[T5.1]Add a field specific error message using beforeLabel

[Thomas Cucchietti]

Hi everybody!

I'm facing a problem I can't resolve, even after hours of reflexion and
tests so I'm asking for help :)

Here is my need : I would like to display the error message corresponding to
each field of my form just above the label of this field.

I've made some research and have found a very interesting post of Thiago
about custom ValidationDecorator.

I created mine, added it to my AppModule and everything should be ok.

Here is the specific part of my ValidationDecorator :

    @Override
    public void beforeLabel(Field field) {
        if (inError(field)) {
            markupWriter.element("div",
                    "class", "single-error-message");
            ValidationTracker tracker =
environment.peekRequired(ValidationTracker.class);
            markupWriter.write(tracker.getError(field));
            markupWriter.end();

        }
    }

The problem is that, for a field in error (i.e. required field that is
empty), when the label renders itself and call the beforeLabel() method, the
field is not considered as in error (inError(field) returns false).

I've checked and in the insideLabel() method, the field is in error but it's
too late to use markupwriter as the label is already rendered.

Finally I tried to manipulate DOM but it doesn't work too... (I'll
eventually post the corresponding code later but it's not the main point of
this mail).

So my question is : is there a way to recognize that the field is in error
in the beforeLabel() method?

Thanks in advance for help!

Thomas