AppletTalk.com

ryanoasis · Guest

I am new to Java applets and therefore japplets as well.
I am working on a project that we want to get the params from the page
the applet tag is on. I have looked at

the various examples and they are not working for the application I am
working on however when I make my own

simple sample it works just fine.

This is the error I get when trying it in the project:

java.lang.NullPointerException
at java.applet.Applet.getParameter(Unknown Source)

I have read that the getParameter call should be in init and also in
the default constructor. This doesnt

seem to work however, I have tried the call in many other methods and
also calling it from a seperate class.

String s ="initial";
s = getParameter("asdf");

<param name="asdf" value="hi">

Thanks.

Andrew Thompson · Guest

ryanoasis wrote:
...

Tom Hawtin · Guest

ryanoasis wrote:

ryanoasis · Guest

Sorry I meant I read that it should be in the default constructor OR
the init method.

It is obvious after viewing the replies I wasn't completely clear and
that is probably because
I don't know much about the general workings of a Java applet at this
point well enough to
explain what I am trying to do.

Yes apparently I didn't ask a question my apologies, I suppose in
hindsight my question was
what could be causing an issue with get parameters when it does work
with a simple example?

"A constructor with no arguments is
generally referred to as a "no-args constructor". "

Generally? All books that I have read have almost always called it a
default constructor but thank you
for the extra info.

Andrew Thompson · Guest

ryanoasis wrote:

(applet)

ryanoasis · Guest

I will look into that.

I have found a way to get it to work (although I'm sure its less than
great):

// CLASS TO HANDLE PARAMS:

public class MAParam extends JApplet {

public static String myStatic = "init static";

public void init()
{
myStatic = getParameter("count");
}
}

// HTML:

<html>
<body>

<applet code="MAParam.class" width="0" height="0">
<param name="count" value=2 />
</applet>
<applet code="ClassIDidntWrite.class" width="800" height="550">
</applet>
</body>
</html>

// CLASS: ClassIDidntWrite
private static String PARAM;
public ClassIDidntWrite() {
PARAM = MAParam.myStatic;
System.out.println("PARAM IS: " + PARAM);
System.out.println("MyStatic IS: " + MAParam.myStatic);
...