Performing NDK programs with Android Studio

Recently, we are ready to study the Android dual-process daemon, because it was used to write the JNI habit with eclipse. Today it is mainly used as tools. Try to write a demo here and then study the two-process daemon.

1. Required Tools

Android Studio 1.4
ndk:android-ndk-r9d
.... The other must not be described here

2, Demo sample introduction 1), Project creation

Open as to create a project input package name Com.cayden.jnis
It is assumed that the layout and activity generated with as will fail in execution.
Details may be explained in the question section

2), creating a JNI Java class

Java calls to C + + requires JNI Intermediate bridge
Detailed code such as the following

package com.cayden.jnis;/** * Created by cuiran on 16/2/27. */publicclass JniUtils {    publicnativegetCLanguageString();    static {        System.loadLibrary("JniUtils");    }}

3), generate h create C file

Need to compile the class file to generate the corresponding H file
See the commands in the picture in detail
Into the build/intermediates/classes/debug.

Then create the Jni folder under Src/main, cut the previously generated file Com_cayden_jnis_jniutils.h to this folder, and new file jnitest.c

//// Created by 崔冉 on 16/2/27.//"com_cayden_jnis_JniUtils.h"/* * Class:     com_cayden_jnis_JniUtils * Method:    getCLanguageString * Signature: ()Ljava/lang/String; */JNIEXPORT jstring JNICALL Java_com_cayden_jnis_JniUtils_getCLanguageString        (JNIEnv *env, jobject obj){    return (*env)->NewStringUTF(env,"I‘m jni");}

4), change activity and make calls

Detailed reference Code

 PackageCom.cayden.jnis;Importandroid.app.Activity;ImportAndroid.os.Bundle;ImportAndroid.widget.TextView; Public  class mainactivity extends Activity {    @Override    protected void onCreate(Bundle savedinstancestate) {Super. OnCreate (Savedinstancestate);        Setcontentview (R.layout.activity_main); Jniutils jniutils=NewJniutils ();        TextView tv= (TextView) Findviewbyid (R.id.textview); Tv.settext ("JNI Result:"+jniutils.getclanguagestring ()); }}

5), configure the NDK and its generated so file name

Add ndk.dir=/users/cuiran/tool/android-ndk-r9d to local.properties file
Change Build.gradle file

Apply plugin:' Com.android.application 'Android {Compilesdkversion +Buildtoolsversion' 19.1.0 'Defaultconfig {ApplicationID"Com.cayden.jnis"Minsdkversion -Targetsdkversion atVersioncode1Versionname"1.0"} buildtypes {release {minifyenabledfalseProguardfiles Getdefaultproguardfile (' Proguard-android.txt '),' Proguard-rules.pro 'ndk{ModuleName"Jniutils"             //generated so nameAbifilters"Armeabi","armeabi-v7a","x86"  //output specifies the so library under three ABI architectures. }} debug{ndk{modulename"Jniutils"             //generated so nameAbifilters"Armeabi","armeabi-v7a","x86"  //output specifies the so library under three ABI architectures. }}}}dependencies {compile Filetree (dir:' Libs ', include: [' *.jar '])}

3. Execution effect

After execution, shows the content written in C I ' m jni

But go back to the project folder to find that the generated so file is not seen but we will be able to see the APK anti-compilation. Seems to be quite powerful.
Can look at the anti-compiled

4, problem finishing 1) Error: "NDK integration is deprecated in the current plugin"

Workaround: Open the Gradle.properties file under the project folder. and write the following line in the file:
Android.usedeprecatedndk=true
No accident, compile the PROJECT,NDK environment again this piece is OK.

2) Error: Error:jni.h:no such file or directory

Workaround: Change compilesdkversion and Targetsdkversion to 19 to compile and pass the

Performing NDK programs with Android Studio