Java tutorial
/******************************************************************************* * Copyright 2011 See AUTHORS file. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. ******************************************************************************/ package com.badlogic.gdx; import com.badlogic.gdx.utils.Clipboard; /** <p> * An <code>Application</code> 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 {@link Graphics}, {@link Audio}, {@link Input} and {@link Files}. Think of an * Application being equivalent to Swing's <code>JFrame</code> or Android's <code>Activity</code>. * </p> * * <p> * An application can be an instance of any of the following: * <ul> * <li>a desktop application (see <code>JglfwApplication</code> found in gdx-backends-jglfw.jar)</li> * <li>an Android application (see <code>AndroidApplication</code> found in gdx-backends-android.jar)</li> * <li>a HTML5 application (see <code>GwtApplication</code> found in gdx-backends-gwt.jar)</li> * <li>an iOS application (see <code>IOSApplication</code> found in gdx-backends-robovm.jar)</li> * </ul> * Each application class has it's own startup and initialization methods. Please refer to their documentation for more * information. * </p> * * <p> * 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 {@link 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. * </p> * * <p> * The Application interface provides you with a set of modules for graphics, audio, input and file i/o. * </p> * * <p> * {@link 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. * </p> * * <p> * {@link 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. * </p> * * <p> * {@link Input} offers you various methods to poll user input from the keyboard, touch screen, mouse and accelerometer. * Additionally you can implement an {@link InputProcessor} and use it with {@link Input#setInputProcessor(InputProcessor)} to * receive input events. * </p> * * <p> * {@link 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. * </p> * * <p> * {@link 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. * </p> * * <p> * The <code>Application</code> 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. * </p> * * <p> * The <code>Application</code> also has a simple logging method which will print to standard out on the desktop and to logcat on * Android. * </p> * * @author mzechner */ public interface Application { /** Enumeration of possible {@link Application} types * * @author mzechner */ public enum ApplicationType { Android, Desktop, HeadlessDesktop, Applet, WebGL, iOS } public static final int LOG_NONE = 0; public static final int LOG_DEBUG = 3; public static final int LOG_INFO = 2; public static final int LOG_ERROR = 1; /** @return the {@link ApplicationListener} instance */ public ApplicationListener getApplicationListener(); /** @return the {@link Graphics} instance */ public Graphics getGraphics(); /** @return the {@link Audio} instance */ public Audio getAudio(); /** @return the {@link Input} instance */ public Input getInput(); /** @return the {@link Files} instance */ public Files getFiles(); /** @return the {@link Net} instance */ public Net getNet(); /** Logs a message to the console or logcat */ public void log(String tag, String message); /** Logs a message to the console or logcat */ public void log(String tag, String message, Throwable exception); /** Logs an error message to the console or logcat */ public void error(String tag, String message); /** Logs an error message to the console or logcat */ public void error(String tag, String message, Throwable exception); /** Logs a debug message to the console or logcat */ public void debug(String tag, String message); /** Logs a debug message to the console or logcat */ public void debug(String tag, String message, Throwable exception); /** Sets the log level. {@link #LOG_NONE} will mute all log output. {@link #LOG_ERROR} will only let error messages through. * {@link #LOG_INFO} will let all non-debug messages through, and {@link #LOG_DEBUG} will let all messages through. * @param logLevel {@link #LOG_NONE}, {@link #LOG_ERROR}, {@link #LOG_INFO}, {@link #LOG_DEBUG}. */ public void setLogLevel(int logLevel); /** Gets the log level. */ public int getLogLevel(); /** @return what {@link ApplicationType} this application has, e.g. Android or Desktop */ public ApplicationType getType(); /** @return the Android API level on Android, the major OS version on iOS (5, 6, 7, ..), or 0 on the desktop. */ public int getVersion(); /** @return the Java heap memory use in bytes */ public long getJavaHeap(); /** @return the Native heap memory use in bytes */ public long getNativeHeap(); /** Returns the {@link Preferences} instance of this Application. It can be used to store application settings across runs. * @param name the name of the preferences, must be useable as a file name. * @return the preferences. */ public Preferences getPreferences(String name); public Clipboard getClipboard(); /** Posts a {@link Runnable} on the main loop thread. * * @param runnable the runnable. */ public void postRunnable(Runnable runnable); /** 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. */ public void exit(); /** Adds a new {@link LifecycleListener} to the application. This can be used by extensions to hook into the lifecycle more * easily. The {@link ApplicationListener} methods are sufficient for application level development. * @param listener */ public void addLifecycleListener(LifecycleListener listener); /** Removes the {@link LifecycleListener}. * @param listener */ public void removeLifecycleListener(LifecycleListener listener); }