com.badlogic.gdx

Interface Application

public interface Application

An Application is the main entry point of your project. It sets up a window and rendering surface and manages the different aspects of your application, namely Graphics, Audio, Input and Files. Think of an Application being equivalent to Swing's JFrame or Android's Activity.

An application can be an instance of any of the following:

• a desktop application (see JglfwApplication found in gdx-backends-jglfw.jar)
• an Android application (see AndroidApplication found in gdx-backends-android.jar)
• a HTML5 application (see GwtApplication found in gdx-backends-gwt.jar)
• an iOS application (see IOSApplication found in gdx-backends-robovm.jar)

Each application class has it's own startup and initialization methods. Please refer to their documentation for more information.

While game programmers are used to having a main loop, libgdx employs a different concept to accommodate the event based nature of Android applications a little more. You application logic must be implemented in a ApplicationListener which has methods that get called by the Application when the application is created, resumed, paused, disposed or rendered. As a developer you will simply implement the ApplicationListener interface and fill in the functionality accordingly. The ApplicationListener is provided to a concrete Application instance as a parameter to the constructor or another initialization method. Please refer to the documentation of the Application implementations for more information. Note that the ApplicationListener can be provided to any Application implementation. This means that you only need to write your program logic once and have it run on different platforms by passing it to a concrete Application implementation.

The Application interface provides you with a set of modules for graphics, audio, input and file i/o.

Graphics offers you various methods to output visuals to the screen. This is achieved via OpenGL ES 2.0 or 3.0 depending on what's available an the platform. On the desktop the features of OpenGL ES 2.0 and 3.0 are emulated via desktop OpenGL. On Android the functionality of the Java OpenGL ES bindings is used.

Audio offers you various methods to output and record sound and music. This is achieved via the Java Sound API on the desktop. On Android the Android media framework is used.

Input offers you various methods to poll user input from the keyboard, touch screen, mouse and accelerometer. Additionally you can implement an InputProcessor and use it with Input.setInputProcessor(InputProcessor) to receive input events.

Files offers you various methods to access internal and external files. An internal file is a file that is stored near your application. On Android internal files are equivalent to assets. On the desktop the classpath is first scanned for the specified file. If that fails then the root directory of your application is used for a look up. External files are resources you create in your application and write to an external storage. On Android external files reside on the SD-card, on the desktop external files are written to a users home directory. If you know what you are doing you can also specify absolute file names. Absolute filenames are not portable, so take great care when using this feature.

Net offers you various methods to perform network operations, such as performing HTTP requests, or creating server and client sockets for more elaborate network programming.

The Application also has a set of methods that you can use to query specific information such as the operating system the application is currently running on and so forth. This allows you to have operating system dependent code paths. It is however not recommended to use this facilities.

The Application also has a simple logging method which will print to standard out on the desktop and to logcat on Android.

Author:

mzechner

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	Application.ApplicationType Enumeration of possible Application types

Field Summary

Fields

Modifier and Type	Field and Description
static int	LOG_DEBUG
static int	LOG_ERROR
static int	LOG_INFO
static int	LOG_NONE

Method Summary

Methods

Modifier and Type	Method and Description
void	addLifecycleListener(LifecycleListener listener) Adds a new LifecycleListener to the application.
void	debug(String tag, String message) Logs a debug message to the console or logcat
void	debug(String tag, String message, Throwable exception) Logs a debug message to the console or logcat
void	error(String tag, String message) Logs an error message to the console or logcat
void	error(String tag, String message, Throwable exception) Logs an error message to the console or logcat
void	exit() Schedule an exit from the application.
ApplicationListener	getApplicationListener()
Audio	getAudio()
Clipboard	getClipboard()
Files	getFiles()
Graphics	getGraphics()
Input	getInput()
long	getJavaHeap()
int	getLogLevel() Gets the log level.
long	getNativeHeap()
Net	getNet()
Preferences	getPreferences(String name) Returns the Preferences instance of this Application.
Application.ApplicationType	getType()
int	getVersion()
void	log(String tag, String message) Logs a message to the console or logcat
void	log(String tag, String message, Throwable exception) Logs a message to the console or logcat
void	postRunnable(Runnable runnable) Posts a Runnable on the main loop thread.
void	removeLifecycleListener(LifecycleListener listener) Removes the LifecycleListener.
void	setLogLevel(int logLevel) Sets the log level.

Field Detail

LOG_NONE

static final int LOG_NONE

See Also:

Constant Field Values

LOG_DEBUG

static final int LOG_DEBUG

See Also:

Constant Field Values

LOG_INFO

static final int LOG_INFO

See Also:

Constant Field Values

LOG_ERROR

static final int LOG_ERROR

See Also:

Constant Field Values

Method Detail

getApplicationListener

ApplicationListener getApplicationListener()

Returns:

the ApplicationListener instance

getGraphics

Graphics getGraphics()

Returns:

the Graphics instance

getAudio

Audio getAudio()

Returns:

the Audio instance

getInput

Input getInput()

Returns:

the Input instance

getFiles

Files getFiles()

Returns:

the Files instance

getNet

Net getNet()

Returns:

the Net instance

log

void log(String tag,
       String message)

Logs a message to the console or logcat

log

void log(String tag,
       String message,
       Throwable exception)

Logs a message to the console or logcat

error

void error(String tag,
         String message)

Logs an error message to the console or logcat

error

void error(String tag,
         String message,
         Throwable exception)

Logs an error message to the console or logcat

debug

void debug(String tag,
         String message)

Logs a debug message to the console or logcat

debug

void debug(String tag,
         String message,
         Throwable exception)

Logs a debug message to the console or logcat

setLogLevel

void setLogLevel(int logLevel)

Sets the log level. LOG_NONE will mute all log output. LOG_ERROR will only let error messages through. LOG_INFO will let all non-debug messages through, and LOG_DEBUG will let all messages through.

Parameters:

logLevel - LOG_NONE, LOG_ERROR, LOG_INFO, LOG_DEBUG.

getLogLevel

int getLogLevel()

Gets the log level.

getType

Application.ApplicationType getType()

Returns:

what Application.ApplicationType this application has, e.g. Android or Desktop

getVersion

int getVersion()

Returns:

the Android API level on Android, the major OS version on iOS (5, 6, 7, ..), or 0 on the desktop.

getJavaHeap

long getJavaHeap()

Returns:

the Java heap memory use in bytes

getNativeHeap

long getNativeHeap()

Returns:

the Native heap memory use in bytes

getPreferences

Preferences getPreferences(String name)

Returns the Preferences instance of this Application. It can be used to store application settings across runs.

Parameters:

name - the name of the preferences, must be useable as a file name.

Returns:

the preferences.

getClipboard

Clipboard getClipboard()

postRunnable

void postRunnable(Runnable runnable)

Posts a Runnable on the main loop thread.

Parameters:

runnable - the runnable.

exit

void exit()

Schedule an exit from the application. On android, this will cause a call to pause() and dispose() some time in the future, it will not immediately finish your application.

addLifecycleListener

void addLifecycleListener(LifecycleListener listener)

Adds a new LifecycleListener to the application. This can be used by extensions to hook into the lifecycle more easily. The ApplicationListener methods are sufficient for application level development.

Parameters:

listener -

removeLifecycleListener

void removeLifecycleListener(LifecycleListener listener)

Removes the LifecycleListener.

Parameters:

listener -