无法启用JNI调试器

Question

I have started using Java Native Interface (JNI) recently and encountered some problems that I hope you could help me to solve.

I am using Android Studio 2.1.1, SDK Tools 25.1.7, NDK 12, API 21.

1.My main problem is that i cannot debug the C code, only the java. i will try to explain my attempts at debugging on a much simpler code which i will include.

1.1 I compiled the C code to .so with the command ndk-build NDK_DEBUG=1.

1.2 I have added the SDK\\NDK path to the Android Studio Project Structure.

1.3 I have added to the build.gradle "jnidebuggable=true".

1.4 I have created in Run->Edit Config a new debug session with "Hybrid" settings and loaded the .so libs to it.

1.5 Attaching my Android.mk, Application.mk, build.gradle, C code and files.

1.6 The code is running and working, it doesn't hit the breakpoints inside the C code.

2.how can i monitor the heap and stack usage of my code and especially the of the JNI? also is it changeable?

3.on the same matter as 2. how can i decrease the dependency in the heap? will defining my variables as static do the trick?

Android.mk

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := sub
LOCAL_SRC_FILES := subst.c
include $(BUILD_SHARED_LIBRARY)

Application.mk

APP_ABI := all
APP_BUILD_SCRIPT := C:\Users\Nir\AndroidStudioProjects\FirstApp\jni\Android.mk

C code

jdouble Java_nir_firstapp_MainActivity_subst(JNIEnv* env, jobject obj, jdouble A, jdouble B)
{
int x;
x=A-B;
return(x);
}

build.gradle

apply plugin: 'com.android.application'

android {
compileSdkVersion 23
buildToolsVersion "23.0.2"

defaultConfig {
    applicationId "nir.firstapp"
    minSdkVersion 19
    targetSdkVersion 23
    versionCode 1
    versionName "1.0"
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
    debug {
        jniDebuggable true
        debuggable true
    }
    }
}

MainActivity relevant code

public native double subst(double A, double B);
static{
    System.loadLibrary("sub");
}
double calc = subst(Double.valueOf(num1str),Double.valueOf(num2str));

My sincere thank you, Nir

Answer 1

To enable native debugging, compile your C++ code under Android Studio.

With version 2.2, you can use externalNativeBuild . For 2.1, you only have the experimental Gradle plugin. Unfortunately, it is not completely integrated into AS, eg File/Project Structure (aka Ctrl-; ) does not understand these build.gradle files.