This post aims at providing a brief guide on using NDK (Native Development Kit) to build a shared library for an Android application.
Be noted that this post will not teach you how to develop a whole JNI supported Android application, the outcome of the following procedure will only lead you to generate a shared library (*.so file) which you can use for your android application.
And if you want to really use this generated library, you will have to change some function formats according to your project, modification part will be covered of course.
Be noted that this post will not teach you how to develop a whole JNI supported Android application, the outcome of the following procedure will only lead you to generate a shared library (*.so file) which you can use for your android application.
And if you want to really use this generated library, you will have to change some function formats according to your project, modification part will be covered of course.
Using Android Studio 2.2 and higher, you can use the NDK to compile C and C code into a native library and package it into your APK using Gradle, the IDE's integrated build system. Your Java code can then call functions in your native library through the Java Native Interface (JNI) framework. May 07, 2017. Visual Studio Build doesnt skip projects that are mark skipped for build and deploy 1 Solution VS2017 hosted agents' Android NDK is out of date 0 Solution Xamarin.Android build definition template can't build Xamarin.Forms project 0 Solution. All parameters to ndk-build are passed directly to the underlying GNU make command that runs the NDK build scripts. Combine ndk-build and options in the form ndk-build. For example: $ ndk-build clean The following options are available: clean Remove any previously generated binaries. Note: On Mac OS X, running ndk-build clean with a.
Download Essentials
Android NDK is a must.
Set Up NDK Environment
As we need to use ndk-build command to build the C/C++ code for Android applications running under the ARM architecture. First we need to let the system to know where to find ndk-build.
Open a terminal and type as follows (noted that you need you change the ndk path according to your download and location):
Open a terminal and type as follows (noted that you need you change the ndk path according to your download and location):
Then edit your .bashrc file.
If the setting is wrong, you may see the result “ndk-build: command not found”.
If you get “Android NDK: Could not find application project directory!”, then everything seems work well.
If you get “Android NDK: Could not find application project directory!”, then everything seems work well.
Prepare Code
Now, if you work under a Android project, create a new folder “jni” under your project folder, we are going to place all the native related code under this folder; inside of “jni” folder, create another folder “include”, we are to place all the native (we call C/C++ code under java: native code, get use to it, there’s no why, I also feels weird to this name, but native is indeed easier to pronounce when comparing to C and C plus plus.) header file under this folder.
Create a file named “Android.mk” under “jni” folder, this file will provide necessary information to ndk-build tool, and also create a file named HelloNative.c under “jni” folder, this file will be the C/C++ source code; create “HelloNative.h” file under “/jni/include/“ folder, this include file is the interface header of Java and C/C++.
Source tree structure will be something like:
Create a file named “Android.mk” under “jni” folder, this file will provide necessary information to ndk-build tool, and also create a file named HelloNative.c under “jni” folder, this file will be the C/C++ source code; create “HelloNative.h” file under “/jni/include/“ folder, this include file is the interface header of Java and C/C++.
Source tree structure will be something like:
“…” represents other Android related files or folders. It’s ok if you are not working under a real Android project, that means “…” part can be NULL.
Prepare HelloNative.h file:
Prepare HelloNative.c file:
Prepare Android.mk file:
Now, we have all the necessary source for ndk to build.
Commands
Under the working directory:
Output
After you typed the command, “obj” folder and “libs” folder will be generated under your work directory.
Inside of the “libs” folder, there will be a few sub-folders corresponding to different hardware architectures, for example “arm64-v8a”, “armeabi-v7a”, “x86”, “x86_64” or “mips”.
Each of the above sub-folder will contain a file named “libhellojni.so”. This is the target dynamic library we want.
Inside of the “libs” folder, there will be a few sub-folders corresponding to different hardware architectures, for example “arm64-v8a”, “armeabi-v7a”, “x86”, “x86_64” or “mips”.
Each of the above sub-folder will contain a file named “libhellojni.so”. This is the target dynamic library we want.
How to use the library
Add Application.mk for an Android application.
Android.mk tells the ndk compiler how to build a specific native module (shared library), application.mk tells the compiler which module to use for your application and some characters of the modules.
Edit Application.mk under jni folder:
Android.mk tells the ndk compiler how to build a specific native module (shared library), application.mk tells the compiler which module to use for your application and some characters of the modules.
Edit Application.mk under jni folder:
After add this file, only armeabi-v7a version library will be generated.
And also you need a Android java activity, edit file JNIActivity.java file:
Then generate .apk file by any way you like.
Reference
This post mainly takes here as reference.
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License
The content of this blog itself is licensed under the Creative Commons Attribution 4.0 International License.
The containing source code (if applicable) and the source code used to format and display that content is licensed under the Apache License 2.0.
Copyright [2016] [yeephycho]
Licensed under the Apache License, Version 2.0 (the “License”);
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
Apache License 2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an “AS IS” BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
express or implied. See the License for the specific language
governing permissions and limitations under the License.
Environment setup¶
Ndk Build Android Studio
Linux¶
GroundSdk Android has been tested on Ubuntu 18.04.You should adapt some commands to your Linux distribution.
Download the latest Android Studio, and unpack it to
/opt
Note
GroundSdk has been successfully tested with Android Studio 3.4
Follow the installation instructions for Linux, which include downloading Android SDK components.
Download Android NDK Revision 17c for Linux, and unpack it to
/opt
Note
GroundSdk will not build with newer NDK revisions. That’s why youshould not install NDK from Android Studio SDK Manager.
Note that you can still have several NDK revisions installed on your computer,you just have to reference the 17c revision as described below.
Permanently set environment variables (this will modify your
~/.profile
file) with the following commandsNote
You should use the Android Studio embedded JDK as shown in this example.
Autocad 2016 crack and keygen win7. You can find the default Android SDK path in Android Studiosettings, in Appearance & Behavior > System Settings > Android SDK
Reload the
.profile
file to take your changes into accountInstall the required tools
Install the Repo tool
- Download it from Google APIs
- Put it in a directory that is included in your path
- Make it executable with
chmoda+xrepo
Configure git with your real name and email address
You’re ready to clone the GroundSdk workspace.
Mac OS¶
GroundSdk Android has been tested on macOS 10.14.4 Mojave. Yandere simulator free mac.
Download the latest Android Studio
Note
GroundSdk has been successfully tested with Android Studio 3.4
Follow the installation instructions for Mac, which include downloading Android SDK components.
Download Android NDK Revision 17c for Mac, and copy the unpacked
android-ndk-r17c
directory to /usr/local
Note
GroundSdk will not build with newer NDK revisions. That’s why youshould not install NDK from Android Studio SDK Manager.
Note that you can still have several NDK revisions installed on your computer,you just have to reference the 17c revision as described below.
Permanently set environment variables (this will modify your
~/.bash_profile
file) with the following commandsNote
You should use the Android Studio embedded JDK as shown in this example.
You can find the default Android SDK path in Android Studiosettings, in Appearance & Behavior > System Settings > Android SDK
Reload the
.bash_profile
file to take your changes into accountAndroid Studio Ndk Location
Install Homebrew
Install the required tools using Homebrew
Configure git with your real name and email address
Clone the GroundSdk workspace¶
Create your working directory
Initialize Repo in your working directory
Note
You can learn how to use Repo on the Repo command reference page
Download the GroundSdk source tree
Build GroundSdk¶
Type the following command to build GroundSdk for Android, including the Demo application
Note
Android Studio Ndk Tutorial
You can run
./build.sh--help
to learn more about the building optionsRun GroundSdk Demo¶
- Launch Android Studio (on Linux, run
/opt/android-studio/bin/studio.sh
) - Click on “Open an existing Android Studio project”
- Select the
groundsdk/groundsdk-android
directory and click OK / Open - Connect an Android device to your computer
- Run
groundsdkdemo
application
Connect to your drone¶
- Switch on your drone
- Open wifi settings on your Android device
- Select your drone’s wifi access point (e.g. ANAFI-xxxxxxx)
- Open GroundSdk Demo app
- Select the DRONES tab
- Your drone should appear in the list, select it
- Click on CONNECT