April 17, 2017

Learning Appium Desktop: How to Connect To Your Android Device Using the Android SDK, the Android Command Line Tools, and the Android Debug Bridge (adb)

This is Part 2 of 6. Care to go back to the beginning? Tune in tomorrow to see the next part!

Last blog post, we went over how to get the Appium Server running on a Macbook, through the new Appium Desktop product.

With this post, we are going to cover:
  • Installing the Android SDK (Software Development Kit) on our Macbook through installing Android Studio
  • How to use some command line tools such as adb 
  • How to connect your Android devices wirelessly to your system

What is the Android SDK?

From Webotopia: "A software development kit that enables developers to create applications for the Android platform. The Android SDK includes sample projects with source code, development tools, an emulator, and required libraries to build Android applications. Applications are written using the Java programming language and run on Dalvik, a custom virtual machine designed for embedded use which runs on top of a Linux kernel".

What Does the Android SDK Consist Of?

From Developer.Android.Com:
"The Android SDK is composed of multiple packages that are required for app development. This page lists the most important command line tools that are available, organized by the packages in which they're delivered.

"You can install and update each package using Android Studio's SDK Manager or the sdkmanager command line tool. All of the packages are downloaded into your Android SDK directory".

Android.com really wants you to use their Android Studio, which comes with an IDE built on top of IntelliJ IDEA, with the Android SDK and easy ways to download emulators built in. 

For this proof-of-concept, we are going to try to use the Command Line tools and steer away from extraneous graphic-user-interfaces besides Android Desktop. 

Here are some of the packages we will be using, taken from https://developer.android.com/studio/command-line/index.html#tools-build

Android SDK ToolsLocated in: android_sdk/tools/bin/
"See also: SDK Tools release notes

"This package is platform independent and required no matter which Android platform you are developing on.

"If you just need these tools because you're not using Android Studio, you can download the SDK Tools here.
  • "avdmanager: Allows you to create and manage Android Virtual Devices (AVDs) from the command line.
  • "sdkmanager: Allows you to view, install, update, and uninstall packages for the Android SDK".

Android SDK Platform Tools: Located in: android_sdk/platform-tools/
"See also: SDK Platform Tools release notes

"These tools are updated for every new version of the Android platform to support new features (and sometimes more often to fix or improve the tools), and each update is backward compatible with older platform versions.

"In addition to downloading from the SDK Manager, you can download the SDK Platform Tools here.
  • "adb: Android Debug Bridge (adb) is a versatile tool that lets you manage the state of an emulator instance or Android-powered device. You can also use it to install an APK on a device".
Android Emulator: Located in: android_sdk/emulator/
"See also: Android Emulator release notes

"This package is required to use the Android Emulator. It includes the following:
  • "emulator: A QEMU-based device-emulation tool that you can use to debug and test your applications in an actual Android run-time environment".

How to Install the Android SDK?

If we wanted to, we could scroll all the way down to the bottom of the Android Studio page where it says:
"Get just the command line tools: If you do not need Android Studio, you can download the basic Android command line tools below. You can use the included sdkmanager to download other SDK packages. [...] These tools are included in Android Studio".

Instead, let's Download Android Studio

These tools will be all downloaded together. All we would need to do after is set up our bash_profile to have the variable $ANDROID_HOME point to the location of the Android SDK, their tools, and their platform-tools.

... Why am I setting this up on a Macbook? Because of the Linux system built into Macbooks.

By getting used to the Mac Terminal, it can get me used to various SysAdmin type tools I will need to know if I ever want to get into DevOps (Dev + Ops == System Admin + Dev + QA). It's just practice using the command line.

How Do I Install Android Studio?

Once I Install Android Studio, How Do I Find the Path to the Android SDK?

  • Open up Android Studio
  • Go to File -> Project Structure.
  • See what the path is. It should be something like: /Users/tmaher/Library/Android/sdk

How Do I Set Up The Terminal to Use These Tools?

The Mac Terminal is running an instance of "Bash", the "Bourne Again" shell. We want to add the /Android/sdk/platform-tools and /Android/sdktools that were placed in your Mac Library by Android Studio accessible everywhere, not just in the particular directory where the tools lie.

To set it up, much like we set up JAVA_HOME, we are going to set up that location as ANDROID_HOME for your bash profile.

Note: Want a quick way to Change Directory to your Home Directory via the Command Line? cd ~

a) Open up a Mac Terminal
b) Go into the text editor called "nano", opening up your .bash_profile

  • nano ~/.bash_profile
c) Add the following:
  • export ANDROID_HOME=~/Library/Android/sdk
  • export PATH=$PATH:$ANDROID_HOME/tools:$ANDROID_HOME/platform-tools

... That will set the variable, "$ANDROID_HOME" as the Library directory off of your home directory, in the Android/sdk subfolder. Once that variable is set, we can use it to also point to the /tools and the /platform-tools subdirectory. 

d) Save and Close nano by entering:
  • CNTRL + X (Note: ^ is a shortcut for CNTRL button). 
  • Y to answer "Yes" to saving the changes.
  • [ENTER] to save changes.

e) Check that it worked:
  • source ~/.bash_profile 
  • echo $ANDROID_HOME
If you had really wanted to be tricky, you could have entered the following commands on the Command Line:
  • echo "export ANDROID_HOME=~/Library/Android/sdk" >> ~/.bash_profile
  • echo "export PATH=$PATH:$ANDROID_HOME/tools:$ANDROID_HOME/platform-tools" >> ~/.bash_profile

What is the Android Debug Bridge?

From Android Developer’s Android Debug Bridge page: https://developer.android.com/studio/command-line/adb.html
“Android Debug Bridge (adb) is a versatile command-line tool that lets you communicate with a device (an emulator or a connected Android device). The adb command facilitates a variety of device actions, such as installing and debugging apps, and it provides access to a Unix shell that you can use to run a variety of commands on a device. It is a client-server program that includes three components:
  • “A client, which sends commands. The client runs on your development machine. You can invoke a client from a command-line terminal by issuing an adb command.
  • “A daemon (adbd), which runs commands on a device. The daemon runs as a background process on each device.
  • “A server, which manages communication between the client and the daemon. The server runs as a background process on your development machine.

How Do Set Up the USB Connection From My Android Device to My Computer?

1) Enable USB Debugging, Unhide Developer Options:
  • Go to your Android phone
  • Go to Settings and scroll down almost to the bottom setting
  • Select About Device. On Build Number, tap seven times. This will turn on Developer Mode.
  • Go back to the main Settings screen. There is a new option called Developer Options.
... Once you see this option on screen, if you connect your computer to your device, you can communicate via USB!

2) Attach a USB Cable from your Android mobile device to your computer.
  • You may see a popup message on your Android device asking for permission to start the connection. Press “OK” to grant it. 
  • Once this is drivers are installed on your system, and the RSA KEY is added to your mobile phone. 

3) Confirm that it worked: See the adb devices connected.

Type the following in your Mac Terminal to see if your device is registered: adb devices

For the Samsung Galaxy S7 Edge I am using, after setting up Developer Options, and connecting it via USB, after typing: adb devices

 $ adb devices  
 List of devices attached  
 412327b5 device  

If we had a few emulators attached (which we will do later), we might see:
 $ adb devices  
 List of devices attached  
 emulator-5554 device  
 emulator-5555 device  

Remember these names! We will need that name to communicated with the various real Android devices and the emulators.

Playing Around With ADB

Want more information about the devices? List the long form, by: adb android -l

“In response, adb prints this status information for each device:
  • “Serial number: A string created by adb to uniquely identify the device by its port number. Here's an example serial number: emulator-5554
  • “State: The connection state of the device can be one of the following:
  • offline: The device is not connected to adb or is not responding.
  • device: The device is now connected to the adb server. Note that this state does not imply that the Android system is fully booted and operational because the device connects to adb while the system is still booting. However, after boot-up, this is the normal operational state of an device.
  • no device: There is no device connected.
  • “Description: If you include the -l option, the devices command tells you what the device is. This information is helpful when you have multiple devices connected so that you can tell them apart”.

How to Install Software to a Device or Emulator

Installing an app is simple, once you have it connected. Let’s say there is an Android app, an *.apk, on the Macbook Desktop called “helloWorld.apk” that we want to install on an emulator:

 $ adb devices  
 List of devices attached  
 emulator-5554 device  
 emulator-5555 device  
 $ adb -s emulator-5555 install ~/Desktop/helloWorld.apk  

Remember these Linux shortcuts:

~ points to your Home Directory, therefore cd ~ takes you home.

Install ~/Downloads/helloWorld.apk would install from a file you downloaded onto your Mac.

... There are so many features you can do with adb on the command line. See https://developer.android.com/studio/command-line/adb.html to see them all! You can:

  • Copy files and directories to and from a device pushing and pulling files from your device to your computer and back.
  • Install applications, granting run time permissions, allowing test packages, installing it on the SD card.
  • Backup all data on the device choosing to back up .apk files or not, include system apps or not.
  • Restore all data from a file.
  • Print a bugreport to a zip file.
  • You can start, kill, or reconnect adb.

Other features we may need....

Issue ADB shell commands

“You can use the shell command to issue device commands through adb, with or without entering the adb remote shell on the device. To issue a single command without entering a remote shell, use the shell command”.

Call the Package Manager (pm) via Shell

Within an adb shell, you can issue commands with the package manager (pm) tool to perform actions and queries on application packages installed on the device. While in a shell, the syntax is:

pm command

You can also issue a package manager command directly from adb without entering a remote shell. For example:

adb shell pm uninstall com.example.MyApp

Take a screenshot from the ADB Shell

The screencap command is a shell utility for taking a screenshot of a device display. While in a shell, the syntax is:

screencap filename

To use the screencap from the command line, type the following:

adb shell screencap /sdcard/screen.png

Here's an example screenshot session, using the adb shell to capture the screenshot and the pull command to download the file from the device:

$ adb shell

shell@ $ screencap /sdcard/screen.png
shell@ $ exit

$ adb pull /sdcard/screen.png

Record a video from the ADB Shell

The screenrecord command is a shell utility for recording the display of devices running Android 4.4 (API level 19) and higher. The utility records screen activity to an MPEG-4 file.

Note: Audio is not recorded with the video file.

A developer can use this file to create promotional or training videos. While in a shell, the syntax is:

screenrecord [options] filename

To use screenrecord from the command line, type the following:

adb shell screenrecord /sdcard/demo.mp4

Stop the screen recording by pressing Control + C, otherwise the recording stops automatically at three minutes or the time limit set by --time-limit.

To begin recording your device screen, run the screenrecord command to record the video. Then, run the pull command to download the video from the device to the host computer. Here's an example recording session:

$ adb shell

shell@ $ screenrecord --verbose /sdcard/demo.mp4

(press Control + C to stop)

shell@ $ exit
$ adb pull /sdcard/demo.mp4

The screenrecord utility can record at any supported resolution and bit rate you request, while retaining the aspect ratio of the device display. The utility records at the native display resolution and orientation by default, with a maximum length of three minutes.

There are some known limitations of the screenrecord utility that you should be aware of when using it:

Some devices might not be able to record at their native display resolution. If you encounter problems with screen recording, try using a lower screen resolution.

List all packages on the device from the ADB Shell:

adb shell pm list packages

Next, we will connect our physical Android devices wirelessly to our computer! See you tomorrow! 

Happy Testing!

-T.J. Maher
Twitter | LinkedIn | GitHub

// Sr. QA Engineer, Software Engineer in Test, Software Tester since 1996.
// Contributing Writer for TechBeacon.
// "Looking to move away from manual QA? Follow Adventures in Automation on Facebook!"

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