3. Eclipse Installation
• Download & Install Eclipse
▫ Select the classic version from
http://www.eclipse.org/downloads/
▫ CDT for C/C++ development is recommended
Select “Install New Software” from Eclipse’ Help menu
Select available software sites
Check CDT
Install CDT components
4. SDK Installation
• Download & Install SDK (select windows option)
▫ http://developer.android.com/sdk/index.html
• Install the ADT (Android Developer Tools) for Eclipse
▫ Instructions:
▫ http://developer.android.com/sdk/eclipse-adt.html#installing
▫ Press Add in available software menu
▫ Add ADT with the link below
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5. USB Driver / NDK Installations
• Install USB Driver
▫ If you don’t have a nexus phone download driver
from vendor. Instructions:
http://developer.android.com/sdk/oem-usb.html#InstallingDriver
• Install NDK
▫ http://developer.android.com/sdk/ndk/index.html
• Preferably do all Installations in D:Android
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6. Cygwin Installation
• Goo to http://cygwin.com/ and download setup
• Install Cygwin.
• Select default install options
• After installation, add the following Dirs to
Cygwin Path:
▫ C:Androidandroid-sdktools
▫ C:Androidandroid-ndk-r7buildtools
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8. Running a native sample app
• In Eclipse, Select:
▫ File->New->Project->Android
Project
• Select “Create Project From
Existing Source”
• change the directory to the
Installed NDK samples:
• D:Androidandroid-ndk-
r7samplesHello-Jni
• Select target and finish
9. Compile & Run
• Compile the Java application
• Run it on your phone target
• Crash?
• Open Cygwin window
• Compile the native code in:
D:Androidandroid-ndk-r7samplesHello-Jni
JNI using ndk-build command
• Compile the Java application
• Run it on your target
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11. Java Code Review
• Java part of the application is simple:
• On create, the application prints to the screen a
string it receives from stringFromJNI() declared
as a Native function
• Native library hello-jni is loaded
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12. Java to C calling convention
/* sample method where the Java call passed no parameters */
void Java_ClassName_MethodName (JNIEnv *env, jobject obj)
{/* do something */ }
/* another sample method with two parameters passed, returning
a double */
jdouble Java_ClassName_MethodName ( JNIEnv* env, jobject obj,
jdouble x, jdouble y)
{ return x + y; }
• Note: Android Java identifies the native functions according to their
C type signature. If the call is for CPP functions, the Java program
will not recognize them. The solution to this problem is to use
extern “C” { } around the CPP functions
13. Make Files
• Android native applications must could have two
make files:
▫ Android.mk – details the source header and
libraries used to create the application (library)
▫ Application.mk – details the target platform,
processor (ARM 7) and API level (API 10). The
application.mk file is not mandatory
14. Android.mk Sample
Example, the HelloJNI NDK sample make File
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := hello-jni
LOCAL_SRC_FILES := hello-jni.c
include $(BUILD_SHARED_LIBRARY)
15. Android.mk Review
• LOCAL_PATH := $(call my-dir)
▫ first understand where we are since include paths
are usually RELATIVE to our current location.
This must be the first command in the mk file
• CLEAR_VARS - clears special GNU Makefile
LOCAL_XXX variables like LOCAL_SRC_FILES
• LOCAL_MODULE := hello-jni
The LOCAL_MODULE variable must be defined
to identify each module you describe in your
Android.mk. The name must be *unique*
without spaces.
16. Application.mk Review
• The hello-jni sample does not include
application.mk file.
• Application.mk can define the target platform as
9 (Android 2.2) APP_PLATFORM := android-9
• Application file can also define the processor
version:
# Build both ARMv5TE and ARMv7-A machine code.
APP_ABI := armeabi armeabi-v7a
17. Refrences
• Review of Android Make file
• Native android development
• Cygwin Install for Android
