Wish Protect Sender from Sleep-walking killer

[Sandman]

In events we have Sender to inform us of the origin of the event. A magical companion that never is present in sub signatures, but always available once you learn about its mysterious ways. Or so I thought at least. Seems Sleep can kill it. (I haven't verified this, but it seems likely to also be vulnerable to the violent ways of Wait For.)

This wish originates from this thread

Sender not set in WebView_LocationChanged event

I have a layout with several WebViews, each containing html with a link. Clicking a link triggers the LocationChanged event just fine. However, I can't figure out how to get which WebView the click happened in, as Sender is Null. Is this expected behaviour on B4J or have I misunderstood...

www.b4x.com

My wish is something like this...

1. Make Sender available even after Sleep (and Wait For etc)

or

2. Make the IDE linter detect usage of Sender after Sleep and say something like "Warning: Sender is Null after Sleep and Wait For"

or

3. At the very least put the information in the hover-documentation for Sender and also in the forum when one searches for Sender:

 

[Erel]

I'll start with option 3

 

[Sandman]

That was my guess.

 

[Erel]

Option 1 is possible but requires saving the sender value in all resumable subs instances. Too much overhead for the benefit.
Option 2 is of course helpful and might be added at some point. Not trivial (but also not dramatic).
Option 3 is the low hanging fruit.

 

[Sandman]

Yeah, that's pretty much exactly how I envisioned the difficulty. Doesn't hurt to ask though, and just getting it out of the darkness and into the bright light of documentation solves it Good Enough(tm).

Let's be honest, I kind of feel like I stumbled in an edge-case here. Not too many will experience it.

By the way, I put that Sleep in there because I copied it from one of your code examples, on how to stop the loading of a clicked link.

 

[aeric]

Interesting finding. Thanks for sharing. ?

 

[Cableguy]

I may be wrong, I usually am, but my work around for this, assuming the sender is of known type, recast it to a sub local view...

 

[Sandman]

my work around for this, assuming the sender is of known type, recast it to a sub local view

Yep, as linked in #1:

Sender not set in WebView_LocationChanged event

I have a layout with several WebViews, each containing html with a link. Clicking a link triggers the LocationChanged event just fine. However, I can't figure out how to get which WebView the click happened in, as Sender is Null. Is this expected behaviour on B4J or have I misunderstood...

www.b4x.com

 

[Cableguy]

Why not use the tag prop as an identifier ?

 

[Sandman]

Why not use the tag prop as an identifier ?

If you really want to discuss this, move it into Chit Chat so we don't get this wish thread off the rails.

 

[Cableguy]

If you really want to discuss this, move it into Chit Chat so we don't get this wish thread off the rails.

No need... I understand the wish, and what caused it.. I was just pointing how I would workaround it