Flex Interview Questions-Part1

A few interview questions with answers on flex,

1. Is it possible to make httpService Requests synchronous?
A: No.
Solution : Basically, what we are about to do is creating XMLHttpRequest with Javascript in Flex,
and calling a server data with the parameters we will give to the object.
For example: xmlHttpRequest.open("GET","http://localhost/Default.aspx",false);
1. Request Type: GET or POST

2. Requested URL

3. Communication Type: true for asynchronous, false for synchronous.

2. I need to load an image from flickr into my application. Do I need a crossdomain.xml file on flickr?
A: File is already there , we need to register our ip address to flicker’s crossdomain.xml
? : Since the images are located on a flickr server like farm1.static.flickr.com and there is no
crossdomain.xml file on that server (there is a crossdomain.xml for api.flickr.com so you can use the
api) that means you can’t get access to the bitmapData of the loaded images when you load them
from flickr. This is dumb, but that’s the way it is. So you can load images just fine, but the reflection
class copies the bitmapData of the image, so that doesn’t work if you load them straight from the
flickr server. I also wanted to set bitmap smoothing to true on the images so the thumbnails don’t
look as pixelated, and that also requires access to the bitmapData of the loaded image.

So the answer is to create a proxy that loads the flickr image so it appears to come from the same

domain.

3. What is the difference between httpService and Data Service?
A: The services-config.xml configuration file is required at compile time if the Flex application uses
Flex Data Services. In the case of RPC services, this applies to all applications that use
RemoteObject or proxy-based WebService or HTTPService.