README.android
author Sam Lantinga <slouken@libsdl.org>
Thu, 06 Jan 2011 17:12:31 -0800
changeset 4965 91d0085b7560
parent 4964 6c645018741e
child 4967 f74a3f94c408
permissions -rw-r--r--
Added the Android project and lots of info to README.android

================================================================================
Simple DirectMedia Layer for Android
================================================================================

Requirements:

Android SDK
http://developer.android.com/sdk/index.html

Android NDK r4 or later
http://developer.android.com/sdk/ndk/index.html

================================================================================
 How the port works
================================================================================

- Android applications are Java-based, optionally with parts written in C
- As SDL apps are C-based, we use a small Java shim that uses JNI to talk to 
the SDL library
- This means that your application C code must be placed inside an android 
Java project, along with some C support code that communicates with Java
- This eventually produces a standard Android .apk package


================================================================================
 Building an app
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Instructions:
1. Copy the android-project directory wherever you want to keep your projects and rename it to the name of your project.
2. Move this SDL directory into the <project>/jni directory
3. Place your application source files in the <project>/jni/src directory
4. Edit <project>/jni/src/Android.mk to include your source files
5. Run 'ndk-build' (a script provided by the NDK). This compiles the C source

If you want to use the Eclipse IDE, skip to the Eclipse section below.

6. Edit <project>/local.properties to point to the Android SDK directory
7. Run 'ant debug' in android/project. This compiles the .java and eventually 
creates a .apk with the native code embedded
8. 'ant install' will push the apk to the device or emulator (if connected)

Here's an explanation of the files in the Android project, so you can customize them:

android-project/
	AndroidManifest.xml	- package manifest, do not modify
	build.properties	- empty
	build.xml		- build description file, used by ant
	default.properties	- holds the ABI for the application, currently android-4 which corresponds to the Android 1.6 system image
	local.properties	- holds the SDK path, you should change this to the path to your SDK
	jni/			- directory holding native code and Android.mk
	jni/Android.mk		- Android makefile that includes all subdirectories
	jni/SDL/		- directory holding the SDL library files
	jni/SDL/Android.mk	- Android makefile for creating the SDL shared library
	jni/src/		- directory holding your application source
	jni/src/Android.mk	- Android makefile that you should customize to include your source code and any library references
	res/			- directory holding resources for your application
	res/drawable-*		- directories holding icons for different phone hardware
	res/layout/main.xml	- place holder for the main screen layout, overridden by the SDL video output
	res/values/strings.xml	- strings used in your application, including the application name shown on the phone.
	src/org/libsdl/app/SDLActivity.java	- the Java class handling the initialization and binding to SDL.  Be very careful changing this, as the SDL library relies on this implementation.


================================================================================
 Additional documentation
================================================================================

The documentation in the NDK docs directory is very helpful in understanding the build process and how to work with native code on the Android platform.

The best place to start is with docs/OVERVIEW.TXT


================================================================================
 Using Eclipse
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First make sure that you've installed Eclipse and the Android extensions as described here:
	http://developer.android.com/sdk/eclipse-adt.html

Once you've copied the SDL android project and customized it, you can create an Eclipse project from it:
 * File -> New -> Other
 * Select the Android -> Android Project wizard and click Next
 * Enter the name you'd like your project to have
 * Select "Create project from existing source" and browse for your project directory
 * Make sure the Build Target is set to Android 1.6
 * Click Finish


================================================================================
 Loading files and resources
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NEED CONTENT


================================================================================
 Troubleshooting
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You can create and run an emulator from the Eclipse IDE:
 * Window -> Android SDK and AVD Manager

You can see if adb can see any devices with the following command:
	adb devices

You can see the output of log messages on the default device with:
	adb logcat

You can push files to the device with:
	adb push local_file remote_path_and_file

You can push files to the SD Card at /sdcard, for example:
	adb push moose.dat /sdcard/moose.dat


================================================================================
 Known issues
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- SDL audio (although it's mostly written, just not working properly yet)
- TODO. I'm sure there's a bunch more stuff I haven't thought of