Question

<scxml 
xmlns="http://www.w3.org/2005/07/scxml"
version="1.0"
profile="ecmascript"
initial="idle">

<state id="idle">
    <transition event="mousedown" target="dragging"/>
</state>

<state id="dragging">
    <transition event="mouseup" target="idle"/>
    <transition event="mousemove" target="dragging"/>
</state>

</scxml>

I want to parse this xml when i start the application i enter the initial state that is “idle” then when my event completed i want to move the next state “dragging”. how can i do this?

I am using NSXmlparser in the following method.

-(void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict{
if ([elementName isEqualToString:@"scxml"])

{
    stateID = [attributeDict objectForKey:@"initital"];
    stateInfo = [[StateInfo alloc]initWithStateName:stateID];
    return;

}
if ([elementName isEqualToString: @"state"] ){

    if ([[attributeDict objectForKey:@"transition"] isEqualToString:@"idle"])  {

    }
    else {

    }
}
//    if ([elementName isEqualToString:@"state"]) {
////        stateID = [attributeDict objectForKey:@"id"];
////        stateInfo = [[StateInfo alloc]initWithStateName:stateID];
////        NSLog(@"stateID = %@",stateID);
//        return;
//    }
if([elementName isEqualToString:@"transition"]){
    //aList=[[List alloc]init];
    stateID = [attributeDict objectForKey:@"target"];
    targetStateInfo = [[StateInfo alloc]initWithStateName:stateID];
    [stateInfo registerNextState:targetStateInfo withCondition:[attributeDict objectForKey:@"cond" ]];
    return;
}
if ([elementName isEqualToString:@"scxml"])

    {
    stateID = [attributeDict objectForKey:@"initital"];
    stateInfo = [[StateInfo alloc]initWithStateName:stateID];
    return;

  }
if ([elementName isEqualToString: @"state"] ){

    if ([[attributeDict objectForKey:@"Name"] isEqualToString:@"Child2"])  {
        // searchDone=YES;
    }
    else {
        // searchDone=NO;

    }
}
//    if ([elementName isEqualToString:@"state"]) {
////        stateID = [attributeDict objectForKey:@"id"];
////        stateInfo = [[StateInfo alloc]initWithStateName:stateID];
////        NSLog(@"stateID = %@",stateID);
//        return;
//    }
if([elementName isEqualToString:@"transition"]){
    //aList=[[List alloc]init];
    stateID = [attributeDict objectForKey:@"target"];
    targetStateInfo = [[StateInfo alloc]initWithStateName:stateID];
    [stateInfo registerNextState:targetStateInfo withCondition:[attributeDict objectForKey:@"cond" ]];
    return;
  }

}

-(void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string{

if(!currentElementValue){
    currentElementValue=[[NSMutableString alloc]init];
}
[currentElementValue appendString:string];
//currentElementValue = (NSMutableString *) [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
 /* if(!currentElementValue)
 currentElementValue = [[NSMutableString alloc] init];
 else
 [currentElementValue appendString:string];
 */

/* if(self.currentElementValue)
{
[self.currentElementValue appendString:string];
}
*/
}

-(void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName{
if ([elementName isEqualToString:@"scxml"])
    return;
if([elementName isEqualToString:@"state"]){
    //[aList setTitle:currentElementValue];
    //NSLog(@"alist.title = %@",aList.title);
}
    currentElementValue = nil;
 }

Answer 1

This code you have commented seems to be fine:

if ([elementName isEqualToString:@"state"]) {
        stateID = [attributeDict objectForKey:@"id"];
        stateInfo = [[StateInfo alloc]initWithStateName:stateID];
        NSLog(@"stateID = %@",stateID);
}

stateID will show idle the first time and dragging the second time.

The xml is read from the top to the bottom

for <state> or similar tags you have to use if ([elementName isEqualToString:@"state"])

for attributes inside the tags like target=””, event=”” or id=”” you have to use [attributeDict objectForKey:@"target"];

You don’t have to do anything special, when the parser finish the first </state> it will continue with the next <state>.