The constructor XMLRequest (weatherclass.WeatherClass(int, int) is undefined

That compile error can mean either of these:

• 1 or more of the parameter types are wrong. Perhaps it's not int.
• number of parameters is wrong
• perhaps it got no parameter at all

Sorry if I skimmed too fast, but your error seems like it can be solved by the following article in the Technical FAQ:
Why I can't create an instance of a library from my own classes?

Hi,
I tried to ammend based on the article you directed me to. I don't think I've  fully understood it, though I tried various experiments, I still can't get the code to work, This is where I got:
"The constructor Yahoo_weather_class.WeatherClass(Yahoo_weather_class, int) is undefined"

Wonderful if you can take another look
thanks


import simpleML.*;

WeatherClass dotObject;
//-------------------------------------
void setup() {
  size(200, 200);
  smooth();

  dotObject = new WeatherClass (this,1 ); // not sure what to put here after this

}
//-----------------------------------

void draw() {
  background(255);
  dotObject.display();
}
//////////////////////////

class WeatherClass {
  int x,y;
 int temperature;
 int weather;
String url ="http://weather.yahooapis.com/forecastrss?w=26360988&u=c";
  //-----------------------------------
  WeatherClass (PApplet pa,String url) {
    XMLRequest xreq = new XMLRequest(pa, url);
    xreq.makeRequest();
  }

  void display() {
    dot();
  }
  //-----------------------------------
  void getWeather() {
    String url = "http://weather.yahooapis.com/forecastrss?w=26360988&u=c";
    XMLRequest req = new XMLRequest(this, url);
    req.makeRequest();
    println ("loaded from xml.weather.yahoo.com");
  }
  //-----------------------------------
  void netEvent(XMLRequest ml) { // Get the specific XML content we want
    temperature = int(ml.getElementAttributeText("yweather:condition", "temp"));
    weather = int (ml.getElementAttributeText("yweather:condition", "code"));
  }
  //-----------------------------------
  void dot () {

    fill (255,0,0);
    ellipse (weather*3, temperature*3, weather, weather);
  }
}

Like I had explained before: you're using wrong types when instantiating your WeatherClass!

Constructor ->  WeatherClass(PApplet pa, String url) {...} -> demands a PApplet + a String type parameters!

However, instead of a String one, you force an int type?!

As said... Only the PApplet parameter is mandatory, the remainder is optional and depends on your needs.

1. import simpleML.*;
2. WeatherClass dotObject;
3. //-------------------------------------
4. void setup() {
5.   size(200, 200);
6.   smooth();
7.   dotObject = new WeatherClass(this);
8. }
9. //-----------------------------------
10. void draw() {
11.   background(255);
12.   dotObject.display();
13. }
14. //////////////////////////
15. class WeatherClass {
16.   int x,y;
17.  int temperature;
18.  int weather;
19. String url ="http://weather.yahooapis.com/forecastrss?w=26360988&u=c";
20.   //-----------------------------------
21.   WeatherClass (PApplet pa) {
22.     XMLRequest xreq = new XMLRequest(pa, url);
23.     xreq.makeRequest();
24.   }
25.   void display() {
26.     dot();
27.   }
28.   //-----------------------------------
29.   void getWeather() {
30.     String url = "http://weather.yahooapis.com/forecastrss?w=26360988&u=c";
31.     XMLRequest req = new XMLRequest(this, url);
32.     req.makeRequest();
33.     println ("loaded from xml.weather.yahoo.com");
34.   }
35.   //-----------------------------------
36.   void netEvent(XMLRequest ml) { // Get the specific XML content we want
37.     temperature = int(ml.getElementAttributeText("yweather:condition", "temp"));
38.     weather = int (ml.getElementAttributeText("yweather:condition", "code"));
39.   }
40.   //-----------------------------------
41.   void dot () {
42.     fill (255,0,0);
43.     ellipse (weather*3, temperature*3, weather, weather);
44.   }
45. }

Hiya,
Sorry, still no luck, now the "constructor XMLRequest  is undefined"- line 31-
but how do I work here with the this- PApplet pa?

try line 31

1.     XMLRequest req = new XMLRequest(pa, url);

Hiya,
I tried that, but no luck,
thanks for the suggestion

the method getWeather is not in use

why not comment it out
//

As I see it, line 30 is still inside the class (to line 45)

so url is already known (line 19) and doesn't need to be re-invented (line 30)

same goes for req

if you would say

1.     XMLRequest xreq ;

after line 19 and
change line 22 to

1.     xreq = new XMLRequest(pa, url);

great, thanks!
I can load the url. !
 it  works

I now need to get my head around the next step- getting the information from the url content.
With the join and split method I managed, ( and in the 'classless' version at the top).-but here I'm hitting the ground again.
Sorry to be so clueless. I just can't see it.
maybe tomorrow....

in line 36

1.   void netEvent(XMLRequest ml) { // Get the specific XML content we want
2.     temperature = int(ml.getElementAttributeText("yweather:condition", "temp"));
3.     weather = int (ml.getElementAttributeText("yweather:condition", "code"));
4.   }

1. dotObject.netEvent ( dotObject.xreq );

so you set the values for weather and temperature in the class /object.
They are used by the method display so we have to get them right first.

When the value in the yahoo database changes you need to call getWeather too (but you need to rewrite it or you have done this already).
draw() then looks like this:

1. //-----------------------------------
2. void draw() {
3.   background(255);
4.   dotObject.getWeather ();
5.   dotObject.netEvent ( dotObject.xreq );
6.   dotObject.display();
7. }

Please show your entire code when you're here next time. It makes it easier to follow. Thanks.

Greetings, Chrisir    

Hiya, after a day's break:
I applied your suggestion ( I hope in the right way) but get the NullpointerException, when I place : "dotObject.netEvent ( dotObject.xreq )" in the draw. If I cancel it out I do manage to get the url loaded as before.

Below you will also find another version of the same idea in code, which does work. I just really want to understand what is going wrong here- this approach seems a bit more straightforward

weather object using this and PPapplet pa:
-----------

  import simpleML.*;
    WeatherClass dotObject;
    //-------------------------------------
    void setup() {
      size(200, 200);
      smooth();
      dotObject = new WeatherClass(this);
    }
    //-----------------------------------
    void draw() {
  background(255);
 
 // dotObject.netEvent ( dotObject.xreq );
  dotObject.display();
}
    //////////////////////////
    class WeatherClass {
      int x,y;
     int temperature;
     int weather;
    String url ="http://weather.yahooapis.com/forecastrss?w=26360988&u=c";
     XMLRequest xreq ;
      //-----------------------------------
      WeatherClass (PApplet pa) {
        //XMLRequest xreq = new XMLRequest(pa, url);
           xreq = new XMLRequest(pa, url);
        xreq.makeRequest();
      }
      void display() {
        dot();
      }
    
      //-----------------------------------
      void netEvent(XMLRequest ml) { // Get the specific XML content we want
        temperature = int(ml.getElementAttributeText("yweather:condition", "temp"));
        weather = int (ml.getElementAttributeText("yweather:condition", "code"));
      }
      //-----------------------------------
      void dot () {
        fill (255,0,0);
        ellipse (weather*3, temperature*3, weather, weather);
      }
    }

version 2: weather object using the Weathergrabber code form learning processing

WeatherClass dotObject;

void setup() {
  size(200, 200);
 // Make a WeatherClass object
  dotObject = new WeatherClass();//  initialising the object
 
}

void draw() {
  background(255);
dotObject.display();

}


/////////////////

class WeatherClass {
  int temperature = 0;
  int code = 0;

  WeatherClass() {
    requestWeather();//loading the XML data

  }
void display(){
   fill (255, 0, 0);
    ellipse (code*5, temperature*3, code, code);
 
   // Get the values to display
  text("weathercode: " + code, 10, 90);
  text("temperature: "+ temperature, 10, 40);
 
}
  // Make the actual XML request
  void requestWeather() {
    String url = "http://weather.yahooapis.com/forecastrss?w=26360988&u=c";//weather Brighton
    String[] lines = loadStrings(url);
    String xml = join(lines, "" ); // make all the xml source code into one long array
 String lookfor = "code=\"" ; // find the specific elelment in the sourcecode of Yahoo
    String end = "\"";
   
   code = int (giveMeTextBetween(xml, lookfor, end));
    lookfor = "temp=\"";
   temperature = int(giveMeTextBetween (xml, lookfor, end));
    
  }
  // A function that returns a substring between two substrings
  String giveMeTextBetween(String s, String before, String after) {
    int start = s.indexOf(before);    // Find the index of the beginning tag
 start += before.length();         // Move to the end of the beginning tag
   int end = s.indexOf(after, start); // Find the index of the end tag
    return s.substring(start, end);    // Return the text in between
  }
}