question regarding dialog dismiss/cancel handling

by Jason Proctor » Fri, 20 Nov 2009 10:00:39 GMT


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 i never look forward to handling Android dialogs, maybe someone can 
point me to a better way of doing it than i'm doing right now.

say i have a dialog which has one text field in it, and OK and Cancel 
buttons. i make the dialog with AlertDialog.Builder, and set click 
listeners on the buttons and dismiss listener on the dialog.

when the dismiss listener fires, can i tell which button caused the 
dismiss? i don't see how, so in the click listener, i set a member 
flag according to which button was clicked. then in the dismiss 
listener, i then check the flag to see whether to proceed or not. a 
rather backward process. am i missing something?

the other issue i have with Android's dialogs is that if the contents 
fail validation and the dialog needs to be re-presented, i have to 
re-show it in the dismiss listener. in every other environment known 
to man, dialogs are (somewhat) modal, so the dialog stays up unless 
expressly dismissed by code. IMHO, the latter makes more sense.

thanks for any help with this stuff,
-- 
jason.vp.engineering.particle

--



question regarding dialog dismiss/cancel handling

by TreKing » Fri, 20 Nov 2009 11:50:59 GMT


 "when the dismiss listener fires, can i tell which button caused
the dismiss?"

No - I don't think any of the buttons by default cause the dialog to be
dismissed. This happens when you call dismiss() or cancel() on the dialog or
the user presses the back button.

"so in the click listener, i set a member flag according to which button was
clicked. then in the dismiss listener, i then check the flag to see whether
to proceed or not"

But you have set on click listeners for each of the two buttons you have,
no? So why not handle their actions in their respective click listeners?
What are you doing in each of those listeners (I'm going to bet you're
dismissing the dialog after storing the flag...)?

"the other issue i have with Android's dialogs is that if the contents fail
validation and the dialog needs to be re-presented, i have to re-show it in
the dismiss listener"

No, you don't have to do this. In your listener for the OK button you can
get the text field, validate it, and if it fails show a toast message, and
don't dismiss the dialog. If it succeeds, do what you need to with the
entered data and THEN call dismiss() on the dialog.

If you want to get fancy you can also validate the user data as they type
and disable and enable the OK button in response so they can only hit OK
when they've entered valid data.

Also, I highly doubt you need the dismiss listener in your case. Hope that
helps.

-------------------------------------------------------------------------------------------------
TreKing - Chicago transit tracking app for Android-powered devices
 http://sites.google.com/site/rezmobileapps/treking 

On Thu, Nov 19, 2009 at 8:00 PM, Jason Proctor <



>


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question regarding dialog dismiss/cancel handling

by Jason Proctor » Sat, 21 Nov 2009 03:20:39 GMT


 hanks for the response, most helpful.

i don't actively dismiss the dialog at any point, therefore something
behind the button click must be doing it. i took a look in
android.internal.app.AlertController.java, and found that its click
listener calls the appropriate button handler, then sends a dismiss
message to the dialog. unless i'm missing something big, seems fairly
conclusive.

so the reasons why i do it this convoluted way are coming back to me.
due to the auto-dismiss, i have to validate in the dismiss handler,
as i can't schedule a reappearance of the dialog in the onClick().

i suppose i'll have to get all fancy and do the validation key by key, then.

(the point remains that Android has the weirdest modal dialog
handling of any environment i've encountered!)

thanks,
J


>



question regarding dialog dismiss/cancel handling

by TreKing » Sat, 21 Nov 2009 03:45:48 GMT


 ust ran a quick test on my code and you're right! Sorry for the wrong info.
I've been manually calling dismiss() and cancel() on the dialogs I use. It's
been a while since I looked at that code and figured I was doing that
because I had to ... now this makes me wonder why I did it that way to begin
with =P.

But you should still be able to do validation on the OK button being
clicked, and if that fails, just re-show the dialog.

"as i can't schedule a reappearance of the dialog in the onClick()"

Why not? If you define your click handler inline within the activity that's
using it, you can just call showDialog(ID) in onClick(), no?
Or does that not work?

-------------------------------------------------------------------------------------------------
TreKing - Chicago transit tracking app for Android-powered devices
http://sites.google.com/site/rezmobileapps/treking


On Fri, Nov 20, 2009 at 1:20 PM, Jason Proctor <
jason.android.li...@gmail.com> wrote:

> >



question regarding dialog dismiss/cancel handling

by Jason Proctor » Sat, 21 Nov 2009 03:49:57 GMT


 an't re-show the dialog in onClick(), because it's already shown. at 
least that was true with 1.1, i should check it with a later SDK.

so either i do my validation in onDismiss(), or i get all fancy.


>>



question regarding dialog dismiss/cancel handling

by TreKing » Sat, 21 Nov 2009 04:11:41 GMT


 hat if you call setCancelable(false) on the dialog? Will it still
auto-dismiss?

I would assume not and then you could do what you're trying to do and call
cancel() manually when you're done validating.

-------------------------------------------------------------------------------------------------
TreKing - Chicago transit tracking app for Android-powered devices
http://sites.google.com/site/rezmobileapps/treking


On Fri, Nov 20, 2009 at 1:49 PM, Jason Proctor <
jason.android.li...@gmail.com> wrote:

> >>



question regarding dialog dismiss/cancel handling

by Brad Gies » Sat, 21 Nov 2009 04:11:47 GMT


 ou can definitely post a message to a handler in the OnClick and then 
show the dialog again when your Handler gets the message...




Jason Proctor wrote:
>>>



question regarding dialog dismiss/cancel handling

by Jason Proctor » Sat, 21 Nov 2009 04:24:50 GMT


 ccording to the docs, setCancelable() determines whether the "back" 
key cancels the dialog.

it's not so much the cancel behaviour as the ok behaviour. if the
dialog didn't auto-dismiss on an OK click, then things would work a
lot easier.

well, i'm just going to write a wrapper class that does all this dumb
stuff and calls out to custom validator and acceptor listeners to do
the necessary. it's a bit odd that Android has listeners up the wazoo
but Dialog doesn't quite fit in.



>>>



question regarding dialog dismiss/cancel handling

by TreKing » Sat, 21 Nov 2009 04:43:39 GMT


 eah, just ran a quick test and setting cancelable to false stills lets the
dialog be dismissed by a button press. Weird. This definitely feels
ass-backwards.

Well, the last thing I can think of is adding your own layout with an OK and
cancel button with Dialog.setView() and handle the clicking on THOSE the way
you wanted to. That should definitely work. And it might be less work than a
full-blown wrapper.

Good luck!

-------------------------------------------------------------------------------------------------
TreKing - Chicago transit tracking app for Android-powered devices
http://sites.google.com/site/rezmobileapps/treking


On Fri, Nov 20, 2009 at 2:24 PM, Jason Proctor <
jason.android.li...@gmail.com> wrote:

> >>>



question regarding dialog dismiss/cancel handling

by Jason Proctor » Sat, 21 Nov 2009 04:55:00 GMT


 ell i already did the wrapper so :-)

thanks for your help on this one...



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