From c413e16ff3e3b86e1914c5ebb13e4a6e1f1bfb29 Mon Sep 17 00:00:00 2001
From: Erik Lumme <erik@vaadin.com>
Date: Wed, 13 Sep 2017 10:51:21 +0300
Subject: Migrate MarkRequiredFieldsAsSuch

---
 .../articles/MarkRequiredFieldsAsSuch.asciidoc     | 40 ++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 documentation/articles/MarkRequiredFieldsAsSuch.asciidoc

(limited to 'documentation/articles/MarkRequiredFieldsAsSuch.asciidoc')

diff --git a/documentation/articles/MarkRequiredFieldsAsSuch.asciidoc b/documentation/articles/MarkRequiredFieldsAsSuch.asciidoc
new file mode 100644
index 0000000000..c80132db2c
--- /dev/null
+++ b/documentation/articles/MarkRequiredFieldsAsSuch.asciidoc
@@ -0,0 +1,40 @@
+[[mark-required-fields-as-such]]
+Mark required fields as such
+----------------------------
+
+Don’t make your users guess which fields in your form are required. Mark
+them as such:
+
+[source,java]
+....
+TextField tfFirstName = new TextField("First name");
+tfFirstName.setRequired(true);
+tfFirstName.setRequiredError("First name must be filled in!");
+....
+
+Required fields get a small *asterisk* after the caption (or after the
+field itself, if it doesn’t have a caption), which is quite universally
+understood to mean “required”. Of course, it certainly doesn’t hurt to
+have “footnote” somewhere in your form that explains it anyway.
+
+image:img/reqfield.png[Required field with asterisk]
+
+Marking a field as required also implicitly adds a non-empty validator
+to the field, preventing the form from being submitted unless a value
+has been entered. The error message associated with that validator can
+be set with the *setRequiredError()* method:
+
+[source,java]
+....
+TextField tfFirstName = new TextField("First name");
+tfFirstName.setRequired(true);
+tfFirstName.setRequiredError("First name must be filled in!");
+....
+
+image:img/errortooltip.png[Required field with error]
+
+Think carefully about which fields really are required, though. For
+instance, asking unnecessary questions in a sign-up form has a tendency
+to make people either cancel signing up, or enter nonsense information
+in fields they deem nonessential. Only mark as required fields that you
+really need the user to fill in, right there and then.
-- 
cgit v1.2.3

