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List:       openjdk-openjfx-dev
Subject:    Re: Allow input controls to indicate significant user interaction
From:       Michael_Strauß <michaelstrau2 () gmail ! com>
Date:       2023-03-27 17:58:41
Message-ID: CAJEpuXRi1-Z8Z9svGmW69+1ppJKW8AsokbB=ows1uG2war-V+w () mail ! gmail ! com
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I should add that aside from the javafx.scene.input.InputNode
interface, there is no addition to or modification of the core
platform.
Nothing in javaxf.graphics uses InputNode, it is provided solely as a
contract for the "significant interaction" information, which
third-party libraries can depend on without depending explicitly on
the javafx.controls module or any particular controls implementation.

On Mon, Mar 27, 2023 at 7:02 PM Kevin Rushforth
<kevin.rushforth@oracle.com> wrote:
> 
> I also am skeptical regarding the need for API in the core platform to support \
> this. 
> -- Kevin
> 
> 
> On 3/27/2023 9:46 AM, Andy Goryachev wrote:
> 
> I think this functionality belongs to the application-level code, not in the \
> platform.  It's the application that knows which parts of a form need the visual \
> feedback and which do not.  In my opinion, there is no APIs that are missing in \
> order to implement a validation framework of any level of complexity. 
> 
> 
> Not responding to programmatic changes is easy: disable validation logic when \
> setting values. 
> 
> 
> The validation and subsequent user feedback may happen at the time of form \
> submission, or as a result of a short timer expiring.  The timer should be \
> restarted upon each update of the value properties being validated. 
> 
> 
> In any case, this problem has a well-defined solution and, in my opinion, does not \
> require a change in the core platform. 
> 
> 
> Cheers,
> 
> -andy
> 
> 
> 
> 
> 
> From: openjfx-dev <openjfx-dev-retn@openjdk.org> on behalf of Michael Strauß \
>                 <michaelstrau2@gmail.com>
> Date: Sunday, March 26, 2023 at 17:49
> To: openjfx-dev <openjfx-dev@openjdk.org>
> Subject: Allow input controls to indicate significant user interaction
> 
> Many form-based applications require some sort of data validation for
> input controls. It is also often desirable to visualize the validation
> state of a control directly in the user interface, for example by
> showing a red border to indicate a validation failure.
> 
> However, simply validating the current value of a control and
> rendering a validation decorator often leads to an undesirable user
> experience: for example, in many cases an empty form field shouldn't
> indicate a validation failure unless the user has significantly
> interacted with the field, or validation was explicitly requested by
> pressing a "submit" button.
> 
> The first of these validation conditions, "significantly interacted
> with the input control" is quite popular on contemporary web forms,
> and offers a balanced user experience compared to immediately and
> eagerly validating every control, or delaying validation until the
> very end of the form submission process (see also the proposed
> > user-valid/:user-invalid CSS pseudo-classes).
> 
> Unfortunately, this is very hard to implement in JavaFX since controls
> have no way of signalling when they were significantly interacted
> with. In particular, we don't want to count programmatic
> initialization of field values as a significant interaction. What
> constitutes a significant interaction is dependent on the type of
> input control. For example, a text field might define a significant
> interaction as the sequence of gaining focus, receiving a new text
> value, and losing focus. A slider might define a significant
> interaction as the sequence of pressing the mouse button, dragging the
> slider thumb to a new value, and releasing the mouse button.
> 
> The information of how an input control changed its value is only
> really knowable by its skin and associated behavior classes, both of
> which are basically black boxes for a JavaFX application. In order to
> expose this information, I propose to add the following new interface
> in the "javafx.scene.input" package:
> 
> public interface InputNode {
> ReadOnlyBooleanProperty userModifiedProperty();
> boolean isUserModified();
> void setUserModified(boolean value);
> }
> 
> This interface identifies a node that can receive user input. It is
> implemented by the following controls: ButtonBase, ChoiceBox,
> ComboBoxBase, Slider, Spinner, and TextInputControl.
> 
> The associated skins and behaviors are modified to invoke
> setUserModified(true) on the control when a significant user
> interaction is detected. Once this flag is set on a control, it can
> only be unset programmatically from application code by invoking
> setUserModified(false).
> 
> You might note that userModifiedProperty() returns
> ReadOnlyBooleanProperty, while a public setter is availabe. The reason
> for this is that while applications should be able to set or clear the
> userModified flag programmatically, they shouldn't be able to bind the
> property to prevent it from being set by skins.
> 
> Note also that it is not a goal of this proposal to add a data
> validation framework to JavaFX (this is best left to third-party
> libraries instead). The goal is to expose a crucial piece of
> information that is not easily accessible otherwise.
> 
> I'm interested on your thoughts on this idea.
> 
> 


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