jni function missing

Question

Hi,

While compiling the android-studio project the .so file is not creating. Can anyone please tell me what will be the problem.

Progesterony · Answer

1.**Create directories** Inside /app/src/main create a jni and jniLibs directory. 2.**Update local.properties** Inside your local.properties file, add a line similar to: ndk.dir=/home/user/development/bin/android-ndk-r10e 3. **Update build.gradle** something like this : apply plugin: 'com.android.model.application' model { android { compileSdkVersion = 23 buildToolsVersion = "23.0.0" defaultConfig.with { applicationId = "com.example.hellojni" minSdkVersion.apiLevel = 4 targetSdkVersion.apiLevel = 23 } } compileOptions.with { sourceCompatibility=JavaVersion.VERSION_1_7 targetCompatibility=JavaVersion.VERSION_1_7 } /* * native build settings */ android.ndk { moduleName = "hello-jni" /* * Other ndk flags configurable here are * cppFlags += "-fno-rtti" * cppFlags += "-fno-exceptions" * ldLibs = ["android", "log"] * stl = "system" */ } android.buildTypes { release { minifyEnabled = false proguardFiles += file('proguard-rules.txt') } } android.productFlavors { // for detailed abiFilter descriptions, refer to "Supported ABIs" @ // https://developer.android.com/ndk/guides/abis.html#sa create("arm") { ndk.abiFilters += "armeabi" } create("arm7") { ndk.abiFilters += "armeabi-v7a" } create("arm8") { ndk.abiFilters += "arm64-v8a" } create("x86") { ndk.abiFilters += "x86" } create("x86-64") { ndk.abiFilters += "x86_64" } create("mips") { ndk.abiFilters += "mips" } create("mips-64") { ndk.abiFilters += "mips64" } // To include all cpu architectures, leaves abiFilters empty create("all") } } 4. **You will need an Android.mk file inside the /app/src/main/jni directory** LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := test LOCAL_SRC_FILES := test.cpp LOCAL_LDLIBS := -llog include $(BUILD_SHARED_LIBRARY) 5. **test.cpp** Add some awesome C/C++ source code for your lib. These files will start in /app/src/main/jni and will be compiled and linked as specified in your Android.mk example : #include #include static const char *SOME_TAG = "MyAwesomeTag"; extern "C" { void Java_com_something_something_1android_ClassName_some_fn(JNIEnv *env, jobject obj) { __android_log_print(ANDROID_LOG_VERBOSE, SOME_TAG, "Hello from NDK :)"); } } Compile and run. this solution is compiled by several stackoverflow threads Good luck

Gayathri Sekaran · Answer

Posting my logcat for your reference.

> 09-12 10:29:29.830 7401-7401/? D/ToggleAccessibilityServicePreferenceFragment: mComponentName.getPackageName : com.example.vinay.screenreader
09-12 10:29:34.806 2908-2992/? D/MARsPolicyManager: getEnabledAccessibilityPackage: add mEnabledAccessibilityPackages com.example.vinay.screenreader
09-12 10:29:34.814 2908-2908/? I/AccessibilityManagerService: isTalkbackEnable : false, accesibilityService : com.example.vinay.screenreader/com.example.vinay.screenreader.MyScreenReaderService
09-12 10:29:34.851 7401-7401/? D/ToggleAccessibilityServicePreferenceFragment: mComponentName : ComponentInfo{com.example.vinay.screenreader/com.example.vinay.screenreader.MyScreenReaderService} false
> 
>ndk path in local.properties
ndk.dir=/home/gayathri/Android/Sdk/ndk-bundle
sdk.dir=/home/gayathri/Android/Sdk
> 
> Application.mk

APP_ABI := all

> Android.mk

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE    := mainfn
LOCAL_SRC_FILES := mainfn.c my_flite_hts_imp.c us_int_accent_cart.c us_int_tone_cart.c us_nums_cart.c us_phrasing_cart.c us_pos_cart.c transliterator.c
LOCAL_LDLIBS +=  -lm -llog

include $(BUILD_SHARED_LIBRARY)

> apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "com.example.vinay.screenreader"
        minSdkVersion 21
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
        ndk
                {
                    moduleName "mainfn"
                }
    }


    sourceSets.main
            {
                jni.srcDirs = [];
                jniLibs.srcDir 'src/main/libs'
            }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

> 
> 
> mainfn.c

    

#include <jni.h>

JNIEXPORT void JNICALL Java_com_example_vinay_screenreader_MyScreenReaderService_mainfn
  (JNIEnv *env, jobject obj, jstring Usertext_cont,jstring path,jstring wpath)
  {
        //jclass userClass = (*env)->GetObjectClass(env, userobject);
        //jmethodID getUsertext_cont = (*env)->GetMethodID(env, userClass, "getUsertext", "()I");
        //char* text =  (char*)(*env)->CallIntMethod(env, userobject, getUsertext_cont);
        const char *aa = (*env)->GetStringUTFChars(env, Usertext_cont, 0);
        const char *bb = (*env)->GetStringUTFChars(env, path, 0);
        const char *cc = (*env)->GetStringUTFChars(env, wpath, 0);
        char * text = strdup(aa);
        char * filepath = strdup(bb);
        char * wavpath = strdup(cc);
        int y = main_syn(text,filepath,wavpath);
        int x = num_return();
        if(y==-1)
        {
            (*env)->NewStringUTF(env,"got -1");
        }
        else
        {
 return (*env)->NewStringUTF(env, "Hello From JNI");
            (*env)->NewStringUTF(env,aa);
        }

  }