Debug Android Apps on chromebook using ADB

Background

Chromebook now supports Android Apps to be run. At Google I/O 2016, it was announced that Android apps would be available to run on supported Chromebooks via the Google Play Store, which will result in having two app stores in Chrome OS. ARC's native code approach was abandoned, instead using unmodified copy of Android's framework running in a container. Android apps run in floating windows now. You can also see google playstore in your chrome once you enable it in settings -

In this post we will see how we can run ADB and side load android apps.

 Debug Android Apps on chromebook using ADB

First make sure you your chromebook is in developer mode and and you have also enabled developer options in android settings. All of this was already shown in my last post -

•  How to enable developer mode on a Chromebook

Now from developer options turn on ADB debugging.

Now go to your shell again and execute following commands -

• sudo crossystem dev_boot_signed_only=0
• sudo /usr/libexec/debugd/helpers/dev_features_rootfs_verification
• sudo reboot

This should reboot your chromebook . This will setup set up developer features and enable disk-write access for the firewall settings changes.

 On reboot execute following command in shell -

• sudo /usr/libexec/debugd/helpers/dev_features_ssh

This will configure secure shell for you.

 And you are done. Now just note down the ip of your chromebook (you can execute ifconfig in shell to know)

and from your development machine type connect adb. Eg if your chromebook ip is 192.168.1.6 you will type -

• adb connect 192.168.1.2:22

You can type following command to verify it is connected -

• adb devices

 Now you can execute all adb commands including install to install your dev apk builds.

And you should see it get installed on your chromebook -

Related Links

• How to enable developer mode on a Chromebook (OSFG) 
• Optimizing Apps for Chromebooks

How to enable developer mode on a Chromebook

Before you Start

Caution: Modifications you make to the system are not supported by Google, may cause hardware, software or security issues and may void warranty.

Couple of things to note -

1. You will have to turn of verified boot which mean you or anyone can install a custom (non google verified) image.
2. This will give you access to root console/shell.
3. All your local data will be erased. Your device will be essentially reset. All your cloud data will still be present.

So to sum up your device will be less secure. Do this on your own risk.

NOTE : This article in intended only for developers and advanced users.

If you are concerned about anything mentioned above this would be a good point to turn back.

How to enable developer mode on a Chromebook

1. Press and hold 'Esc' and refresh key (the button with a circular arrow - which is in place of your F3). Holding these buttons press your power key.
   
   
   
2. You should now see a recovery mode screen with an exclamation icon. Press 'Ctrl' + 'D'. You will see screen displaying press Enter to turn of OS verification.
   
   
   
   
   
   
   
3. Press Enter. You will see a transition screen displaying message of transition to developer mode.
   
   
   
4. After some time your device should reboot and start in developer mode. At the end you should see your normal setup screen with language, keyboard layout etc.
   

How would you test that you are in developer mode?

• First of all you should be able to access shell (console). Press Ctrl + Alt + T. Then in opened console type shell. You should be getting access to your normal linux command line.

•  You can also check your chrome setting. You should be able to see all new advanced setting available. You can also see Android internal setting here. You can very well go ahead tab on Build number in About devices and turn on Android developer mode to access developer options. You can use this to turn on USB debugging and adb.

That's it you are now in developer mode. You have root access and can do more cool stuff. But remember  - With great power comes great responsibility :)

NOTE :  If Ctrl + D is not working you  can press Refresh+Power to boot in developer mode with ctrl+D or hit space and wipe clean.

Related Links

• How to take a screenshot on your Chromebook
•  Poking around your Chrome OS Device  
• My Chromebook Pixel will not let me enable Developer Mode

How to take a screenshot on your Chromebook

Background

A Chromebook is a laptop running the Linux-based Chrome OS as its operating system. Yup you read it right it is Linux based. It used Linux kernel underneath. The devices are designed to be used primarily while connected to the Internet, with most applications and data residing in "the cloud".

Chromebooks ship with Google Chrome OS, an operating system that uses the Linux kernel and the Google Chrome web-browser with an integrated media-player.

Your Chromebook is different from your personal laptops and Desktops. There are two essential things to consider before you go for a chromebook

1. Chrome OS : This is the OS that runs on your chromebook. You need to get familiar with it. Chrome OS is an operating system designed by Google and based upon the Linux kernel. Google announced the project in July 2009, conceiving it as an operating system in which both applications and user data reside in the cloud: hence Chrome OS primarily runs web applications. (Wiki)
2. Cloud computing : This is a major deal breaker here. Chromebook essentially is a cloud computing device. You access your data stored in cloud and signout when done. Most if your data is in cloud. So even if you lose your chromebook your data is safe.

Without these two your chromebook is essentially a browser!

Following video posted by google which sums up what chromebook really is.

There are tons of different things associated with chromebook from it's keyboard layout, its file directories all the way to the apps you run on it. Will get into those details in perhaps upcoming posts but in this post we will see how to take a screenshot on your chromebook.

How to take a screenshot on your Chromebook

• To take screenshot of entire screen you need to press ‘Ctrl’ and ‘Window Switcher’ keys together.
  
  
  
• To get a part of the screen you need to press ‘Ctrl’ , ‘Shift’  and ‘Window Switcher’ keys together.

Once you do that you should see a notification saying "Screenshot taken".

Screenshots will be available under Downloads directory of your chromebook.


 As I mentioned earlier keyboard layout of your chromebook is different than your traditional laptop. For eg. you don't have a capslock or a delete button. Instead if capslock you would see a search button. Anyway to understand keyboard shortcuts you can press

• Ctrl + Alt + ?

And you should see a keyboard layout. When you press on

• Ctrl or
• Search or
• alt or
• their combinations

you should see their corresponding key shortcuts. For rg when you press Ctrl while on that layout you can see all shortcuts starting with Ctrl. Notice the screenshot shortcut we saw above -

Related Links

• Chrome OS Wiki

How to Uninstall Apps from Android Wear

Background

In last post we had some discussion on how to add a wearable module to your existing android app. In this post we will see how to uninstall app from your your android wear. For this you need to have Android wear app installed on your phone -

• https://play.google.com/store/apps/details?id=com.google.android.wearable.app&hl=en

 Lets see now how we can remove the app.

How to Uninstall Apps from Android Wear

• Make sure you are connected to your wearable device from your wearable app installed on your phone

• Next click on settings icon.

• Under Device Setting click on your device connected

• Next click on watch storage and you should see your app listed there.

• You cannot directly uninstall app from here. Rather you cannot uninstall app from wear device and still keep it on your mobile (Unless you use adb command to remove it :)). Anyway uninstall the app from your device. Go to your connected app and click on Resync apps. Your app on wearable device should automatically get removed.

Related Links

•  Setting up Firebase Cloud Messaging (FCM) in Android application(OSFG)
• How to send Firebase Cloud Messaging (FCM) notification from server to client(OSFG) 
• Adding and packaging wear module to your existing Android application (OSFG)

Adding and packaging wear module to your existing Android application

Background

Smart watches are slowing making their way into the market. They are quite expensive today but hoping prices will slash down with increase of technology. Anyway this post is aimed to add a wearable module to your existing Android app. This post expects you

1. Have an existing Android application code
2. Have it setup in latest Android Studio

So now that we have our prerequisites in place lets see how we can do this.

Step 1 : Adding a wearable  module to your Android application

If you have have your android application code opened in studio you simply need to 

1. Open module settings
2. Create on + (plus) button and select "Android Wear Module" .
3. Next give your module name (NOTE : Make sure your wear module bundle id is same as your main android app bundle id)
4. Next select activity
5. Give your activity/layout name
6. Click Finish

 Once you do this you should see a new module in your project with the name you provided during configuration. It will have its own set of java files, resource files, icons, manifest, build.gradle file etc.

You can go ahead and code your logic into this. This will run on your wearable device.

Step 2 : Packaging Wearable Apps

The way wearable app is distributed is by packaging it inside your handheld application (apk gets bundled inside) and when this app is installed on your phone/handheld device the wearable apk will get pushed to your wearable device.

To properly package a wearable module -

1. Include all the permissions declared in the manifest file of the wearable app module in the manifest file of the handheld app module. For example, if you specify the VIBRATE permission for the wearable app, you must also add that permission to the handheld app.
2. Ensure that both the wearable and handheld app modules have the same package name and version number.
3. Declare a Gradle dependency in the handheld app's build.gradle file that points to the wearable app module: 
   
   Eg.
   
   

   dependencies {
       compile fileTree(dir: 'libs', include: ['*.jar'])
       testCompile 'junit:junit:4.12'
       compile 'com.android.support:appcompat-v7:23.4.0'
       compile 'com.android.support:support-v4:23.4.0'
       compile 'com.google.android.gms:play-services:9.0.0'
       wearApp project(':flashlightwear')
   }
   

   
   
4. Click Build > Generate Signed APK.

How it works

• Your android mobile/handheld application and your wearable application (apk) should be signed using same certificate (key). 
• They must also have same package name and version number.
• When you generate a release build if your handheld application your wearable apk will get bundled in your handheld apk.
• When you install your handheld app on your mobile which is paired to your wearable device (eg smart watch) then wearable apk bundled within will be automatically pushed and installed on the wearable device.
• You cannot take a call on which ones to keep or not keep. If you have an app installed on your mobile device and it has a wear module it will be installed on your wearable device. You cannot uninstall it unless you remove the app from your phone.

You should see a notification on your wear device that app is installed.

I have added wear module to a flashlight app that I had developer sometime back just to learn this stuff. You can check it out. Its available on playstore -

• https://play.google.com/store/apps/details?id=com.osfg.flashlight

NOTES:

1. Ensure that both the wearable and handheld app modules have the same package name and version number.
2. Include all the permissions declared in the manifest file of the wearable app module in the manifest file of the handheld app module. 
3.  Your android mobile/handheld application and your wearable application (apk) should be signed using same certificate (key).
4. wearable apk gets automatically bundled with your handheld module and gets pushed to your wearable device once installed on handled device.

Related Links

•  Setting up Firebase Cloud Messaging (FCM) in Android application(OSFG)
• How to send Firebase Cloud Messaging (FCM) notification from server to client(OSFG) 
• Create a New Module
• Packaging Wearable Apps 
• How to Uninstall Apps from Android Wear(OSFG)