent information, specific features have not been fully detailed.

Android Architecture Hierarchy

• Applications: The uppermost layer of the Android architecture.
• Application Framework: Provides core classes for application development and abstraction for hardware access.
• Android Runtime: Includes core libraries and the Dalvik virtual machine, forming the basis for application framework execution.
  • It relies on the Linux kernel for threading and memory management.
• Platform Libraries: Provides support for Android development through C/C++ and Java-based libraries.
• Linux Kernel: The foundation layer of the Android architecture, responsible for device drivers, memory management, and hardware abstraction.

Android Components

• Activities: Represents a single screen of the user interface.
• Services: Operates in the background, performing long-running tasks without a user interface.
• Content Providers: Manages and shares app data with other apps on the device.
• Broadcast Receivers: Responds to system-wide broadcasts, such as battery level changes or network connectivity updates.
• Intents: A messaging system allowing different components to communicate with each other.

Android Resources

• anim: XML files for property and tween animations
• color: XML files that define state lists of colors, accessible through the R.color class.
• drawable: Image and XML files for bitmaps, state lists, shapes, and animation drawables, accessible through R.drawable.
• layout: XML files that define the layout structure of the UI, accessible through R.layout.
• menu: XML files that define app menus, accessible through R.menu.
• raw: Arbitrary raw files accessible through Resources.openRawResource().
• values: XML files containing simple values such as strings and colors.
• xml: Arbitrary XML files accessible at runtime through Resources.getXML().
• font: Font files (TTF, OTF, etc.) and XML files that define fonts, accessible as resources.

How to Access Resources

• In Code: Access resources through the Resources object. For example, you can access an image through myimage = R.drawable.myimage.
• In XML: Use @name/value syntax, such as android:background="@drawable/myimage".

Activity Life Cycle

• onCreate(): Called when the activity is first created.
• onStart(): Called when the activity becomes visible to the user.
• onResume(): Called when the user interacts with the activity (becomes active).
• onPause(): Called when the activity is no longer the active one (temporarily in the background).
• onStop(): Called when the activity is no longer visible to the user.
• onRestart(): Called when the activity is reopened from a stopped state.
• onDestroy(): Called before the activity is destroyed permanently.

Layouts and Views

• Layouts: Define the structure of the user interface.
  • Common layout types include LinearLayout, RelativeLayout, and FrameLayout.
• Views: Visual components that users interact with.
  • Attributes include:
    • android:id: A unique identifier for the view.
    • android:layout_height: The height of the view.
    • android:layout_width: The width of the view.
• ViewGroup: A container that holds other views.
  • Examples include LinearLayout, RelativeLayout, and FrameLayout.
• Views vs. ViewGroups:
  • Views directly draw elements that users see, while ViewGroups act as containers for other views.
  • ViewGroups do not always accept nested views.

This quiz covers the essentials of the Android operating system, including its features and the evolution of its versions from Alpha to Froyo. Explore how Android has become a significant player in the mobile device market and the tools available for developers.