Java slider not Responding

The slider is saved as S.sl1 and I convert it to sl1 and output it. I then convert it to a java slider in another function with :

   jScrollBar = findjobj(sl1);
   jScrollBar.AdjustmentValueChangedCallback = @updateplot;

Then the call back function is:

function updateplot(sl1,ht,funcNum)

x = get(sl1,'Value');
Beam.Location = x;

switch funcNum
    case funcNum == 1
        y = Cantilieverd_Point(Beam);
        set(ht,'ydata',y);
        drawnow;

      case funcNum == 2
          y = Simple_Point(Beam);
          set(ht,'ydata',y);
          drawnow;
  end

end

Where ht is the plot that is being updated and the ' y = ' is another function which creates the y value. When I run this it does not return an error, but it also does absolutely nothing to the graph. I want it to continuously update the graph based off of the slider value.

[Matt Fig]

Just a note:

When you post code that relies on a FEX file, you should state that and give a link so people don't try to copy/paste your code only to get an error...

[Matt Fig]

Also, were you not able to make the addlistener code work?

[Malcolm Lidierth]

How does updateplot know the value of funcNum? ht is an EventData object - it has no 'ydata' property. Is this a slider or a scrollBar.

The callback can not be being called - or you would see errors.

A more complete code example is needed to be more helpful.

[Lawson Hoover]

@ Matt Fig, well the Listener did work in a way. It would update once and then not run again. To tell you the truth I might just move on past this and come back to it later. I am still very new to MATLAB and still trying to get a hold of the concepts.

[Malcolm Lidierth]

@Lawson That is a vital bit of info. The callback is evaluated once, throws an exception and gets removed by MATLAB. You need something like:

jScrollBar.AdjustmentValueChangedCallback = {@updateplot, ht, funcNum};

The callback should then be declared as:

function updateplot(sl1,EvenData, ht, funcNum)

sl1 and EventData are added automatically to the inputs by MATLAB>

Answer 1

[Jan]

There are several problems in your code:

1. Here the callback is defined with no inputs:

jScrollBar.AdjustmentValueChangedCallback = @updateplot;

But in the definition of the callback function, 3 inputs are required.

2. Look at the documentation of switch/case again. The term "funcNum==1" is evaluated to either true or false, but you want to switch for the value 1 or 2. Therefore you need:

switch funcNum
  case 1   % Not "funcNum == 1"
    ...

I suggest not to use a Java slider, but the standard Matlab sliders. You cann attach a listener to them also: http://www.mathworks.com/support/solutions/en/data/1-3SR0YI/index.html?product=ML&solution=1-3SR0YI