Android Tutorial Lesson 4 - Arena

How to select more than one option from list in android
xml file?
Give an example.
Specify android id, layout height and width as depicted in
the following example.
What languages does Android support for application
development?
Android applications are written using the Java
programming language.
Describe Android Application Architecture.
Android Application Architecture has the following
components:
• Services – like Network Operation
• Intent - To perform inter-communication between
activities or services
• Resource Externalization- such as strings and graphics
• Notification signaling users - light, sound, icon,
notification, dialog etc.
• Content Providers - They share data between applications
Common Tricky questions
Remember that the GUI layer doesn't request data
directly from the web; data is always loaded from a local
database.
The service layer periodically updates the local
database.
What is the risk in blocking the Main thread when
performing a lengthy operation such as web access or
heavy computation? Application_Not_Responding
exception will be thrown which will crash and restart the
application.
Why is List View not recommended to have active
components? Clicking on the active text box will pop up the
software keyboard but this will resize the list, removing
focus from the clicked element.
Open Source
What is the Android Open Source Project?
We use the phrase "Android Open Source Project" or
"AOSP" to refer to the people, the processes, and the
source code that make up Android.
The people oversee the project and develop the actual
source code.
The processes refer to the tools and
procedures we use to manage the development of the
software.
The net result is the source code that you can
use to build cell phone and other devices.
Why did we open the Android source code?
Google started the Android project in response to our own
experiences launching mobile apps. We wanted to make
sure that there would always be an open platform available
for carriers, OEMs, and developers to use to make their
innovative ideas a reality.
We also wanted to make sure
that there was no central point of failure, so that no single
industry player could restrict or control the innovations of
any other.
The single most important goal of the Android
Open-Source Project (AOSP) is to make sure that the open-
source Android software is implemented as widely and
compatibly as possible, to everyone's benefit.
You can find more information on this topic at our Project
Philosophy page.
What kind of open-source project is Android?
Google oversees the development of the core Android
open-source platform, and works to create robust
developer and user communities. For the most part the
Android source code is licensed under the permissive
Apache Software License 2.0, rather than a "copyleft"
license.
The main reason for this is because our most
important goal is widespread adoption of the software, and
we believe that the ASL2.0 license best achieves that goal.
You can find more information on this topic at our Project
Philosophy and Licensing pages.
Why is Google in charge of Android?
Launching a software platform is complex. Openness is
vital to the long-term success of a platform, since
openness is required to attract investment from developers
and ensure a level playing field. However, the platform
itself must also be a compelling product to end users.
That's why Google has committed the professional
engineering resources necessary to ensure that Android is
a fully competitive software platform. Google treats the
Android project as a full-scale product development
operation, and strikes the business deals necessary to
make sure that great devices running Android actually
make it to market.
By making sure that Android is a success with end users,
we help ensure the vitality of Android as a platform, and as
an open-source project. After all, who wants the source
code to an unsuccessful product?
Google's goal is to ensure a successful ecosystem around
Android, but no one is required to participate, of course.
We
opened the Android source code so anyone can modify and
distribute the software to meet their own needs.
What is Google's overall strategy for Android product
development?
We focus on releasing great devices into a competitive
marketplace, and then incorporate the innovations and
enhancements we made into the core platform, as the next
version.
In practice, this means that the Android engineering team
typically focuses on a small number of "flagship" devices,
and develops the next version of the Android software to
support those product launches. These flagship devices
absorb much of the product risk and blaze a trail for the
broad OEM community, who follow up with many more
devices that take advantage of the new features.
In this
way, we make sure that the Android platform evolves
according to the actual needs of real-world devices.