Gradle无法编译NDK文件

Question

I got the source of a project (An android application) from github and I am trying to launch it, the project is called "RtkGps+" it's an Anroid application to that use a C++ libary called Rtklib to play with GPS and Raw measurements.

My Android environment configuration is bellow,

Gradle version : 3.1.3
NDK revision : 19.0.5232133

I'm unable to compile the project, I got the errors bellow :

As shown in the the capture there are many errors, that I want to enumate them,

• So the first one is this error where the NDK_PROJECT_PATH=null

SIMPLE: Error while executing process C:\Users\Yazid\AppData\Local\Android\Sdk\ndk-bundle\ndk-build.cmd with arguments {NDK_PROJECT_PATH=null APP_BUILD_SCRIPT=C:\Users\Yazid\Documents\Dev\Android\RtkGps-master\RtkGps-master\jni\Android.mk NDK_APPLICATION_MK=C:\Users\Yazid\Documents\Dev\Android\RtkGps-master\RtkGps-master\jni\Application.mk APP_ABI=armeabi-v7a NDK_ALL_ABIS=armeabi-v7a NDK_DEBUG=0 APP_PLATFORM=android-21 NDK_OUT=C:/Users/Yazid/Documents/Dev/Android/RtkGps-master/RtkGps-master/build/intermediates/ndkBuild/release/obj NDK_LIBS_OUT=C:\Users\Yazid\Documents\Dev\Android\RtkGps-master\RtkGps-master\build\intermediates\ndkBuild\release\lib APP_SHORT_COMMANDS=false LOCAL_SHORT_COMMANDS=false -B -n}

• The second one is saying that the Android.mk file is not supported

SIMPLE: Android NDK: WARNING: Unsupported source file extensions in C:\Users\Yazid\Documents\Dev\Android\RtkGps-master\RtkGps-master\jni\Android.mk for module rtklib    

I tried adding gradle code from this answer : https://stackoverflow.com/a/50707270/6306138

The Gradle file of the project.

buildscript {
    repositories {
        mavenCentral()
        jcenter()
        google()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.3'
    }
}
apply plugin: 'com.android.application'

repositories {
    mavenCentral()
    jcenter()
    google()
}

dependencies {
    implementation  group: 'cz.msebera.android' , name: 'httpclient' , version: '4.4.+'
    implementation 'com.android.support:support-v13:27.1.1'
    implementation 'com.google.gms:google-services:3.2.1'
    implementation 'com.google.android.gms:play-services-gcm:11.0.4'
    implementation 'com.google.code.findbugs:jsr305:3.0.2'
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.jakewharton:butterknife:8.8.1'
    implementation 'com.karumi:dexter:5.0.0'
    implementation 'ch.acra:acra:4.5.0'
    implementation 'commons-net:commons-net:3.6'
    implementation 'org.slf4j:slf4j-api:1.7.25'
    implementation 'com.infstory:proguard-annotations:1.0.1'
    annotationProcessor 'com.jakewharton:butterknife-compiler:8.8.1'
}

android {
    sourceSets.main.res.filter.exclude '**/proj4/jniwrap/org/**'

    lintOptions {
        checkReleaseBuilds false
        // Or, if you prefer, you can continue to check for errors in release builds,
        // but continue the build even when errors are found:
        abortOnError false
    }

    compileSdkVersion 26
    buildToolsVersion '27.0.3'
    defaultConfig {
        applicationId "gpsplus.rtkgps"
        minSdkVersion 21
        targetSdkVersion 26
        multiDexEnabled true
        ndk {
            abiFilters = []
            abiFilters.add('armeabi-v7a')
            abiFilters.add('x86')
            abiFilters.add('x86_64')
            abiFilters.add('arm64-v8a')
        }
    }
    sourceSets {
        main {
            manifest.srcFile 'AndroidManifest.xml'
            java.srcDirs = ['src']
            resources.srcDirs = ['src']
            aidl.srcDirs = ['src']
            renderscript.srcDirs = ['src']
            res.srcDirs = ['res']
            assets.srcDirs = ['assets']
            jniLibs.srcDir 'libs'
        }

           //    instrumentTest.setRoot('tests')
    }
    externalNativeBuild {
        ndkBuild {
            path 'jni/Android.mk'
        }
    }
    packagingOptions{
        doNotStrip '*/mips/*.so'
        doNotStrip '*/mips64/*.so'
    }

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_7
        targetCompatibility JavaVersion.VERSION_1_7
    }
    buildTypes {
        debug {
            debuggable true
            jniDebuggable false
            renderscriptDebuggable false

        }

    }
    productFlavors {
    }
}

Answer 1

Neither of the "errors" mentioned are errors. NDK_PROJECT_PATH=null is normal behavior for Studio, and the second is just a warning.

Without seeing your Android.mk or the full error message (the line immediately after the one you included tells you what went wrong) I can't tell you how to fix the warning, but like the warning says, one of your source files has an unrecognized extension so ndk-build didn't know how to build it.