Thursday, June 11, 2015

Android Words Meanings Lecture 2

What is .dex extension
Android programs are compiled into .dex (Dalvik
Executable) files, which are in turn zipped into a single .apk
file on the device. .dex files can be created by automatically
translating compiled applications written in the Java
programming language

What is an adb ?
Android Debug Bridge, a command-line debugging
application shipped with the SDK. It provides tools to
browse the device, copy tools on the device, and forward
ports for debugging.

What is an Application ?
A collection of one or more activities, services, listeners,
and intent receivers.
An application has a single manifest,
and is compiled into a single .apk file on the device.

What is a Content Provider ?
A class built on ContentProviderthat handles content query
strings of a specific format to return data in a specific
format. See Reading and writing data to a content provider
for information on using content providers.

What is a Dalvik ?
The name of Android's virtual machine. The Dalvik VM is
an interpreter-only virtual machine that executes files in the
Dalvik Executable (.dex) format, a format that is optimized
for efficient storage and memory-mappableexecution.
The
virtual machine is register-based,and it can run classes
compiled by a Java language compiler that have been
transformed into its native format using the included "dx"
tool. The VM runs on top of Posix-compliantoperating
systems, which it relies on for underlying functionality
(such as threading and low level memory management).
The Dalvik core class library is intended to provide a
familiar development base for those used to programming
with Java Standard Edition, but it is geared specifically to
the needs of a small mobile device.

What is an DDMS
Dalvik Debug Monitor Service, a GUI debugging application
shipped with the SDK.
It provides screen capture, log dump,
and process examination capabilities.
What is Drawable?
A compiled visual resource that can be used as a
background, title, or other part of the screen. It is compiled
into an android.graphics.drawable subclass.
What is an Intent?
A class (Intent) that contains several fields describing what
a caller would like to do. The caller sends this intent to
Android's intent resolver, which looks through the intent
filters of all applications to find the activity most suited to
handle this intent. Intent fields include the desired action, a
category, a data string, the MIME type of the data, a
handling class, and other restrictions.

What is an Intent Filter ?
Activities and intent receivers include one or more filters in
their manifest to describe what kinds of intents or
messages they can handle or want to receive. An intent
filter lists a set of requirements, such as data type, action
requested, and URI format, that the Intent or message must
fulfill. For Activities, Android searches for the Activity with
the most closely matching valid match between the Intent
and the activity filter.
For messages, Android will forward a
message to all receivers with matching intent filters.

What is an Intent Receiver?
An application class that listens for messages broadcast by
calling Context.broadcastIntent
What is a Layout resource?
An XML file that describes the layout of an Activity screen.

What is a Manifest ?
An XML file associated with each Application that describes
the various activies, intent filters, services, and other items
that it exposes.

What is a Resource
A user-supplied XML, bitmap, or other file, entered into an
application build process, which can later be loaded from
code. Android can accept resources of many types; see
Resources for a full description. Application-defined
resources should be stored in the res/ subfolders.

What is a Service ?
A class that runs in the background to perform various
persistent actions, such as playing music or monitoring
network activity.

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