Question

I’m working on my first real Flex app and i have learned a lot by it. Now I’m trying to understand the basics of working with classes. I have a function that asks information from the LastFm API. This is the base function:

        public function zoekChart(event:MouseEvent):void
        {
            var api_URL:String = 'http://ws.audioscrobbler.com/2.0/';
            var api_method:String = 'geo.getMetroUniqueArtistChart';
            var api_key:String = '99f1f497c0bd598f1ec20571a38e2219';
            var country:String = countryText.text;
            var metro:String = metroText.text;
            var limit:String = '5'; 
            api_request = api_URL + '?method=' + api_method + '&country=' + country + '&metro=' + metro + '&api_key=' + api_key + '&limit=' + limit;
            myRequest.send();
        }

Now I’m trying to make a class which does the same as the function. This is what i have so far:

package valueObjects
{
public class Kevin_myChart
{
    private var api_URL:String;
    private var api_method:String;
    private var api_key:String;
    private var country:String;
    private var metro:String;
    private var limit:String;

        public function lastFMCall (api_URL:String, api_method:String, api_key:String, 
                                     country:String, metro:String, limit:String) 
        {
            this.api_URL=api_URL;
            this.api_method=api_method;
            this.api_key=api_key;
            this.country=country;
            this.metro=metro;
            this.limit=limit;
        }

        public function getInfo(size:String):String 
        {

            return api_URL + '?method=' + api_method + '&country=' + country + '&metro=' + metro + '&api_key=' + api_key + '&limit=' + limit;

        }   
}

}

Is this a good start? My first question is how i can import the values of textfields countryText and metroText in the class.

Also, how should I continue from here? How can i make sure that my application will be able to use the functions declared in the class and how can i get values in the class’s vars now?

Answer 1

You can use your class’s constructor to pass the values. A constructor is called when you create a new instance of your class.

public function zoekChart(event:MouseEvent):void
{
    var api_URL:String = 'http://ws.audioscrobbler.com/2.0/';
    var api_method:String = 'geo.getMetroUniqueArtistChart';
    var api_key:String = '99f1f497c0bd598f1ec20571a38e2219';
    var country:String = countryText.text;
    var metro:String = metroText.text;
    var limit:String = '5'; 

    // create a new instance of your class
    var kevinMyChart:Kevin_myChart = new Kevin_myChart(api_URL, api_method, api_key:, country, metro, limit);

    // not sure what the 'size' is used for
    api_request = kevinMyChart.getInfo("size");
    myRequest.send();
}

Your Kevin_myChart class with constructor:

package valueObjects
{
    public class Kevin_myChart
    {
        private var api_URL:String;
        private var api_method:String;
        private var api_key:String;
        private var country:String;
        private var metro:String;
        private var limit:String;

        public function Kevin_myChart(api_URL:String, api_method:String, api_key:String, country:String, metro:String, limit:String) 
        {
            this.api_URL=api_URL;
            this.api_method=api_method;
            this.api_key=api_key;
            this.country=country;
            this.metro=metro;
            this.limit=limit;
        }

        public function getInfo(size:String) : String 
        {
            // not sure what the 'size' is used for    
            return api_URL + '?method=' + api_method + '&country=' + country + '&metro=' + metro + '&api_key=' + api_key + '&limit=' + limit;

        }   
    }
}

Your getting in the right direction, maybe this tutorial will give you some more info about the way a class is build.

http://www.kirupa.com/developer/as3/classes_as3_pg3.htm

Otherwise a quick Google Search could help you further aswell.