Forum Discussion

jbrave's avatar
jbrave
Channel Surfer
15 years ago

parsing XML question

I'm getting an xml feed and trying to extract some data. With tags like

<name>Joseph</name>
it works just fine.


but with With tags like:
<file-count type="Integer">30</file-count>

I get this error:

/tmp/plugin/HJAAAAREIkOr/pkg:/source/main.brs(33): runtime error ec: 'Dot' Operator attempted with invalid BrightScript Component or interface reference.

033: tcs=xml.file-count.GetText()

and:

tcs &h30 Untyped val:Uninitialized

Can anyone help? How do get the value of a tag that has subsidiary information in it like "type"? Should I declare tcs as an integer first? It doesn't seem to help. Do I need to do a test of some kind on each xml key before I attempt to assign it to a variable?

Thanks!
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37 Replies

  • kbenson's avatar
    kbenson
    Visitor
    15 years ago
    "-" is not a valid variable character. Use one of the alternate access methods, such as a member function, to access the element. The Reference manual mentions this when referring to the need to do case sensitive matching, so it will most likely work here as well.
  • jbrave's avatar
    jbrave
    Channel Surfer
    15 years ago
    Ok, looks like you are correct that the - is the cause of the problem. Now how do I get that xml tag without using the dash character - it is in the xml feed and there are many other xml tags that have that character as well
  • TheEndless's avatar
    TheEndless
    Channel Surfer
    15 years ago
    The roXMLElement component has a GetNamedElements() method. You should be able to use that to get an roXMLList of the "file-count" elements that you can loop through.
  • jbrave's avatar
    jbrave
    Channel Surfer
    15 years ago
    Thanks for responding. I don't see any examples of actual usage of GetNamedElement in the documentation. I'm searching through the examples also, and the videoplayer which actually parses XML doesn't use this function. Can you post an example of how GetNamedElement is actually used?
  • hoffmcs's avatar
    hoffmcs
    Visitor
    15 years ago
    In your case it would be:
    xml.GetNamedElement("file-count")[0].GetText()
  • jbrave's avatar
    jbrave
    Channel Surfer
    15 years ago
    Thanks! So, how would one know that a function like GetNamedElement would be called like this, as opposed to xml.tagname.GetNamedElement() ?

    What do I look for when reading the Developer manual to know if a function gets called like:

    something.Function() or if it gets called like:

    Function("something")

    In other words, how did you come up with that statement and know that it works?

    - Joel
  • hoffmcs's avatar
    hoffmcs
    Visitor
    15 years ago
    It is documented in the SDK. Look at section 10.16 in the Brightscript Reference Manual. There are also some examples in the generalUtil.brs files found in some of the example channels.
  • jbrave's avatar
    jbrave
    Channel Surfer
    15 years ago
    Thanks, I read the manual section you suggested again, and I understand a little bit better now. However, I still don't understand all the aspects of that code you posted. What is the [0] about, seems like an array reference, but why is it needed when there is already the name of the tag in the parenthesis:

    xml.GetNamedElement("file-count")[0].GetText()

    Thanks,

    Joel
  • TheEndless's avatar
    TheEndless
    Channel Surfer
    15 years ago
    "jbrave" wrote:
    Thanks, I read the manual section you suggested again, and I understand a little bit better now. However, I still don't understand all the aspects of that code you posted. What is the [0] about, seems like an array reference, but why is it needed when there is already the name of the tag in the parenthesis:

    xml.GetNamedElement("file-count")[0].GetText()

    Thanks,

    Joel

    The name of the method is actually GetNamedElements and it returns an roXMLList, so you need to get the first index of that list to get the XML element you're looking for. The safest way to do this is probably...


    xmlFileCount = xml.GetNamedElements("file-count")
    If xmlFileCount <> invalid And fileCount.Count() > 0 Then
        fileCount = xmlFileCount[ 0 ].GetText()
    End If

    With that, you won't blow up if the element is missing from your XML for some reason.
  • jbrave's avatar
    jbrave
    Channel Surfer
    15 years ago
    Thanks for catching that typo, I was just starting to pull hair(s) out of my head over it.

    So I'm now trying to understand the new bit of code you posted,

    where did you get FileCount.Count() from, or is that a typo for xmlFileCount?

    - Joel