One of the great features of mobile RIAs is the fact that you can connect your application to all kinds of different server technologies, such as PHP, Java, ColdFusion, .NET, … in exactly the same way as you would in your desktop AIR application. You can even work with the DataService component to use real-time data connections over the RTMP channel. Just think about real-time stock updates, video streaming, trader applications on mobile, collaboration across multiple devices … The sky really is the limit. Or is it?

I think all of this always sounds very nice, but people tend to forget one important thing when working on a mobile device and that is that if you’re not on a WiFi connection, your data contract can become very expensive when you use the sever connections. However, in Flex 4.5 there is a way to actually check whether you are working on your data contract or on a WiFi connection.

In the application you can access all of the device interfaces and check to see whether they are active or not. The only thing you need to know is which interface to look for. In the code below, you can see how I check for the “WiFi” and “mobile” interfaces. Based on what I find, I just check whether it is active. Remember, some people may have the possibility to work via a data contract, but didn’t sign up for it, so finding the “mobile” interface isn’t enough.

<?xml version="1.0" encoding="utf-8"?>
<s:View xmlns:fx="http://ns.adobe.com/mxml/2009" 
		xmlns:s="library://ns.adobe.com/flex/spark" 
		title="Connection Test"
		creationComplete="initView()">
 
	<fx:Script>
		<![CDATA[
			private function initView():void {
				var interfaces:Vector.<NetworkInterface> = NetworkInfo.networkInfo.findInterfaces();
 
				for(var i:uint = 0; i < interfaces.length; i++) {
					if(interfaces[i].name.toLowerCase() == "wifi" && interfaces[i].active) {
						lbl.text = "WiFi connection enabled";
						break;
					} else if(interfaces[i].name.toLowerCase() == "mobile" && interfaces[i].active) {
						lbl.text = "Mobile data connection enabled";
						break;
					}
				}
			}
 
		]]>
	</fx:Script>
 
	<s:Label id="lbl" horizontalCenter="0" verticalCenter="0"/>
</s:View>

In this example I’m simply setting the text property of a label, but you can also use this in a real world application to determine the update rate for your server data, for example.

There is one thing you should not forget to do when creating such an application. You have to set the proper permissions in the <applicationName>-app.xml file, in the android section. That section should contain the ACCESS_NETWORK_STATE and the ACCESS_WIFI_STATE permissions in order for it to work. If you don’t include this, you will get an empty Vector returned from the findInterfaces method.

<android>
    <manifestAdditions><![CDATA[
	<manifest>
		<!-- See the Adobe AIR documentation for more information about setting Google Android permissions -->
		<uses-permission android:name="android.permission.INTERNET"/>
		<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
		<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
	</manifest>
]]></manifestAdditions>
  </android>

This one works over the internet as well, since it simply downloads a CVS file every 10 minutes to automatically update the application. The design was made in Illustrator, brought into Flash Catalyst to get the arrow working and finally I took it to Flash Builder to attach the HTTPService that fetches the data. You can read the full implementation in my book "Flash Builder and Flash Catalyst: The New Workflow" as well, since it’s one of the many examples in there.

The second application is a remote control for my BTicino domotics system. I’ve been wanting to do this for a very long time now. But up until now I just couldn’t do it, because you couldn’t create this thing in Flash Lite 3. But now, with AIR on Android (and soon on other mobile platforms as well) I could create a socket connection to my MH200 controller and feed it directly with my input to control the shutters and lights. Naturally, the possibilities are only limited by your imagination.

Both applications are Flex 4 applications, which proves that, despite the fact that the Flex framework isn’t optimised for these mobile devices and Slider (special Flex framework for mobile) isn’t yet available, the application still works pretty damn well. Loading times are not that bad either. Imagine what an optimised Flex framework will be able to perform then…