Develop Reference

How to set NDK lib path in Gradle?

I'm working on a PDF viewer application using ebookdroid & MuPDF CPP files. I am having lots of problem with NDK integration in Gradle. I've gone through many answers but they have not fixed my problem.
Gradle is giving me the following error message:
Error:Execution failed for task ':app:compileDebugNdk'.
Error: Your project contains C++ files but it is not using a supported native build system.
Consider using CMake or ndk-build integration with the stable Android Gradle plugin:
https://developer.android.com/studio/projects/add-native-code.html
or use the experimental plugin:
http://tools.android.com/tech-docs/new-build-system/gradle-experimental.

Edit your build.gradle, add defaultConfig.externalNativeBuild.ndkBuild, externalNativeBuild.ndkBuild and sourceSet.main.jni.srcDir options. See the comments below.
android {
compileSdkVersion 22
buildToolsVersion "27.0.0"
defaultConfig {
minSdkVersion 18
targetSdkVersion 22
versionCode 1
versionName "1.0"
//add arguments passed to ndkBuild
externalNativeBuild {
ndkBuild {
arguments "NDK_TOOLCHAIN_VERSION=clang", "APP_SHORT_COMMANDS=true", "APP_ALLOW_MISSING_DEPS=true"
arguments "-j" + Runtime.runtime.availableProcessors()
cFlags "-fexceptions"
}
}
ndk {
abiFilters "armeabi-v7a"
}
}
//specify jni source file path
sourceSets.main {
java.srcDir "src"
res.srcDir "res"
jni.srcDir "jni"
}
buildTypes {
debug {
debuggable true
jniDebuggable true
}
}
//specify makefile / CMake file
externalNativeBuild {
ndkBuild {
path 'jni/Android.mk'
}
}
}

Superpowered SDK: Error:Execution failed for task ':app:ndkBuild'. A dikkat occurred starting process 'command 'null/ndk-build''

I am trying to install Superpowered example app on my phone using Android Studio but it's not getting built. It shows an error:
Error:Execution failed for task ':app:ndkBuild'.
> A problem occurred starting process 'command 'null/ndk-build''
build.gradle code is:
apply plugin: 'com.android.application'
android {
compileSdkVersion 23
buildToolsVersion "22.0.1"
defaultConfig {
applicationId "com.superpowered.hlsexample"
minSdkVersion 16
targetSdkVersion 23
versionCode 1
versionName "1.0"
sourceSets.main {
jniLibs.srcDir 'src/main/libs'
jni.srcDirs = []
}
}
task ndkBuild(type: Exec) {
Properties properties = new Properties()
properties.load(project.rootProject.file('local.properties').newDataInputStream())
def ndkDir = properties.getProperty('ndk.dir')
commandLine "$ndkDir/ndk-build", '-B', '-C', file('src/main/jni').absolutePath
// Windows users: commandLine "$ndkDir\\ndk-build.cmd", '-B', '-C', file('src/main/jni').absolutePath
}
lintOptions {
abortOnError false
}
tasks.withType(JavaCompile) {
compileTask -> compileTask.dependsOn ndkBuild
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:appcompat-v7:22.2.0'
}
Please help me find the right solution. And/Or guide me on how to add NDK to the current app. Thanks in Advance.

Just had same problem. Solved it by entering "File -> Project Structure". For my case "Android NDK location" was empty as shown. Clicking "Select" fixed it.

Open local.properties. Set ndk.dir to your ndk folder.

Just add
ndk.dir=
with you ndk folder in local.properties

Can't build Tango c examples

I downloading the Tango C examples and opened point-cloud-jni-example in Android Studio. I have ndk installed and added ndk.dir=E:\Android\sdk\ndk-bundle to my local.properties file. Gradle syncs without errors, but when I run, I get this error:
Error:Execution failed for task ':app:ndkBuild'.
A problem occurred starting process 'command 'E:\Android\sdk\ndk-bundle/ndk-build''
I get the same error with motion-tracking-jni-example and hello-tango-jni-example and I assume the others as well.
What am I doing wrong?
build.gradle (app):
apply plugin: 'com.android.application'
android {
compileSdkVersion 19
buildToolsVersion "21.1.2"
defaultConfig {
applicationId "com.projecttango.experiments.nativepointcloud"
minSdkVersion 19
targetSdkVersion 19
}
sourceSets.main {
jniLibs.srcDir 'src/main/libs'
jni.srcDirs = [];
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
}
}
}
tasks.withType(JavaCompile) {
compileTask -> compileTask.dependsOn ndkBuild
}
task ndkBuild(type: Exec) {
Properties properties = new Properties()
properties.load(project.rootProject.file('local.properties').newDataInputStream())
def ndkbuild = properties.getProperty('ndk.dir', null)+"/ndk-build"
commandLine ndkbuild, '-C', file('src/main/jni').absolutePath
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
}
build.gradle (Project):
// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
repositories {
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:1.1.0'
}
}
allprojects {
repositories {
jcenter()
}
}
My system:
Windows 8.1 64 bit
Android Studio 1.3 (AI-141.2117773)
NDK r10e extracted to E:\Android\sdk\ndk-bundle
Device: Project Tango Tablet with Schur core

You need to append '.cmd' to the ndkbuild command. By that, I mean that the line
def ndkbuild = properties.getProperty('ndk.dir', null)+"/ndk-build"
should read
def ndkbuild = properties.getProperty('ndk.dir', null)+"/ndk-build.cmd"
It was no fault of your own, I noticed the same issue when I went to compile on my Surface.

Unable to build GStreamer tutorials using Android Studio

I am trying to build the tutorials that are bundled with gstreamer-sdk-android-arm-debug-2013.6. The Android.mk file in the src/jni directory (tutorial 1 project) references environment variables such as GSTREAMER_SDK_ROOT. From what I have read, Android Studio does not use/pass environment variables to the build scripts. Is there a best practice for modifying makefiles and for defining/retrieving the key/value pairs required by the build scripts?

Ok, I have a working solution. You CAN pass environment variables to ndk-build (or any other process spawned by gradle Exec). In my case, I wanted to set these for both the clean and build tasks. This is is done using tasks.withType(Exec). The environment parameter is set here for all Exec tasks.
For GSTREAMER_SDK_ROOT, I added an entry to local.properties:
gst.dir=/Users/svenyonson/sdk/gstreamer-sdk-android-arm-debug-2013.6
For PATH, I used the default for the spawned process and added in what I needed.
Here is a working version of build.gradle:
apply plugin: 'com.android.application'
android {
compileSdkVersion 19
buildToolsVersion "20.0.0"
defaultConfig {
applicationId "com.gst_sdk_tutorials.tutorial_1"
minSdkVersion 19
targetSdkVersion 19
}
sourceSets.main {
jni.srcDirs = []
jniLibs.srcDir 'src/main/libs'
java.srcDirs += 'src/main/jni/src'
}
tasks.withType(Exec) {
def localProperties = new Properties()
localProperties.load(project.rootProject.file('local.properties').newDataInputStream())
def gstDir = localProperties.getProperty('gst.dir')
environment = [:]
environment['PATH'] = System.getenv("PATH")+ ":/usr/local/bin"
environment['GSTREAMER_SDK_ROOT'] = gstDir
}
task buildNative(type: Exec, description: 'Compile JNI source via NDK') {
def ndkDir = project.plugins.findPlugin('com.android.application').getNdkFolder()
commandLine "$ndkDir/ndk-build",
'-C', file('src/main/jni').absolutePath,
'-j', Runtime.runtime.availableProcessors(),
'all',
'NDK_DEBUG=1',
'V=1',
'APP_PLATFORM=android-19'
}
task cleanNative(type: Exec, description: 'Clean JNI object files') {
def ndkDir = project.plugins.findPlugin('com.android.application').getNdkFolder()
commandLine "$ndkDir/ndk-build",
'-C', file('src/main/jni').absolutePath,
'clean'
}
clean.dependsOn 'cleanNative'
tasks.withType(JavaCompile) {
compileTask -> compileTask.dependsOn buildNative
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
}
}
}
The project now builds and runs. The only other things you will need to do is add ndk.dir to local.properties:
sdk.dir=/Users/svenyonson/sdk/android-sdk
ndk.dir=/Users/svenyonson/sdk/android-ndk-r9d
gst.dir=/Users/svenyonson/sdk/gstreamer-sdk-android-arm-debug-2013.6
One more thing: These examples will not build using android-ndk-r10d. Be sure to use android-ndk-r9d.

Android Studio NDK Build trouble Error:Execution failed for task ':app:buildNative'

Hi. I'm in Android Studio NDK Build trouble. I've not used native library. just java classes for library use and JNI c or header files.
So I've confused how to write gradle file for my project(saskin library ; I'm studying it).
Please help me~!
Error message
Error:Execution failed for task ':app:buildNative'.
A problem occurred starting process 'command 'C:\NDK/ndk-build''
build.gradle
apply plugin: 'com.android.application'
android {
compileSdkVersion 8
buildToolsVersion "21.1.1"
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
}
}
sourceSets {
main {
jni.srcDirs = []
//jniLibs.srcDir 'src/main/libs'
}
}
defaultConfig {
applicationId "com.sasken.player"
minSdkVersion 8
targetSdkVersion 8
ndk {
moduleName "equalizer"
}
}
// call regular ndk-build(.cmd) script from app directory
task ndkBuild(type: Exec) {
commandLine 'ndk-build', '-C', file('src/main/jni').absolutePath
}
tasks.withType(JavaCompile) {
compileTask -> compileTask.dependsOn ndkBuild
}
}
dependencies {
}

since you're using Windows, you should call ndk-build.cmd instead of ndk-build, from your ndkBuild task.
To make your gradle file work on windows and unix-compatible systems you can modify your task this way:
import org.apache.tools.ant.taskdefs.condition.Os
// call regular ndk-build(.cmd) script from app directory
task ndkBuild(type: Exec) {
if (Os.isFamily(Os.FAMILY_WINDOWS)) {
commandLine 'ndk-build.cmd', '-C', file('src/main').absolutePath
} else {
commandLine 'ndk-build', '-C', file('src/main').absolutePath
}
}
Also, as you're using ndk-build directly, the ndk will generate your libraries inside the libs folder, so you should uncomment jniLibs.srcDir 'src/main/libs' inside your gradle file, in order for your generated libs to be taken in account.