Only regiter listener for selectionchange on IOS

[Jenselme]

I have a strange problem with slip on chrome, IE and firefox with the dom.select_events.enabled set to true (as describe here): the onSelection callback is fired before the holdTimer can complete. That prevent the reordering to work. To get it working, I have to first click on on the draggable element and only then reorder. Here are examples of this:

• example with the problem: In order to reorder of the selected maps on Chrome or IE, you need to first click on a map.
• example with this patch: you can reorder the maps right away.

From what I understand of the comment, this listener is only relevant for ios devices, so it shouldn't have an impact on other platforms. Strangely, your demo is not affected by this.

[kornelski]

Is there a solution that does not involve detecting a particular browser? Is that a timing issue? Can it be solved by setting a flag or deferring actions with setTimeout?

[Jenselme]

Can it be solved by setting a flag or deferring actions with setTimeout?

I think I could set a flag in setTimeout and use it not to execute the function associated with the selectionchange event. If I didn't use this solution, it was to interfere as little as possible with a function I don't fully understand the purpose. I tried to just remove the line, and everything looked fine (not tested on iOS though).

Do you prefer the flag approach? I understand that checking the user agent is not really a reliable way to detect a browser.

[kornelski]

Listening for selection change event (and preventDefault on it) is to prevent mouse movement during reordering from being interpreted as text selection gesture. Without it drag may still work, but browsers will be selecting all text along the way, which is ugly and confusing.

The second problem is that on iOS you can't prevent selection this way (you can with CSS only), but you can at least react to it happening, so Slip tries to cooperate with iOS in that case, and aborts the drag.

Does this line run in your case? (i.e. if you delete that line, does it work for you?) https://github.com/pornel/slip/blob/4fa9d23063e5b88e31850ae57dc5303daa48ba65/slip.js#L583

if so, it'd be better to add browser sniffing to this condition https://github.com/pornel/slip/blob/master/slip.js#L577

[Jenselme]

Listening for selection change event (and preventDefault on it) is to prevent mouse movement during reordering from being interpreted as text selection gesture. Without it drag may still work, but browsers will be selecting all text along the way, which is ugly and confusing.

Agreed.

Does this line run in your case? (i.e. if you delete that line, does it work for you?) https://github.com/pornel/slip/blob/4fa9d23063e5b88e31850ae57dc5303daa48ba65/slip.js#L583

It does.

if so, it'd be better to add browser sniffing to this condition

I'm fine with that since it will solve my problem. Do you have a reliable way to detect iOS?

[kornelski]

Do you have a reliable way to detect iOS?

No, unfortunately. Test for iPhone|iPad|iPod and not Android|Windows (to eliminate some everything-goes user-agents).

[Jenselme]

Just updated the PR.

[kornelski]

Thanks