Android NDK: Beginner's Guide

Go to http://cygwin.com/install.html and download the Cygwin setup program suitable for your environment. Once downloaded, execute it.

In the installation window, click on Next and then Install from Internet.

Follow the installation wizard screens. Consider selecting a download site from where Cygwin packages are downloaded in your country.

Then, when proposed, include the Devel, Make, Shells, and bash packages:

Follow the installation wizard until the end. This may take some time depending on your Internet connection.

Download Oracle JDK 7 from the Oracle website at http://www.oracle.com/technetwork/java/javase/downloads/index.html (or JDK 8, although it is not officially supported at the time this book is written). Launch and follow the installation wizard until the end.

Download Ant from its website at http://ant.apache.org/bindownload.cgi and unzip its binary package in the directory of your choice (for example, C:\Ant).

After installation, define JDK, Cygwin, and Ant locations in environment variables. To do so, open Windows Control Panel and go to the System panel (or right-click on the Computer item in the Windows Start menu and select Properties).

Then, go to Advanced system settings. The System Properties window appears. Finally, select the Advanced tab and click on the Environment Variables button.

In the Environment Variables window, inside the System variables list, add:

Prepend %CYGWIN_HOME%\bin;%JAVA_HOME%\bin;%ANT_HOME%\bin;, all separated by a semicolon, at the beginning of your PATH environment variable.

Finally, launch a Cygwin terminal. Your profile files get created on the first launch. Check the make version to ensure Cygwin works:

make –version

You will see the following output:

Ensure JDK is properly installed by running Java and checking its version. Check carefully to make sure the version number corresponds to the newly installed JDK:

java –version

You will see the following output on the screen:

From a classic Windows terminal, check the Ant version to make sure it is properly working:

ant -version

You will see the following on the terminal:

Open your web browser and download the Android Studio bundle from http://developer.android.com/sdk/index.html.

Run the downloaded program and follow the installation wizard. When requested, install all Android components.

Then, choose the installation directories for Android Studio and the Android SDK (for example, C:\Android\android-studio and C:\Android\sdk).

Launch Android Studio to ensure it is properly working. If Android Studio proposes to import settings from a previous installation, select your preferred option and click on OK.

The Android Studio welcome screen should then appear. Close it.

Go to http://developer.android.com/tools/sdk/ndk/index.html and download the Android NDK (not SDK!) suitable for your environment. Extract the archive inside the directory of your choice (for example, C:\Android\ndk).

To easily access Android utilities from the command line, let's declare the Android SDK and NDK as environment variables. From now on, we will refer to these directories as $ANDROID_SDK and $ANDROID_NDK.

Open the Environment Variables system window, as we did previously. Inside the System variables list, add the following:

Prepend %ANDROID_SDK%\tools;%ANDROID_SDK%\platform-tools;%ANDROID_NDK%;, all separated by a semicolon, at the beginning of your PATH environment variable.

All Windows environment variables should be imported automatically by Cygwin when launched. Open a Cygwin terminal and list the Android devices connected to your computer (even if none are currently) with adb to check whether SDK is working. No error should appear:

adb devices

Check the ndk-build version to ensure that NDK is working. If everything works, the Make version should appear:

ndk-build -version

Open Android SDK Manager, located in the ADB bundle directory's root.

In the opened window, click on New to select all the packages and then click on the Install packages... button. Accept the licenses in the popup that appears and start the installation of Android development packages by clicking on the Install button.

After a few long minutes, all packages are downloaded and a confirmation message indicating that the Android SDK manager has been updated appears.

Validate and close the manager.

A JDK is preinstalled on OS X 10.6 Snow Leopard and below. On these systems, Apple's JDK is in version 6. Since this version is deprecated, it is advised to install an up-to-date JDK 7 (or JDK 8, although it is not officially supported at the time this book is written).

On the other hand, OS X 10.7 Lion and above does not have a default JDK installed. Installing the JDK 7 is thus mandatory.

To do so, download Oracle JDK 7 from the Oracle website at http://www.oracle.com/technetwork/java/javase/downloads/index.html. Launch the DMG and follow the installation wizard until the end.

Check the Java version to ensure that the JDK is properly installed.

java -version

All Developer Tools are included in the XCode installation package (Version 5, at the time this book is written). XCode is provided on the AppStore for free. Starting from OS X 10.9, the Developer Tools package can be installed separately from a terminal prompt with the following command:

xcode-select --install

Then, from the popup window that appears, select Install.

To build native code with the Android NDK, whether XCode or the single Developer Tools package is installed, we need Make. Open a terminal prompt and check the Make version to ensure that it correctly works:

make –version

On OS X 10.9 and later, Ant must be installed manually. Download Ant from its website at http://ant.apache.org/bindownload.cgi and unzip its binary package in the directory of your choice (for example, /Developer/Ant).

Then, create or edit the file ~/.profile and make Ant available on the system path by appending the following:

export ANT_HOME="/Developer/Ant"
export PATH=${ANT_HOME}/bin:${PATH}

Log out from your current session and log in again (or restart your computer) and check whether Ant is correctly installed by checking its version from the command line:

ant –version

Open your web browser and download the Android Studio bundle from http://developer.android.com/sdk/index.html.

Run the downloaded DMG file. In the window that appears, drag the Android Studio icon into Applications and wait for Android Studio to be fully copied on the system.

Run Android Studio from Launchpad.

If an error Unable to find a valid JVM appears (because Android Studio cannot find a suitable JRE when launched), you can run Android Studio from the command line as follows (using the appropriate JDK path):

export STUDIO_JDK=/Library/Java/JavaVirtualMachines/jdk1.7.0_71.jdk
open /Applications/Android\ Studio.apps

If Android Studio proposes to import settings from a previous installation, select your preferred option and click on OK.

In the next Setup Wizard screen that appears, select the Standard installation type and continue the installation.

Complete the installation until the Android Studio welcome screen appears. Then, close Android Studio.

Go to http://developer.android.com/tools/sdk/ndk/index.html and download the Android NDK (not SDK!) archive suitable for your environment. Extract it inside the directory of your choice (for example, ~/Library/Android/ndk).

To easily access Android utilities from the command line, let's declare the Android SDK and NDK as environment variables. From now on, we will refer to these directories as $ANDROID_SDK and $ANDROID_NDK. Assuming you use the default Bash command-line shell, create or edit .profile (which is a hidden file!) in your home directory and append the following instructions (adapt paths according to your installation):

export ANDROID_SDK="~/Library/Android/sdk"
export ANDROID_NDK="~/Library/Android/ndk"
export PATH="${ANDROID_SDK}/tools:${ANDROID_SDK}/platform-tools:${ANDROID_NDK}:${PATH}"

Log out from your current session and log in again (or restart your computer). List the Android devices connected to your computer (even if none currently are) with adb to check whether Android SDK is working. No error should appear:

adb devices

Check the ndk-build version to ensure that NDK is working. If everything works, the Make version should appear:

ndk-build -version

Open a terminal and start the Android SDK manager with the following command:

android

In the opened window, click on New to select all the packages and then click on the Install packages... button. Accept the licenses in the popup that appears and start the installation of all Android packages by clicking on the Install button.

After a few long minutes, all packages are downloaded and a confirmation message indicating that the Android SDK manager has been updated appears.

Validate and close the manager.

From Command Prompt, check whether Glibc (the GNU C standard library) 2.7 or later, usually shipped with Linux systems by default, is installed:

ldd -–version

Make is also required to build native code. Install it from the build-essential package (requires administrative privilege):

sudo apt-get install build-essential

Run the following command to ensure Make is correctly installed, in which case its version is displayed:

make –version

On 64-bit Linux systems, install the 32-bit libraries compatibility package, as Android SDK has binaries compiled for 32 bits only. To do so on Ubuntu 13.04 and earlier, simply install the ia32-libs package:

sudo apt-get install ia32-libs

On Ubuntu 13.10 64 bits and later, this package has been removed. So, install the required packages manually:

sudo apt-get install lib32ncurses5 lib32stdc++6 zlib1g:i386 libc6-i386

Install Java OpenJDK 7 (or JDK 8, although it is not officially supported at the time this book is written). Oracle JDK is also fine:

sudo apt-get install openjdk-7-jdk

Ensure JDK is properly installed by running Java and checking its version:

java –version

Install Ant with the following command (requires administrative privilege):

sudo apt-get install ant

Check whether Ant is properly working:

ant -version

Open your web browser and download the Android Studio bundle from http://developer.android.com/sdk/index.html. Extract the downloaded archive in the directory of your choice (for example, ~/Android/Android-studio).

Run the Android Studio script bin/studio.sh. If Android Studio proposes to import settings from a previous installation, select your preferred option and click on OK.

In the next Setup Wizard screen that appears, select a Standard installation type and continue installation.

Complete installation until the Android Studio welcome screen. Then, close Android Studio.

Go to http://developer.android.com/tools/sdk/ndk/index.html and download the Android NDK (not SDK!) archive suitable for your environment. Extract it inside the directory of your choice (for example, ~/Android/Ndk).

To easily access Android utilities from the command line, let's declare the Android SDK and NDK as environment variables. From now on, we will refer to these directories as $ANDROID_SDK and $ANDROID_NDK. Edit your .profile file (beware since this is a hidden file!) in your home directory and add the following variables at the end (adapt their path according to your installation directories):

export ANDROID_SDK="~/Android/Sdk"
export ANDROID_NDK="~/Android/Ndk"
export PATH="${ANDROID_SDK}/tools:${ANDROID_SDK}/platform-tools:${ANDROID_NDK}:${PATH}"

Log out from your current session and log in again (or restart your computer). List the Android devices connected to your computer (even if none currently are) with adb to check whether Android SDK is working. No error should appear:

adb devices

Check the ndk-build version to ensure that NDK is working. If everything works, the Make version should appear:

ndk-build -version

Open a terminal and start the Android SDK manager with the following command:

android

In the opened window, click on New to select all the packages, and then click on the Install packages... button. Accept the licenses in the popup that appears and start the installation of all Android package by clicking on the Install button.

After a few long minutes, all packages are downloaded and a confirmation message indicating that the Android SDK manager has been updated appears.

Validate and close the manager.

Go to http://www.eclipse.org/downloads/ and download Eclipse for Java developers. Extract the downloaded archive in the directory of your choice (for example, C:\Android\eclipse on Windows, ~/ Android/Eclipse on Linux, and ~/Library/Android/eclipse on Mac OS X).

Then, run Eclipse. If Eclipse asks for a workspace (which contains Eclipse settings and projects) when starting up, define the directory of your choice or leave the default settings and then click on OK.

When Eclipse has finished loading, close the welcome page. The following window should appear:

Go to Help | Install New Software…. Enter https://dl-ssl.google.com/android/eclipse in the Work with: field and validate. After a few seconds, a Developer Tools plugin appears. Select it and click on the Next button.

Follow the wizard and accept conditions when asked. On the last wizard page, click on Finish to install ADT. A warning may appear indicating that the plugin content is unsigned. Ignore it and click on OK. When finished, restart Eclipse as requested.

Go back to Help | Install New Software…. Open the Work with combobox and select the item containing the Eclipse version name (here, Luna). Then, check the Show only software applicable to target environment option. Find Programming Languages in the plugin tree and unfold it. Finally, check all C/C++ plugins and click on Next.

Follow the wizard and accept conditions when asked. On the last wizard page, click on Finish. Wait until the installation is complete and restart Eclipse.

Go to Windows | Preferences... (Eclipse | Preferences... on Mac OS X) and then select Android on the left tree. If everything is fine, the SDK Location should be filled with the Android SDK path.

Then, on the same window, go to Android | NDK. The NDK Location field should be empty. Fill it with the Android NDK path and validate. If the path is wrong, Eclipse complains that the directory is not valid.

Open Android SDK Manager from a terminal by running the following command:

android

Go to Tools | Manage AVDs.... Alternatively, click on the dedicated Android Virtual Device Manager button in the main toolbar of Eclipse.

Then, click on the New button to create a new Android emulator instance. Fill the form with the following information and click on OK:

The newly created virtual device now appears in the Android Virtual Device Manager list. Select it and click on Start....

The Launch Options window appears. Tweak the display size depending on your screen size if needed and then click on Launch. The emulator starts up and after some time, your virtual device is loaded:

By default, the emulator SD card is read only. Although this is optional, you can set it in write mode by issuing the following command from a prompt:

adb shell
su
mount -o rw,remount rootfs /
chmod 777 /mnt/sdcard
exit

Configure your device driver on your OS if applicable:

If your mobile device runs Android 4.2 or later, from the application list screen, go to Settings | About phone and tap several times on Build Number at the end of the list. After some efforts, Developer options will magically appear in your application list screen.

On Android 4.1 devices and earlier, Developer options should be visible by default.

Still on your device, from the application list screen, go to Settings | Developer options and enable Debugging and Stay awake.

Plug your device into your computer using a data connection cable. Beware! Some cables are charge-only cables and will not work for development! Depending on your device manufacturer, it may appear as a USB disk.

On Android 4.2.2 devices and later, a dialog Allow USB debugging? appears on the phone screen. Select Always allow from this computer to permanently allow debugging and then click on OK.

Open Command Prompt and execute the following:

adb devices

On Linux, if ????????? appears instead of your device name (which is likely), then adb does not have proper access rights. A solution might be to restart adb as root (at your own risk!):

sudo $ANDROID_SDK/platform-tools/adb kill-server
sudo $ANDROID_SDK/platform-tools/adb devices

Another solution to find your Vendor ID and Product ID may be needed. Vendor ID is a fixed value for each manufacturer that can be found on the Android developer website at http://developer.android.com/tools/device.html (for example, HTC is 0bb4). The device's Product ID can be found using the result of the lsusb command in which we look for the Vendor ID (for example, here 0c87 is HTC Desire product ID):

lsusb | grep 0bb4

Then, with root privilege, create a file /etc/udev/rules.d/51-android.rules with your Vendor ID and Product ID and change file rights to 644:

sudo sh -c 'echo SUBSYSTEM==\"usb\", SYSFS{idVendor}==\"<Your Vendor ID>\", ATTRS{idProduct}=\"<Your Product ID>\", GROUP=\"plugdev\", MODE=\"0666\" > /etc/udev/rules.d/52-android.rules'
sudo chmod 644 /etc/udev/rules.d/52-android.rules

Finally, restart the udev service and adb:

sudo service udev restart
adb kill-server
adb devices

Launch Eclipse and open the DDMS perspective (Window | Open Perspective | Other...). If working properly, your phone should be listed in the Devices view.