"Android Development"-a simple example of NDK Jni development under Android Studio

Android has been developing for some time, on the one hand, feeling nothing left. A little sorry for myself,

On the other hand, good memory is inferior to bad writing, in order to later can look back, as a note, decided to start blogging. Don't say much nonsense!

Today I want to do the NDK and JNI, and now start writing a simple demo

1. Create a new project

2. Create a new class Jnitext.java click Build--make Project

Select Project Click F4 Key SDK location in Android NDK location Select Configure NDK path
No downloads available to download here: http://wear.techbrood.com/tools/sdk/ndk/


On the safe side. Click to view Local.properties file
ndk.dir=d\:\\ndk\\android-ndk-r10e
Sdk.dir=c\:\\users\\administrator\\appdata\\local\\android\\sdk
Ok so good next


View E:\text\YipJniDemo\app\build\intermediates\classes\debug in the project directory generates a class file
Next click on the Terminal window CD below to the current project directory
E:\TEXT\YIPJNIDEMO>CD E:\text\YipJniDemo\app\build\intermediates\classes\debug


using Javah to generate header files

E:\text\yipjnidemo\app\build\intermediates\classes\debug>javah-jni Com.yip.yipjnidemo.JniText


In E:\text\YipJniDemo\app\build\intermediates\classes\debug
You can see the generated com_yip_yipjnidemo_jnitext.h

1 /*Do not EDIT this file-it are machine generated*/2#include <jni.h>3 /*Header for Class Com_yip_yipjnidemo_jnitext*/4 5 #ifndef _included_com_yip_yipjnidemo_jnitext6 #define_included_com_yip_yipjnidemo_jnitext7 #ifdef __cplusplus8 extern "C" {9 #endifTen /* One * Class:com_yip_yipjnidemo_jnitext A * method:getclangstring - * Signature: () ljava/lang/string; -  */ the jniexport jstring jnicall java_com_yip_yipjnidemo_jnitext_getclangstring -(JNIENV *, jobject); -  - #ifdef __cplusplus + } - #endif + #endif

Create Jni folder under Project src file Note (right-click Main-new-folder-jnifolder)
cut the resulting file com_yip_yipjnidemo_jnitext.h into the Jni folder



Create a com_yip_yipjnidemo_jnitext.c file under the JNI directory

1#include"com_yip_yipjnidemo_jnitext.h"2 /*3 * Class:io_github_yanbober_ndkapplication_ndkjniutils4 * method:getclanguagestring5 * Signature: () ljava/lang/string;6  */7Jniexport jstring jnicall java_com_yip_yipjnidemo_jnitext_getclangstring (jnienv *env, Jobject obj)8 {9   return(*env)->newstringutf (env,"This just a test for Android Studio NDK JNI developer!");Ten}

Next, in the app's Build.gradle;

1 Add under Defaultconfig 2     ndk{3         modulename "Jnitext"         // generated so name 4             Abifilters "Armeabi", "armeabi-v7a", "x86"  // outputs specify so libraries under three ABI architectures. Currently dispensable.  5     }

Click Make-project
Build. So library
The Error was reported at this time: (0) ERROR:NDK integration is deprecated in the current plugin.  Consider trying the new experimental plugin.  For details, see Http://tools.android.com/tech-docs/new-build-system/gradle-experimental. Set "Android.usedeprecatedndk=true" in gradle.properties to continue using the current NDK integration.
<a href= "Openfile:e:\text\myjnidemo\app\build.gradle" >open file</a>
Never mind
we add properties to the Gradle.properties under the project

  Android.usedeprecatedndk=true  

this is complete. Code for Yipjnidemo under Mainactivity

1  PackageCom.yip.yipjnidemo;2 3 Importandroid.app.Activity;4 Importandroid.support.v7.app.AppCompatActivity;5 ImportAndroid.os.Bundle;6 ImportAndroid.widget.TextView;7 8  Public classMainactivityextendsActivity {9 Ten  One     PrivateTextView Txtview; A  - @Override -     protected voidonCreate (Bundle savedinstancestate) { the         Super. OnCreate (savedinstancestate); - Setcontentview (r.layout.activity_main); -txtview=(TextView) Findviewbyid (r.id.txt_jnitext); -Jnitext jnitext=NewJnitext (); + Txtview.settext (jnitext.getclangstring ()); -     } +}

Jnitext:

1  PackageCom.yip.yipjnidemo;2 3 /**4 * Created by Administrator on 2016/2/22.5  */6  Public classJnitext {7     Static {8System.loadlibrary ("Jnitext");//DefaultConfig.ndk.moduleName9         }Ten      Public nativeString getclangstring (); One}

PS: generated. So file some pots of friends can not find. In fact, it's here.

"Android Development"-a simple example of NDK Jni development under Android Studio