There’s something to be said about great ideas and this is just one of those. If you own a digital camera, then you know exactly what it’s like to have a big memory card that can take hundreds of photos before you download to your computer. But you always get people asking you for copies of the photos, or wanting you to upload them to your computer or Facebook so they can see them. And guess what, you never have a card reader when you need one; and you can never get your photos off your card. We’ve all experienced this frustration haven’t we?

Well, someone came up with the brilliant idea of building Wifi into an SD card, which means that any SD camera can now hook up to a WiFi network, allowing you to copy photos right off the card to your computer, or even up to the Web. It’s called Eye-Fi and here’s a short video about it:

To tell you the truth, I didn’t know that such a device existed before I came across it today, and it’s definitely up there as one of the interesting gadgets I’ve seen this year. It’s a device that was invented to fit a need, and anyone with a digital camera can relate to the need. Who knows, it might work well as a Christmas present for someone you know.

photo credit: Josh Russell

There are four building blocks to an Android application:

* Activity
* Intent Receiver
* Service
* Content Provider

Not every application needs to have all four, but your application will be written with some combination of these.

Once you have decided what components you need for your application, you should list them in a file called AndroidManifest.xml. This is an XML file where you declare the components of your application and what their capabilities and requirements are. See the Android manifest file documentation for complete details.

Activity
Activities are the most common of the four Android building blocks. An activity is usually a single screen in your application. Each activity is implemented as a single class that extends the Activity base class. Your class will display a user interface composed of Views and respond to events. Most applications consist of multiple screens. For example, a text messaging application might have one screen that shows a list of contacts to send messages to, a second screen to write the message to the chosen contact, and other screens to review old messages or change settings. Each of these screens would be implemented as an activity. Moving to another screen is accomplished by a starting a new activity. In some cases an activity may return a value to the previous activity — for example an activity that lets the user pick a photo would return the chosen photo to the caller.

When a new screen opens, the previous screen is paused and put onto a history stack. The user can navigate backward through previously opened screens in the history. Screens can also choose to be removed from the history stack when it would be inappropriate for them to remain. Android retains history stacks for each application launched from the home screen.

Intent and Intent Filters
Android uses a special class called an Intent to move from screen to screen. An intent describes what an application wants done. The two most important parts of the intent data structure are the action and the data to act upon. Typical values for action are MAIN (the front door of the activity), VIEW, PICK, EDIT, etc. The data is expressed as a URI. For example, to view contact information for a person, you would create an intent with the VIEW action and the data set to a URI representing that person.

There is a related class called an IntentFilter. While an intent is effectively a request to do something, an intent filter is a description of what intents an activity (or intent receiver, see below) is capable of handling. An activity that is able to display contact information for a person would publish an IntentFilter that said that it knows how to handle the action VIEW when applied to data representing a person. Activities publish their IntentFilters in the AndroidManifest.xml file.

Navigating from screen to screen is accomplished by resolving intents. To navigate forward, an activity calls startActivity(myIntent). The system then looks at the intent filters for all installed applications and picks the activity whose intent filters best matches myIntent. The new activity is informed of the intent, which causes it to be launched. The process of resolving intents happens at run time when startActivity is called, which offers two key benefits:

* Activities can reuse functionality from other components simply by making a request in the form of an Intent
* Activities can be replaced at any time by a new Activity with an equivalent IntentFilter

Intent Receiver
You can use an IntentReceiver when you want code in your application to execute in reaction to an external event, for example, when the phone rings, or when the data network is available, or when it’s midnight. Intent receivers do not display a UI, although they may use the NotificationManager to alert the user if something interesting has happened. Intent receivers are registered in AndroidManifest.xml, but you can also register them from code using Context.registerReceiver(). Your application does not have to be running for its intent receivers to be called; the system will start your application, if necessary, when an intent receiver is triggered. Applications can also send their own intent broadcasts to others with Context.broadcastIntent().

Service
A Service is code that is long-lived and runs without a UI. A good example of this is a media player playing songs from a play list. In a media player application, there would probably be one or more activities that allow the user to choose songs and start playing them. However, the music playback itself should not be handled by an activity because the user will expect the music to keep playing even after navigating to a new screen. In this case, the media player activity could start a service using Context.startService() to to run in the background to keep the music going. The system will then keep the music playback service running until it has finished. (You can learn more about the priority given to services in the system by reading Lifecycle of an Android Application.) Note that you can connect to a service (and start it if it’s not already running) with the Context.bindService() method. When connected to a service, you can communicate with it through an interface exposed by the service. For the music service, this might allow you to pause, rewind, etc.

Content Provider
Applications can store their data in files, an SQLite database, or any other mechanism that makes sense. A content provider, however, is useful if you want your application’s data to be shared with other applications. A content provider is a class that implements a standard set of methods to let other applications store and retrieve the type of data that is handled by that content provider.

To get more details on content providers, see Accessing Content Providers.

http://code.google.com/android/intro/anatomy.html

Portions of this page are reproduced from work created and shared by Google and used according to terms described in the Creative Commons 2.5 Attribution License. – Originally posted in Android Community Forums, but excellent enough to share.

I’ve been reading about Powermat for some time now and it always great when I get a Sponsored Post about something I’m interested in. It gives me an opportunity to look a bit closer at the technology and to dig deeper into something which, to be perfectly honest, I wouldn’t mind getting as a Christmas gift.

So, what is the Powermat? It’s an innovative new system to charge your gadgets. The user experience is just awesome; instead of plugging cables and chargers, all you need to do is drop it on a mat and watch it charge. As simple as that. You’ll need to get the correct receiving device on your gadget (so, for example, you need a sleeve for an iPhone), but then it’s just drop and forget. Check out this video about it:

So, how does it work, you might ask. Well, it uses a principle called electromagnetic induction which allows power to transferred over close distances. The Powermat also includes other bits of technology to make the whole thing work together. For example, bother the Powermat and the Power Receiver are RFID enabled so that the mat knows exactly how much power it needs to pour into the device. This also enables the Powermat to shut itself down when the device is fully charged.

The Powermat family includes a number of Receivers for a range of devices, but even has a Receiver which plugs into a mini-USB port, which opens it up to hundreds of devices. And if you have something that isn’t supported, the mat also has a USB socket to provide another alternative.

Anyone out there have one of these? Care to share your experiences?

Here’s what Wikipedia has to say about the modules:

The TKS-derived space capsules, which vaguely resemble a cross between the American Gemini and Apollo capsules, are unique by Russian/Soviet standards. They are equipped to carry three passengers or operate autonomously, but unlike the American capsules the Almaz capsules are reusable from 50 to 100 times. They can launch atop any of several rockets of various spacefaring countries, and they possess a Launch Escape System to ensure the safety of their passengers. They use parachutes and retrorockets to return to Earth, and have soft landing engines which fire just prior to touching down on land. Water-landings are also possible. TKS vehicle/service module design resembles U.S. plans for Manned Orbital Laboratory. Excalibur plans to have multiple options for launch vehicles.

The Almaz-derived space stations are closely related to modules used on the International Space Station, and on the Soviet and Russian Salyut and Mir space stations. This is because the design of the original Almaz (Salyut 2,3, and 5) stations was used as a basis for capsules on Mir and ISS. Excalibur Almaz’s space stations will feature the largest windows ever on spacecraft. Excalibur Almaz owns two complete Almaz space station hulls, but has no plans to outfit them until substantial business experience with the reentry vehicle mounted on a service module laboratory.

I wish them the best of luck, maybe space tourism will become affordable in my lifetime!

There’s a new release of Google’s browser, Chrome that is doing the rounds; which has a set of new features including support for Greasemonkey (Yeay!). There’s still some way to go before it has all the features I’d need to make it my mainstream browser (I’m just too comfortable in Firefox), but considering the last drop was four months ago, I’m pretty impressed at how quick the product is shaping up. Google must be putting some muscle behind it.

So, what’s new? There’s all the details on the release notes, but the highlights are:

• New version of Webkit
• Form Autocomplete
• Full-page zoom
• Spell checking improvements
• Autoscroll
• Docking dragged tabs
• Import bookmarks from Google bookmarks
• SafeBrowsing
• Browser Profiles
• New Javascript engine
• New network code and window frames
• Experimental script support
• HTTPS only mode

Some cool stuff there and some of those features will take it further up the technology scale than most browsers out there.

So, how do you get your hands on it? Here are the steps:

1. If you don’t have Google Chrome, install it from google.com/chrome
2. Subscribe to the developer preview channel. This is required even if you’ve previously subscribed to the channel.
3. Wait until the new version is downloaded (you may force the updatie by opening the “About Google Chrome” dialog).

Note that the developer preview channel will expose you to code that may not be fully tested, but you can always switch back to a safer channel if you wish. It’s nice to see the experience of choosing which stream you want to join made so easy. Anyway, I’ve installed it, and am off to play

• Themes: You can completely change the way GMail looks using themes
• Chat: You can launch video and audio chat right from within your browser, no downloads required
• Backup your email: You can back up your email onto a different platform anytime you want. So you don’t have to feel  you depend on The Big G
• Audit: You can see all the locations you’ve signed in and out from
• Contacts: Contact management is a real breeze on Gmail and integrates nicely with other platforms too.
• Consolidation: GMail lets you consolidate different email accounts in one place
• URLs: As Gmail is web based you can bookmark locations and send them to your friends
• Keep email on your desktop: You can download gadgets and even an entire Google Desktop which integrates nicely with your email
• Search: Google is the master of search and whether you’re looking for milk churners or fat burners you’ll always be able to find them in your mailbox
• Experiment: Google Labs always has new exciting features in development, so if you’re so inclined, you may want to give them a whirl.

Head off and read the post.

I was thinking about technology on my way back from work this afternoon (I have a 15 minute walk which is a great time to think). I was thinking about the first PC I ever got which was an 8086 (with a Turbo button to boost the speed from 4.77 MHz all the way to 10 MHz), CGA graphics and 2 x 5 1/4 disk drives. Oh, and it also had 640k. Now that’s a far cry from the sort of hardware you can buy today.

Organisational computer has changed too. Back in the day it was all about shared mainframes, punched cards and monolithic computer systems. How the landscape has changed. Even hearing about new technologies, like cloud computing or automated OS recovery makes you marvel about how we got from there to here.

The question is .. what will the landscape look like in 10 years?

Interesting news this morning that YouTube has announced that they are going to start featuring full-length movies and episodes which will include in-steam video ads to keep the broadcasters happy. This seems to be a move directed to counter the threat that Hulu affords them, particularly as they have launched similar features to them in the recent past. It seems that shorter videos will still be ad-free, but the full-length features will need to be monitised to support the model they have pursued with their advertisers.

So, down I popped to give it a try and here’s what I get:

Hmm, seems like they’ve decided to omit 95% of Internet users by restricting usage to just one country. I’m hoping that this is for scaling/trial reasons rather than something their broadcasters are insisting on (which is probably the case). The reality is, if they restrict access to this material, then it will just drive users to seek out other services and this will really prevent users from adopting their services.

So, before you throw away your TV, invest in some new modern furniture and high speed satellite internet and a new giant monitor for your computer, check if the service works in your area. You may be disappointed, I know I was.

Sometimes, it takes a small problem to make one realise how little he actually knows. I personally know a fair bit about all sorts of technology, ranging from networks, to development to integration; however I haven’t really had much experience with Linux. It’s partly because most of the services I use are nicely packaged, but also because I’m mostly grounded in a Microsoft world in my day-to-day job. But it was great to find that thanks to the Internet I can research a problem and solve problems too.

Last night I started dealing with a problem were a PHP component I had written some time back has stopped working after a server move. Looking through the logs I could see that the error I was getting was:

PHP Fatal error: require_once() [<a href='function.require'>function.require</a>]: Failed opening required 'XML/RSS.php' (include_path='.:/usr/share/pear:/usr/share/pear/XML') in /var/www/vhosts/xxx/httpdocs/site_elements/register.php on line 6

Okay I thought, it must be that the PEAR component I needed wasn’t available. PEAR stands for PHP Extension and Application Repository and is a framework and distribution system for reusable PHP components. I needed the RSS component which was used by my code. I eventually got myself SSH access to the box and deployed the components (also finding out that I needed a couple of prerequisite packages). The way you do this is:


pear install XML_Parser
pear install XML_Tree
pear install XML_RSS


This downloads and deploys the required components for you into /usr/share/pear. But my code still wouldn’t run.

Eventually I found out that this was becuase PHP was running in “safe mode“. Safe mode is a way to protect PHP from different users on the same server, but this was a dedicated server so I didn’t really need it on. One thing that safe mode does is that it stops you from including files from other directories. This was coupled with another parameter “open_basedir” that limits the files that can be opened by PHP to a specified directory tree (which didn’t include /usr/share. so that needed to be rectified too.

I did my reading, open SSH again and proceeded to update my php.ini file to adjust these settings. I saved it, tried the site again. Still exactly the same error.

Reading a bit more around the subject, I discovered that each website also has it’s own httpd.conf file which overrides php.ini, so the search was on once again to find more of these settings. Sure enough, I found this configuration file, modified it, saved it and tried the site again. Still the same error.

At this point I ran out of things to try, so like all techies I figured, maybe I need to restart Apache to read the settings again. You know, the traditional “turn it off and turn it back on again”. Being a noob when it comes to Linux I logged into my control panel, stopped the site and started it again. Still the same error.

Eventually I got to the bottom of it. Stopping and starting the site didn’t quite restart the service the way I wanted it to. The REAL way to do it is with the following command (again in SSH)

service httpd graceful


And would you know it .. the problem is now solved!

I thought I’d document the process here for two reasons. If you’re trying to solve this problem you may find these steps useful. You may need this if you go into fixing people’s technical problems, there may be a franchise opportunity there somewhere. And I’m pretty sure I’ll need to do this again one day, so it’s always a good idea to write it down!

It should be available in the US and UK by the “end of the year“, but this particular offering will be locked to T-mobile (until someone writes an unlock for it). However, the OS is open source, so it won’t be long before a whole host of other mobile phones could be running it. Expect a number of gadget sites to be publishing instructions on how to install it on unlocked cell phones with the right specification as it becomes more and more commonplace.

I’m still on my Windows Mobile XDA here. It does the trick but I’d love to get my mitts on one of these.