How to Store User Preferences in an Adobe Flex/AIR Application

What's the stan开发者_如何学编程dard way of storing user preferences in a Flex application for AIR? I need to store simple parameters like lists of recently opened files, window positions and sizes etc.

my favorite way to do it is to combine a VO with LSO (local shared object). If you have a LOT of settings, this doesn't work too well. The advantage is that you get a strongly typed settings object which is therfore bindable and has code introspection and completion.

The cool thing is it's only about 5 lines of code to manage an LSO. In addition, it's also pretty easy to manage a local encrypted store if you want to store any sensitive data.

registerClassAlias("SettingsVO",SettingsVO);  //This lets us store a typed object in LSO
var settings:SettingsVO;
var settingsSO = SharedObject.getLocal("settings");   
//Check to make sure settings exist... if not, create a new settings object
if( settingsSO.size && settingsSO.data && settingsSO.data.settings){
    settings = settingsSO.data.settings as SettingsVO;
}else{
    settings = new SettingsVO();
}

Now if you want to save settings you simply do

settings.someSetting = "newValue";
settingsSO.data.settings = settings;
settingsSO.flush();

And this solution works on BOTH AIR and Flex in any browser. Newer browsers will delete this data when clearing cookies, so beware of that.

I think the most flexible way is to use a local SQLite database. It gives you unlimited, structured storage and encryption if needed. See Peter Elst's introduction if you want to get more info.

There is no "Standard" way, but there are a lot of approaches, all which boil down to storing the user's preferences, then loading them up at runtime based on some uesr credentials, then changing the app based on those preferences.

You may store them in a server side database, such as SQL Server or MySQL; then have flex call a service which queries the database and returns the data.

You may store them as Shared Objects, which are the Flash version of browser cookies. (I believe they work on AIR applications too). This can get cumbersome with lots of data.

You may store them in an XML document and throw them on the server. Conceptually this is not much different than storing them in a server side database; but could get very tedious if you have a lot of users.

You could also store them, in an AIR app, locally using a SQLite database. SQLite is an embedded database used in Adobe AIR.

I don't bother with any of the fancy stuff. Just store it in an xml file in the application directory. Done.

Filestream does throw an error if you try to store it using File.applicationDirectory. I just trick the program...

var trickFile:File = File.applicationDirectory;
var file:File = new File(trickFile.nativePath + mySettings.xml);

Air falls for it every time.