Nexus 7 tablet: NFC - how to align 2 devices to make a transaction

The Nexus 7 tablet offers the feature of NFC  (and Google Beam) to transfer files with other NFC enabled device by putting them together.

In one of my previous posts, I included a photo of the inner side of the Nexus 7's back cover, it shows the antenna for NFC,  it is located in the upper center part.

Because the size of the Nexus 7 tablet and the position and size of the NFC antenna, and these physical settings in other devices used to NFC (Google Beam) with Nexus 7, I found that it would make user try several times to find the correct position for the two devices to do a successful NFC transaction.

I used HTC One X (quad-core model) in my test. I tried several times to find the proper position to align these 2 devices back to back to make a successful NFC connection.

Since HTC One X is uni-body in design, it could not be open easily to find the position of its NFC antenna, so I do not know where the antenna is located on the back cover of HTC One.

Fortunately if there is a successful NFC connection, HTC One X would make a sound, so it did not take me several tries to find that out, I just slide the HTC One X on the back of Nexus 7, and quickly found out the antenna of HTC One X is fixed in the lower part of the phone back cover.

So you can imagine how it would look like when the two devices align well to make a successful NFC connection. The smaller device HTC One X sticks out of the upper edge of Nexus 7, and they need to be in the position of back to back. In the position of side-by-side, NFC connection would not happen.

Other interesting finding is that both of the devices need to be active, their screen would not be in lock state or in power off state.

Now if you would like to use NFC on your Nexus 7 tablet with other NFC enabled device,
please remember the NFC antenna of Nexus 7 is located in the upper-center of its back cover.,
and try to align other device with Nexus 7 at that part of the back cover.

Nexus 7 tablet: show surface updates,Pointer location

When I placed one of my phone on top of the Nexus 7 tablet, the camera of the phone can generate touch events when it touch the tablet screen. It happened to be that on the tablet, it is on the Developer options screen, and the camera of the phone turned on option of "Pointer location" and "Show surface updates". The coordinates and other values of the touching point would be displayed at the top of the screen near the row of notification bar, and the motion event trace would be drawn on the screen, the values are dX dY, (or X, Y when the touching point is moving), Xv, Yv, Prs, Size, the values of Xv and Yv look like to be speed or velocity, Size is the value of area value of the touching point, not sure the meaning of Prs, is it pressure or the perimeter value?

 If "Show surface updates" is turned on, the screen would flash with different color.

The problems is if I turned on "Show surface updates" and clicked on the Home soft key, the home screen will keep blinking , indicating there are some surface updating events happening, though I did not touch the screen surface. I checked this on my phone, there is not such problem.

Android: play with the samples

Android SDK includes a set of samples, allowing developers to check available features and learn how to use the APIs. Android plugin for Eclipse IDE makes it very easy for developers to play with the samples.

After installing the Eclipse, Android SDK manager, and ADT plugin for Eclipse,
you may first run the SDK manager to update all versions of Android SDK, 3rd party SDKs,
and you will find the samples under the folder where you installed Android SDK, for example, on my laptop, it is C:\android-sdk\samples. From there you can choose the sample of one SDK version.

1. Start up Eclipse IDE if it is not running.
2. From the menu, File-> New->Project -> Android -> Android Sample Project
3. In the dialogue window, choose "Next".
4. From the "Build Target" window, choose the version of the SDK from which the samples are included.
5. In the next window, please choose the sample you would like to check.

Now the sample project you select would be created in the workspace.

If you would like to load all of the samples coming with the SDK,
In the 2nd step above, you need to go the other way
2. From the menu, File -> New -> Project -> Android -> Android Project from Existing Code
3. Choose "Next"
4. From the dialogue window, choose the directory where the samples are located, for example  C:\android-sdk\samples\android-16
5. Selected the projects you'd like to look at
6. If you'd like to, check "Copy projects into workspace".
7. Click "Finish".

Then the projects you selected would be loaded into Eclipse.

From here and on, you can dive into the source codes.
After building each project, you can install it to the device to play with it.

PS: I am using Eclipse 4.2 Juno 64bit for Windows.

Android: set up app development environment

Android platform is more popular now that 5 years ago when it was just launched with the developer preview version. Now devices with Android framework are activated tons per day. It attracted millions of developers to develop applications for this platform.

It is recommended from official Google Android site, Eclipse IDE (version for Java developer and above) is to be used, though other IDEs can also be used.

The follow lists official links for setting up the development environment

Installing Eclipse
http://wiki.eclipse.org/Eclipse/Installation
The latest version as of July 2012 is 4.2 Juno.
Please note that Java SDK needs to be installed first before you install Eclipse,
it is available at Oracle (Sun) Java SDK download site

http://www.oracle.com/technetwork/indexes/downloads/index.html

Installing Android SDK
http://developer.android.com/sdk/installing/index.html
On Windows machine, you just need to run the installer.

Adding platform and packages
 http://developer.android.com/sdk/installing/adding-packages.html

Adding ADT plugin to Eclipse
http://developer.android.com/sdk/installing/installing-adt.html

Tools for Android application development
http://developer.android.com/tools/index.html

You may also consider install other tools, plugins, such revision controls,
into Eclipse
Subclipse - http://subclipse.tigris.org/update_1.8.x

Training guide for newcomers
http://developer.android.com/training/basics/firstapp/index.html

How to publish your APIs in an Android SDK addon

If you happen to have a set of APIs and would like to package them into an Android addon to share with other developers, please first build a library project and compile all the source codes into java classes, and if possible use javadoc or other documentation tools to create the API documents. But before that, please make sure you have added enough info to the java source codes, so that this info would be extracted by the java documentation tool to create the API documents.

Now you can create a folder, called my.xyz.sdk. Inside of it, please create sub-folder "libs", "docs" to hold the jar file and API documents respectively. And if you also want to share the sample code, you may create a sub-folder "samples", and put the samples in it.

Inside of folder my.xyz.sdk, please create 3 text files, i.e., hardware.ini, manifest.ini and source.properties.

In hardware.ini, you can define display density and virtual machine heap size. For example

# Custom hardware options for the add-on.
# Properties defined here impact all AVD targetting this add-on.
# Each skin can also override those values with its own hardware.ini file.
hw.lcd.density=240
vm.heapSize=24

In manifest.ini, you can set parameters for the SDK addon, such as name, vendor, api level, version, library name, jar file and description. For example,

# SDK Add-on Manifest
# File encoding is UTF-8
name=My XYZ SDK
vendor=My XYZ
# version of the Android platform on which this add-on is built.
api=10
# revision of the add-on
revision=1
# list of libraries, separated by a semi-colon.
libraries=MyXYZSDK;

MyXYZSDK=MyXYZSDK.jar; MyXYZ library

In the source.properties file, you can specify package description, addon name, package revision, addon vendor, and Android API level. For example,

### Android Tool: Source of this archive.
Pkg.Desc=My XYZ SDK - API Level 1.0.1
Addon.Name=MY XYZ addon Jul 23, 2012
Pkg.Revision=1.0.1
Addon.Vendor=My XYZ
AndroidVersion.ApiLevel=10

Now all files in the MyXYZSDK folder and its sub-folders are ready.
Please proceed to use any compression tool, such Zip, 7zip, to zip the folder and create a zip file, named it as MyXYZSDK.zip.

If you want developers to download and install your SDK addon with Android SDK Manager, then  
after the zip MyXYZSDK.zip is created, please open a command window, either on Windows machine or Linux, and use OpenSSL tool, sha1 or md5, to get the checksum value for the zip file,
 copy and paste the checksum value into the repository.xml file.

In the repository.xml, you can define some parameters for the addon. The following is a sample.

?xml version="1.0" encoding="UTF-8"?>
<sdk:sdk-addon
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:sdk="http://schemas.android.com/sdk/android/addon/1">
    <sdk:add-on>
        <sdk:name>MY XYZ SDK</sdk:name>
        <sdk:api-level>10</sdk:api-level>
        <sdk:vendor>My XYZ</sdk:vendor>
        <sdk:revision>1.0.1</sdk:revision>
        <sdk:description>My XYZ SDK addon, API 10, revision 1.0.1</sdk:description>
        <sdk:desc-url>http://myxyz.com</sdk:desc-url>
        <sdk:uses-license ref="androidaddonlicense" />
        <sdk:archives>
            <sdk:archive os="any">
                <sdk:size>27230698</sdk:size>
                <sdk:checksum type="sha1">2d9ca1f0034d431b7f5096d3b4dd3574ac848d46</sdk:checksum>
                <sdk:url>http://dl.myxyz.com/sdk/download/MyXYZSDK.zip</sdk:url>
            </sdk:archive>
        </sdk:archives>
        <sdk:libs>
        </sdk:libs>
    </sdk:add-on>
    <sdk:license type="text" id="androidaddonlicense">SOFTWARE DEVELOPERS TECHNOLOGY LICENSE AGREEMENT ..."></sdk:license>
</sdk:sdk-addon>

Now if you would like to test the addon SDK downloading, you need to revise the repository.xml, and change the sdh_url value pointing to the url on your testing server.

Please put both repository.xml and MyXYZSDK.zip into the folder on your testing server. And on your local computer, create a testing xml file to list your SDK addon site, for example

<?xml version="1.0"?>

<sdk:sdk-addons-list xmlns:sdk="http://schemas.android.com/sdk/android/addons-list/1"> <sdk:addon-site> 

<sdk:url> https://dl-ssl.google.com/android/repository/addon.xml </sdk:url>

 <sdk:name>Google Inc.</sdk:name>

</sdk:addon-site> 

<sdk:addon-site> 

<sdk:url>http://alpha-test.myxyz.com/sdk/addon.xml</sdk:url>

<sdk:name>MyXYZ</sdk:name>

</sdk:addon-site> 

</sdk:sdk-addons-list>
and put it in a folder "sdktest".

From the command prompt on your local computer, set the path of SDK_TEST_BASE_URL to the full path of the "sdktest" folder, then run Android SDK Manager by starting "android". Now you can test the downloading of the MyXYZSDK.

If there are some errors, you may go to the steps mentioned above to repeat them again.

After all is well, you can move the MyXYZSDK.zip, repository.xml to your production server.

And also do not forget to contact Google to include the repository url into their SDK addon list,
so that developers would be able to see it in the list of Android SDK addon.

Nexus 7: how to flash the device

After unlocking the boot loader of the device, owner can flash the device with customized roms, or when you screwed up with the customized rom, you can still try to flash the device with the official rom available from Google's download site.

Assuming you now have the rom to be used to flash the device, and have android tools, such adb, fastboot, on your computer, you may follow the steps below to flash the rom onto the device.

Before flashing the device, please make sure to back up all of your data files on your device. It is always safe to keep back up of your data.

1. Open a DOS command window (if you are using Windows machine) or a command prompt ( on Unix machine).
2. Connect your device to your PC with the USB cable.
3. Please make sure there is enough battery left on your device.
4. In the command prompt, run adb command, i.e., adb devices,  to check if the device is recognized.
5. If the device is recognized, then run adb command, i.e., , adb reboot bootloader,  to get the device into boot loader mode.
6. In the command prompt, run command, fastboot flash zip the-full-path-to-the-rom-zip-file .
7. In the command prompt, you will see the computer is sending the file to the device, and files are extracted out from the zip, and deployed.
8. Wait until the flash process is finished.
9. In the command prompt, run command to reboot the device if it is not rebooted automatically:
adb reboot, or fastboot reboot.
10. In case, the flashing process fails in the middle, it would remind you to flash again immediately. Please run the command, fastboot flash zip the-full-path-to-the-rom-zip-file, again.
11. In some cases,  the 2nd and following runs of command above also fails, you will need to run the other flashing command, such as, fastboot oem rebootRUU, first, then run the flash zip command above.

After the device is flashed with the new rom, it would go through the setting up processes.

You may also consider locking it up again: fastboot oem lock

Windows 8: tools needed to write app

Windows 8 apps would run on Windows 8 platform, no matter the hardware it a Desktop, laptop, netbook, tablet or phone. Apps developed on Windows 8 would be able to run on a range of devices running Windows 8 operating system.

In previous post, I talked about downloading Windows 8 Preview Release, and install the OS into hardware either as a host OS or as a virtual machine running on a host.

After installing Windows 8, developers would need to download and install other tools.
The IDE (Integrated Development Environment) for Windows 8 app development is the Visual Studio Express 2012

Other tools such as Blend for Visual Studio, Windows 8 SDK, project templates, Design assets, Windows 8 Advertisement SDK, Window 8 Live SDK, and Metro Style app samples are also available for download.

Please go to http://msdn.microsoft.com/en-us/windows/apps/br229516.aspx to download these tools.


In case you would be developing apps for users of languages other than English,
you can download the multilingual app toolkit for Visual Studio, and use it to localize the apps.
 


Enjoy developing apps for Windows 8.

Nexus 7: Taking off the back cover and peek inside of it

The Nexus 7 has a white polymer (PC + ABS, recycling category 7) back cover, it is very tightly fixed, originally I felt it would be not easy to take the back over off, and it turned out very easy to pull it off. I just used my finger nails along the side of the back cover and force it slowly to open.

The big chunk part is the battery, it uses about 1/3 of the space available to fit in the parts. Above the big battery, there is a hole on the board, it could be used to fit in a back camera.

On the back cover, there are several finger prints left on the copper foil, it should be from the worker who had worked on this unit.

ANTs for GPS, WiFi and NFC are also fixed on to the upper part of the back cover, all of them are from ACON. on the lower part of the back cover, there seems to be parts related geo-sensors.

I have not got chance to take a look at the arrangements of parts in Asus' other 7" tablet, but
the arrangement of the parts for Nexus 7 might be similar to those.

Nexus 7: want to choose a touch sound? no way !

Nexus 7 is more of a hot topic now among mobile and tablet users.
One of the feature of it is to set sound for notification, and turn on or off the sound for touching event and screen lock event.

For notification sound, user can choose from a list sounds, or choose silent. I heard of the feature of setting sounds for different events, such as email update, phone call, text message, and social media update, but I did not find it out how to do it. Maybe I need to download something.

At first glance, in the Settings-> Sound, I saw options of "Default notification", "Touch sounds", "Screen lock sound", I assumed there are options for me to choose different sound for touch event and screen lock event.
but it turned out that these 2 settings are on-off option, unlike "Default notification" settings, Nexus 7 is not offering a list of sounds allowing user to choose, though the menu option item for touch event is "Touch sounds". User just is offered the option to turn on or off the sound.

I am wondering why Nexus 7 is not offering the same options of "Default notification" settings to "Touch sounds" settings and "Screen lock sound" settings.

Nexus 7: form "factorS"

People usually say Nexus 7 has a 7" form factor, which means the size of the screen.
I'd rather use the phrase "form factor" to describe the geometrical properties of the device, such as length, width and height when it is laid down on the surface.

These parameters are listed on the official page at Google page at http://www.google.com/nexus/#/7/specs, which read " SIZE 198.5 x 120 x 10.45mm". So the value of length is 198.5mm, width is 120mm, height is 10.45mm. I measured the screen size with the ruler, the length is about 150mm, the width is about 94 mm.


Just assume the width of the top frame is the same as that of the bottom frame, which look like it is, then the width of the top and bottom frame would be 24.25mm, and the width of the left and right frame would be 13mm. I realized that maybe the design is trying to mimic the ratio and size of real books, just like those eBook readers.
 
But considering the soft keys are used and there is only one not-so-good-front-face camera, the width of the top frame and bottom frame could be just as the same of the left frame and right frame, like that on Galaxy 10 tablet, then to me the tablet would look more prettier, and surely more lighter.


Now come to the height. While putting it side by side with iPad2, Galaxy 10 4G LTE, and HTC One X, it is easy to notice the Nexus 7 stands out. Some people may say that Nexus 7 packs some powerful hardware, e.g., quad core CPU, GPU, and sensors, into its belly, and more space is needed to solve technical issues, such as size of battery, cooling, etc., but just look at the HTC One X, it also has similar hardware, and all those pieces are packed into the phone.


What I want to say here is that, the Nexus 7 is kind of rush in design, it could have had a better design. But considering the time to show the device at Google IO, and its cheap price tag, it can be understood why it is it is now on the market. 


Is the design just a copy of the Asus other 7" android tablet?

Nexus 7 tablet: dark theme preloaded wallpapers

Google Nexus 7tablet (8GB version) comes with a black frame around the display. That may be the reason why all of the preloaded wallpapers are in the spectrum of darker range.

First, in the category of "Live wallpaper", there are "Bubbles", "Holo Spiral", "Phase Beam".
All of the them have dark color.

Then in the category of "Wallpaper", there are 10 wallpaper, 7 of them have dark color, 3 of them have light color.

Thanks to the option of "Gallery", which allows users choose their own photos as wallpaper.

By the way, if you pay attention to the menu on the wallpaper selection view,
 the option for live wallpaper is "Live Wallpaper", the mixed case is different from other views.

And because the tablet is running Jelly Bean and using soft keys at the bottom, it makes user wondering why the frame at the bottom is so wide. The width would have been set the same as that of the frames on the left and right side. I have not open the case yet, maybe at the bottom, the space is used to pack in the hardware.

Please check the link below about display issue of Nexus 7,
http://www.zdnet.com/google-nexus-7-bright-image-compression-blamed-on-oem-incompetence-7000001450/ 
darker image would do well with the display, but brighter image would not.
Is this the reason why there are fewer brighter preloaded wallpaper ?

Windows 8: Metro Style Applications

Windows 8 allows user to run metro style applications. In the Start screen, applications are arranged as titles instead of icons. The data on the tile could be set as "alive", which means it could be updated periodically to reflect current state of the data belongs to application. Data can either be pushed to the live tile or ask for update from the service.

When the Metro style application is started up, it would use one window which fills the entire screen to host views in various layout formats. It can interact with user via traditional ways such as mouse, keyboard, but also the intuitive ways such as touch and pen. Communications between metro style applications are allowed through contracts. Data would be shared among metro style applications having contracts.

Developers can develop applications or application components in programming languages such as C#, VB.Net, C++, C++Extension, HTML5, Java Script. Application components developed in one programming language can be used in application developed in other programming language, this interoperability will encourage developers to develop reuse the components and save the development time for other applications in the future.

Setup Window 8 VM on Oracle VirtualBox

Window 8 Preview is available for download. Users interested in taking at look at the new OS from Microsoft may install it as a virtual machine on Oracle Virtual Box。

The preview download can be found at http://msdn.microsoft.com/en-us/windows/apps/br229512.aspx.
You may either burn the iso image to a DVD or save it on USB drive.

Detail instructions of installing Windows 8 on Oracle Virtual Box could be found at  http://windows8installation.com/?s=network+adapter&x=0&y=0 . 
 Please pay attention to the steps to choose network adapter.

When installing Windows 8 on Oracle Virtual Box, please check the System Requirements and set the corresponding configuration parameters correctly for the virtual machine.

I did not experience any issue when I went through the installing process,
but it took a little bit longer for my host laptop to install and create the VM.
Now it runs perfectly on top of the host machine. 

Please note that, if your PC has multiple cores,
you may consider choose a certain numbers of cores for the Windows 8 virtual machine. This could be done in the settings of the virtual machine. But remember please do not assign all cores and RAM to the virtual machine, otherwise you may run into problem with the host machine, such as slow response or freeze. You can always change this settings every time before you start up the virtual machine.
 

Nexus 7: which preloaded apps can be used offline (without network connection)

On the given away Nexus 7 tablet from Google I/O 2012, there are 28 preloaded apps (including the Google Wallet, it got installed later in an update). Here is the list of apps that can be used by user when there is not network connection.

1. Calculator
2. Clock
3. Downloads
4. Earth (some features would need network connection)
5. Gallery (some features, such as sharing or sending, would need network connection)
6. Gmail （Gmail could work offline allowing user to check downloaded email)
7. Latitude (It would ask user to log into Google account, but user can skip it to view map)
8. Local (partially, user can view map, but not search)
9. Map (partially, user can view map, but some other features would not work without network connection)
10.Navigation (partially)
11. People (partially)
12.Play Music (partially, for files on device)
13. Play Books (for downloaded books, but would need a Google account)
14. Play Magazines (for downloaded magazines, but need a Google account)

So part of those preloaded apps would not fully work if there is not network connections,
these reloaded apps are heavily rely on network connection for user to use,
which means the data user would like to use is totally online, either provided by Google or other content and/or service providers.

But this model of Nexus 7 is Wi-Fi only version.
For users on the way without Wi-Fi hotspot to use,
this tablet is not very useful.

Even though there would public Wi-Fi network allowing users to get online,
users would have concerns of privacy, because the types of data and services they would be used via those preloaded apps.

It would be much better if Google is going to provide a model that can use wireless data services provide by carriers/operators.

Nexus 7: which preloaded apps need your gooogle account login

As it is mentioned in a previous post, the setting up process of the Google Nexus 7 tablet would need user's email account (Google gmail account). Looks like there is no way to by pass that step, but you may remove that account later after finishing the setting up process. However, some of the preloaded apps on the tablet definitely need user's
email account and need user to log into those accounts.

Here is the list of these apps:
1. Current
2. Email
3. Gmail
4. Google
5. G+
6. Latitude
7. Map (My places)
8. Messager
9. People (recommended)
10. Play Books
11. Play Magzines
12. Play Movies & TV
13. Play Store (will need account login when downloading apps)
14. Talk
15. Wallet
16. YouTube(if user want to upload or play playlist)
So totally 16 out of 28 preloaded apps or some features of these apps  need user to log into user's Google account.

Nexus 7 Tablet: The Brain and The Belley

Nexus 7 tablet has the Android 4.1 as part of the brain, it is also called Jelly Bean. Besides the Jelly Bean, there is a set of services provided by Google, such as Google Now, Google Play, Voice Search, Google map, Google Plus, Chrome, YouTube, etc..

Most of these services are bound to user's Google account, and need network connection, which means, without Google account or network connection, these services would not be available. At the core is the Linux kernel 3.1.10. If you are curious, you may peek into the file system of the device.

The belly of the device is set of pieces of hardware, including the CPU, GPU, RAM, storage, camera, radio, the display, the battery, sensors, etc..

The CPU of Nexus 7 tablet is a quad core, working together with a 12-core Nvidia GPU and 1GB RAM. The Nexus 7 has a 7  inch display with 1280x800 resolution. The version of the tablet I got from IO has 8GB storage. It is said that the 16Wh Li-polymer battery can give 9.5 hours of backup.
The front-facing 1.2-megapixel camera can be used for video chat or taking low resolution photos, there is not rear camera.

Nexus 7 tablet how to: unlocking bootloader

If you are a developer, you would most probably like to unlock bootloader of Nexus 7 tablet, or even root it.

Here I list the steps to unlock the bootloader.

It is assumed that you already have the Android SDK installed on your computer,
the tools, such adb, fastboot, are available. Please note that by unlocking the bootloader of your
Nexus 7 tablet, your data would be lost. Please back up your data before unlocking your tablet.

1. Make sure adb could see the Nexus 7 tablet when you connect it to PC using the included cable in the box. From the DOS command prompt, you can use the command "adb devices" to check if it is available. If it is not available on the output list of adb command, please follow the instructions to install drivers to the computer.

2. Boot the tablet into bootloader mode. You can run the command "adb reboot rebootloader" in the DOS command prompt. Please check the text at the left lower corner. If it says "Lock State - Unlocked", the bootloader of your Nexus 7 tablet has already been unlocked; otherwise, it would say "Lock State - Locked".

3. On your computer, please run "fastboot oem unlock" in the DOS prompt.

4. On your Nexus 7 tablet, please read the warnings on the screen and use the volume button on the right side of the tablet to navigate and choose "Yes" or "No", and use the power button to select and proceed.

5. On your computer, in the DOS prompt where you ran the "fastboot oem unlock" command, you will see  the progress.

6. After it is done, please use the volume button on the right side of your Nexus 7 tablet to restart the device, or run "fastboot reboot" in the DOS prompt on your computer.

7. On your tablet, you will notice that the tablet is rebooting, and at the bottom of the screen,
you will see there is a lock and it is unlock, indicating your Nexus 7 tablet is unlocked.

8. Now you may proceed to the setting process.

Nexus 7 tablet How to: add or remove account

Beside the account you added in the device configuration process, you may want to add other accounts for the services Google provides, and you may also want to remove one account.

To add a new account,
1. Click on home button at the bottom of the screen
2. Click the application icon in the center of the row above the home button
3. Click on "Settings"
4. Scroll to "ACCOUNTS"
5. Click on "Add account"
6. Follow the instructions on the screen to add a new account

To remove an account from the Nexus 7 tablet,
1. Follow step 1 to step 4
2. Click on the account you want to remove
3. Click on the menu at the upper-right corner of the screen
4. Choose "Remove account" to remove it.
Please note that when you remove an account,
all data linked to this account may be deleted,
and may not be recovered.