How to install Android NDK on windows

This article teaches how to install Android NDK in Eclipse on windows, and setup the configuration for auto-build JNI native library(.so).

Step1:First, you already install Android SDK on you PC.
Step2:The difference between Android SDK and Android NDK, Android SDK is to create a pure JAVA code application, and Android NDK is to create a JAVA application with the native library. The native library is a dynamic library. JAVA call the library through the JNI interface.
Step3:The NDK content a cross compiler toolchain, must runs on the linux environment. The Cygwin create a linux-link environment on windows. This article shows How to install Cygwin on windows.
Step4:Download the NDK from the office web site.
android-ndk-r8-windows.zip
Step5:Unzipped the android-ndk-r8-windows.zip to the Cygwin root directory.

Step6:Append the path define code to the .bash_profile in the I:\cygwin\home\{US ER NAME}\.bash_profile.

PATH=/android-ndk-r8:${PATH}
NDK_ROOT=/android-ndk-r8
NDK_Sample=/android-ndk-r8/samples
export PATH NDK_ROOT NDK_Sample

Step7:Click the batch file I:\cygwin\Cygwin.bat, enter Cygwin shell.
Change current Directory to the /android-ndk-r8/samples/hello-jni/, and run the ndk-build command. The library ibhello-jni.so will be created.

Step8:When the library shows up. That means the environment of your Android NDK is ok.

Step9:Let's start the real project of the Android. In the Eclipse we can open the exist project "hello-jni" from the NDK samples directory.

Step10:In the Package Explorer, we can find the libs directory include the library libhello-jni.so we create before.

Step11:Now we need setup some configuration to create a auto-build environment.
     Enter project properties->Builders page, we create a new program builder.

Step12:Click OK to the next window, fill the text with specific info.
     Name: JNI_Builder
     Locations:I:\cygwin\bin\bash.exe
     Working Directory:I:\cygwin\bin
     Arguments: --login -c "cd $NDK_Sample/hello-jni && ndk-build"

Step13:Switch to the Refersh page, checked Refresh resources upon completion and Specific resources.

Step14:In the pop-up window, we checked the libs directory. And click Finish back to the Edit Configuration window.

Step15:Switch to the Build Options page. Checked these options.

     Allocate Console
     Launch in background
     After a "Clean"
     During manual builds
     During auto builds
     Specify working set if relevant resources.

Step16:Click the Specific Resources, We checked the jni directory.

Step17:Click the finish button, and in the Builders page, it has a new program named "JNI_Builder".

Step18:Click OK button, back to the Eclipse main page.
Step19:Edit the hello-jni.c file, then save. The JNI-Builder will start to compile native library. And the native library will be packed into the Android APK.