For Best User Experience & UI

　　　These classes focus on the best Android user experience for your app. In some cases, the success of your app on Android is heavily affected by whether your app conforms to the user's expectations for UI and navigation on an Android device. Follow these recommendations to ensure that your app looks and behaves in a way that satisfies Android users.

1. Designing Effective Navigation

   How to plan your app's screen hierarchy and forms of navigation so users can effectively and intuitively traverse your app content using various navigation patterns.

   1. Planning Screens and Their Relationships
   2. Planning for Multiple Touchscreen Sizes
   3. Providing Descendant and Lateral Navigation
   4. Providing Ancestral and Temporal Navigation
   5. Putting it All Together: Wireframing the Example App

2. Implementing Effective Navigation

   How to implement various navigation patterns such as swipe views and up navigation.

   1. Implementing Lateral Navigation
   2. Implementing Ancestral Navigation
   3. Implementing Temporal Navigation
   4. Implementing Descendant Navigation

3. Notifying the User

   How to display messages called notifications outside of your application's UI.

   1. Building a Notification
   2. Preserving Navigation when Starting an Activity
   3. Updating Notifications
   4. Using Big View Styles
   5. Displaying Progress in a Notification

4. Adding Search Functionality

   How to properly add a search interface to your app and create a searchable database.

   1. Setting up the Search Interface
   2. Storing and Searching for Data
   3. Remaining Backward Compatible

5. Designing for Multiple Screens

   How to build a user interface that's flexible enough to fit perfectly on any screen and how to create different interaction patterns that are optimized for different screen sizes.

   1. Supporting Different Screen Sizes
   2. Supporting Different Screen Densities
   3. Implementing Adaptive UI Flows

6. Designing for TV

   How to optimize your app's user interface and user input for the "ten foot experience" of a TV screen.

   1. Optimizing Layouts for TV
   2. Optimizing Navigation for TV
   3. Handling Features Not Supported on TV

7. Creating Custom Views

   How to build custom UI widgets that are interactive and smooth.

   1. Creating a Custom View Class
   2. Implementing Custom Drawing
   3. Making the View Interactive
   4. Optimizing the View

8. Creating Backward-Compatible UIs

   How to use UI components and other APIs from the more recent versions of Android while remaining compatible with older versions of the platform.

   1. Abstracting the New APIs
   2. Proxying to the New APIs
   3. Creating an Implementation with Older APIs
   4. Using the Version-Aware Component

9. Implementing Accessibility

   How to make your app accessible to users with vision impairment or other physical disabilities.

   1. Developing Accessible Applications
   2. Developing Accessibility Services

Reprinted From:http://developer.android.com/training/best-ux.html