Android Developers

DDMS (Dalvik Debug Monitor Service)

A GUI debugging application included with the SDK. It provides screen capture, log dump, and process examination capabilities. If you are developing in Eclipse using the ADT Plugin, it is integrated into your development environment.

SurfaceView

A View object that wraps a Surface for drawing, and exposes methods to specify its size and format dynamically. A ____ provides a way to draw independently of the UI thread for resource-intensive operations (such as games or camera previews), but it uses extra memory as a result. ____ supports both Canvas and OpenGL ES graphics. The base class is ____.

Activity

A single screen in an application, with supporting Java code, derived from the ____ class. Most commonly, an ____ is visibly represented by a full screen window that can receive and handle UI events and perform complex tasks, because of the Window it uses to render its window. Though an ____ is typically full screen, it can also be floating or transparent.

Layout Resource

An XML file that describes the layout of an Activity screen.

Service

An object of class ____ that runs in the background (without any UI presence) to perform various persistent actions, such as playing music or monitoring network activity.

URI

Android uses ____ strings as the basis for requesting data in a content provider (such as to retrieve a list of contacts) and for requesting actions in an Intent (such as opening a Web page in a browser). The ____ scheme and format is specialized according to the type of use, and an application can handle specific ____ schemes and strings in any way it wants. Some ____ schemes are reserved by system components. For example, requests for data from a content provider must use the content://. In an Intent, a ____ using an http:// scheme will be handled by the browser.

Window

In an Android application, an object derived from the abstract class ____ that specifies the elements of a generic window, such as the look and feel (title bar text, location and content of menus, and so on). Dialog and Activity use an implementation of this class to render a window. You do not need to implement this class or use windows in your application.

Resources

Nonprogrammatic application components that are external to the compiled application code, but which can be loaded from application code using a well-known reference format. Android supports a variety of ____ types, but a typical application's ____ would consist of UI strings, UI layout components, graphics or other media files, and so on. An application uses ____ to efficiently support localization and varied device profiles and states. For example, an application would include a separate set of ____ for each supported local or device type, and it could include layout ____ that are specific to the current screen orientation (landscape or portrait).

Widget

One of a set of fully implemented View subclasses that render form elements and other UI components, such as a text box or popup menu. Because a ____ is fully implemented, it handles measuring and drawing itself and responding to screen events. Widgets are all in the android.____ package.

ADB (Android Debug Bridge)

A command-line debugging application included with the SDK. It provides tools to browse the device, copy tools on the device, and forward ports for debugging. If you are developing in Eclipse using the ADT Plugin, ____ is integrated into your development environment.

Drawable

A compiled visual resource that can be used as a background, title, or other part of the screen. A ____ is typically loaded into another UI element, for example as a background image. A ____ is not able to receive events, but does assign various other properties such as "state" and scheduling, to enable subclasses such as animation objects or image libraries. Many ____ objects are loaded from ____ resource files — xml or bitmap files that describe the image. ____ resources are compiled into subclasses of android.graphics.____.

Viewgroup

A container object that groups a set of child Views. The ____ is responsible for deciding where child views are positioned and how large they can be, as well as for calling each to draw itself when appropriate. Some ____s are invisible and are for layout only, while others have an intrinsic UI (for instance, a scrolling list box). ____s are all in the widget package, but extend ____.

Content Provider

A data-abstraction layer that you can use to safely expose your application's data to other applications. A ____ ____ is built on the ContentProvider class, which handles content query strings of a specific format to return data in a specific format.

Action

A description of something that an Intent sender wants done. An ____ is a string value assigned to an Intent. ____ strings can be defined by Android or by a third-party developer. For example, android.intent.____.VIEW for a Web URL, or com.example.rumbler.SHAKE_PHONE for a custom application to vibrate the phone.

canvas

A drawing surface that handles compositing of the actual bits against a Bitmap or Surface object. It has methods for standard computer drawing of bitmaps, lines, circles, rectangles, text, and so on, and is bound to a Bitmap or Surface. It is the simplest, easiest way to draw 2D objects on the screen. However, it does not support hardware acceleration, as OpenGL ES does. The base class is ____.

Intent Filter

A filter object that an application declares in its manifest file, to tell the system what types of Intents each of its components is willing to accept and with what criteria. Through an ____ ____, an application can express interest in specific data types, Intent actions, URI formats, and so on. When resolving an Intent, the system evaluates all of the available ____ ____ in all applications and passes the Intent to the application/activity that best matches the Intent and criteria.

Dialog

A floating window that that acts as a lightweight form. A ____ can have button controls only and is intended to perform a simple action (such as button choice) and perhaps return a value. It is not intended to persist in the history stack, contain complex layout, or perform complex actions. Android provides a default simple ____ for you with optional buttons, though you can define your own dialog layout.

Nine-patch / 9-patch / Ninepatch image

A resizeable bitmap resource that can be used for backgrounds or other images on the device.

Theme

A set of properties (text size, background color, and so on) bundled together to define various default display settings. Android provides a few standard ____s, listed in R.style (starting with "Theme_").

Manifest File

An XML file that each application must define, to describe the application's package name, version, components (activities, intent filters, services), imported libraries, and describes the various activities, and so on.

Broadcast Receiver

An application class that listens for Intents that are broadcast, rather than being sent to a single target application/activity. The system delivers a broadcast Intent to all interested ____ ____s, which handle the Intent sequentially.

Intent

An message object that you can use to launch or communicate with other applications/activities asynchronously. An ____ object is an instance of ____. It includes several criteria fields that you can supply, to determine what application/activity receives the ____ and what the receiver does when handling the ____. Available criteria include the desired action, a category, a data string, the MIME type of the data, a handling class, and others. An application sends an ____ to the Android system, rather than sending it directly to another application/activity. The application can send the ____ to a single target application or it can send it as a broadcast, which can in turn be handled by multiple applications sequentially. The Android system is responsible for resolving the best-available receiver for each ____, based on the criteria supplied in the ____ and the ____ Filters defined by other applications.

Surface

An object of type ____ representing a block of memory that gets composited to the screen. A ____ holds a Canvas object for drawing, and provides various helper methods to draw layers and resize the surface. You should not use this class directly; use SurfaceView instead.

View

An object that draws to a rectangular area on the screen and handles click, keystroke, and other interaction events. A ____ is a base class for most layout components of an Activity or Dialog screen (text boxes, windows, and so on). It receives calls from its parent object (see viewgroup, below)to draw itself, and informs its parent object about where and how big it would like to be (which may or may not be respected by the parent).

.apk file

Android application package file. Each Android application is compiled and packaged in a single file that includes all of the application's code (.dex files), resources, assets, and manifest file. The application package file can have any name but must use this extension.

OpenGL

Android provides OpenGL ES libraries that you can use for fast, complex 3D images. It is harder to use than a Canvas object, but better for 3D objects. The android.opengl and javax.microedition.khronos.opengles packages expose ____ ES functionality.

.dex

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

Application

From a component perspective, an Android ____ consists of one or more activities, services, listeners, and intent receivers. From a source file perspective, an Android ____ consists of code, resources, assets, and a single manifest. During compilation, these files are packaged in a single file called an ____ package file (.apk).

Dalvik

The Android platform's virtual machine. The ____ VM is an interpreter-only virtual machine that executes files in the ____ Executable (.dex) format, a format that is optimized for efficient storage and memory-mappable execution. 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-compliant operating systems, which it relies on for underlying functionality (such as threading and low level memory management). The ____ 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.

Android Debug Bridge

a versatile command line tool that lets you communicate with an emulator instance or connected Android-powered device.