An introduction to the development of Android Studio NDK

Environment:

Android Studio 1.1.0

ndk-r10d

1. New Project---"Package name: COM.MXL.AZ.NDK

To create a new class that contains the native method: Jnioperation.class

 Public class jnioperation {    publicstaticnative  String getString ();      Public native int Add (intint  b);}

2. Then use the Javah command to generate the. h file

Open "small black box", enter the project directory of .../app/build/intermediates/classes/debug/

Javah-jni com.mxl.az.ndk.JniOperation

After the command is executed, the. h file is generated in the debug directory

3. Create a new JNI folder in the Src/main directory

Copy the. h file to the Jni folder

4. Create a new Main.c,include-->.h file and implement the two methods

#include"Com_mxl_az_ndk_jnioperation.h"#include<android/log.h>#defineLog_tag "Hellojni"#defineLogi (...) __android_log_print (android_log_info,log_tag,__va_args__)#defineLOGE (...) __android_log_print (android_log_error,log_tag,__va_args__)jniexport jstring jnicall java_com_mxl_az_ndk_jnioperation_getstring (jnienv*env, Jclass CLA) {    inti; intSize =4;  for(i=0; i<size; i++) {Logi ("MXL"); }    return(*env)->newstringutf (env,"results of the JNI operation:");} Jniexport jint jnicall java_com_mxl_az_ndk_jnioperation_add (jnienv*env, Jobject obj, jint A, jint b) {  returnA +b;}

5. Configure the NDK path in local.properties

ndk.dir=/users/mxl/android/android-ndk-r10d

6. Configure the NDK in the Build.gradle file

Defaultconfig {minsdkversion8targetsdkversion AVersioncode1Versionname"1.0"NDK {abifilter"Armeabi"ModuleName"Hellojni"Ldlibs"Log","Z","m","Jnigraphics","Android"        }    }

7, load the library in the activity, run

1  Public classMainactivityextendsactionbaractivity {2 3     Static {4System.loadlibrary ("Hellojni");5     }6 7     PrivateTextView TV;8 9 @OverrideTen     protected voidonCreate (Bundle savedinstancestate) { One         Super. OnCreate (savedinstancestate); A Setcontentview (r.layout.activity_main); -  -TV =(TextView) Findviewbyid (r.id.tv); theJnioperation jnioperation =Newjnioperation (); -Tv.settext (jnioperation.getstring () + Jnioperation.add (2,8)); -     } -}

An introduction to the development of Android Studio NDK