[patch][cla]Support for event suspend/resume

[Tom Trenka]

Add support to dojo.connect for suspending and resuming connections. Patch attached, original from Scott Miles.

[Tom Trenka]

Added documentation with example for using suspend() and resume():

var link=dojo.connect(obj, "foo", obj, "bar");
...
link.suspend();
...
link.resume();
...
dojo.disconnect(link);

[guest]

From within a widget, you have to get the last handle:

var handles = this.connect(this.someNode, "onclick", function(evt){
    /* handler code goes here */
});
var link = handles[handles.length-1];
...
link.suspend();
...
link.resume();

-Chris Barber

[bill]

Replying to guest:

From within a widget, you have to get the last handle:

Actually, if you do want to support this feature from _Widget.connect(), you need to suspend/resume every element in the handles array, not just the last one.

[cb1kenobi]

Replying to bill:

Replying to guest:

From within a widget, you have to get the last handle:

Actually, if you do want to support this feature from _Widget.connect(), you need to suspend/resume every element in the handles array, not just the last one.

Why is that? I suspend/resume the last handle and my code works fine. I can destroy the widget and recreate it and there doesn't appear to be any issues.

[bill]

Probably you didn't test keyboard.

[cb1kenobi]

I've been using this patch in my project and I love this feature. There's one scenario I hit that caused an issue though.

var link=dojo.connect(obj, "foo", obj, "bar");
...
function foo(){
    link.suspend(); // already disconnected
    ...
    link.resume(); // re-connects the event
}
...
link.suspend(); // disconnects the event
...
foo();
...
link.resume(); // re-connects the event again
...
dojo.disconnect(link);

Now the event is attached twice and that's no good.

I've uploaded a v2 of this patch that includes a flag to keep track of the suspended state. This fixed my issues and life is good.

[cb1kenobi]

Replying to bill:

Probably you didn't test keyboard.

I remember seeing that code, but this only is an issue if you _Widget.connect() to the "ondijitclick" event. In my case, I'm connecting to onchange of a select drop down and it works fine to grab the last handle.

[bill]

Ok... in that case is there more than one handle in the array?

[cb1kenobi]

Replying to bill:

Ok... in that case is there more than one handle in the array?

Sometimes yes, there is more than one handle, but it's not a big deal since I'm creating a local reference to the event like this:

postCreate: function(){
    var h = this.connect(this.myDropDown, "onchange", "_onChange");
    this._evt = h[h.length-1];
},
repopulateList: function(){
    this._evt.suspend();
    // code that clears and re-adds options to this.myDropDown goes here
    this._evt.resume();
}

[bill]

OK, well what I'm saying is that you need to suspend/resume all handles in the array. In the case where there is only one handle in the array, you are free to just suspend just "the last one", but of course that ends up being exactly the same thing.

[bill]

bump enhancements to next milestone, as we prepare to close out 1.2

[dante]

This keeps getting bumped. Maybe for 2.0? People have reportedly been using this patch for a while now?

[Chris Mitchell]

please review/triage

[bill]

Although not based on this patch, this was implemented in 1.7 with on.pausable, see ​http://livedocs.dojotoolkit.org/dojo/on#pausable-function.