Pass a function when calling onClick for a button (UI)

[warm_reality157F]

Hi

I´m now studying and adventuring myself in the Script UI creation. I´m enjoying it !!!

I´m having the following trouble: I added a button to a dialog box and would like to tell script to run some commands when users click on the button. So this is a simple (poor example):

var dlg = new Window ("dialog", "My dialog", [0,0,0,0])

dlg.size = [500,500]

dlg.location = [300,300]

var b = dlg.add("button", [0,0,0,0], "Run")

b.location = [20, 180]

b.size = [80, 30]

dlg.show()

b.onClick = test () //the problem is here

function test(){

  alert("teste")

}

-------

Everything is right. But the onClick event does not execute the function test I´m passing! What Am I missing?

I know if I use

b.onClick = function (){

...

}

It works...but I´d like the function to be called instead of directlly created when calling the onClick. Do not know if I´m able to explain it better.

Thank you for the help

Best Regards

Gustavo.

[warm_reality157F]

P.S: the way I wrote my example....function will execute when I close the dlg dialog.

And if I write the function at beggining it will autoexecute before dialog box be showed.

Looks it´s running the function automatically in the sequence of the commands! Not what I expect to be.

Thank you a lot

Gustavo.

[Paul Riggott · Accepted solution]

The norm would be ...

var dlg = new Window ("dialog", "My dialog", [0,0,0,0])
dlg.size = [500,500]
dlg.location = [300,300] 
var b = dlg.add("button", [0,0,0,0], "Run")
b.location = [20, 180]
b.size = [80, 30] 
b.onClick = function(){ //the problem is here
test();
}
dlg.show()
function test(){
  alert("teste")
}

[warm_reality157F]

Hi Paul

Interesting. So EVERY onClick, onClose, onOpen, onChange ... events must receive a function??

And sure we can call other functions inside them.

Thank you a lot

Gustavo.

[Michael_L_Hale]

Interesting. So EVERY onClick, onClose, onOpen, onChange ... events must receive a function??

No, you don't need to create a function for every control or evert type. Some controls have default handlers and you only need to define new ones if you want to change the default action.

[warm_reality157F]

Thank you Michael. That worked too.

Can you give an example of controls with default handler that I do not need to create a function?

Thank you a lot

Best Regards

Gustavo.

[Michael_L_Hale]

You need to define the control's callback before you show the dialog so you should move b.onClick = test; to above the dlg.show() line.

If you want the onClick to use the test function use b.onClick = test;

b.onClick = test() asssigns the results of the test function( if any ) to the onClick so here it's undefined.

I have found that sometimes using alert or $.writeln doesn't work in a dialog control event callback.