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[[visually-distinguish-primary-actions]]
Visually distinguish primary actions
------------------------------------
Most forms and dialogs have at least two actions that can be performed,
such as _Submit/Cancel_, _Save/Revert_ or _Yes/No_. Quite often, there
are more, such as a login form with the actions _“Sign in”_,
_“Register”_, and _“Forgot password”_. Usually, one of these actions is
by far the most commonly used, and as such, the most likely one the user
is going to be looking for.
If all actions are represented by identical buttons (save for the
caption), identifying the primary button can be quite slow, and the risk
of selecting the wrong action by mistake (especially when in a hurry) is
substantial:
image:img/sign%20in%20-%20no%20distinction.png[Sign in - no distinction]
By visually distinguishing primary actions, e.g. by color, size or
shape, the user can quickly and accurately find them even in a crowded,
cluttered UI. A typical approach is to use a stronger (more saturated)
color with greater contrast for the primary actions, and a grayer, lower
contrast color for the secondary actions:
image:img/sign%20in%20-%20primary%20distinguished.png[Sign in - distinguished]
Sometimes a view can have more than one primary action simultaneously
available, although usually in different parts of the view. Google
handles this quite elegantly by systematically styling _creation_
primary buttons (such as _Compose_ in Gmail and _Create_ in Drive) in
*red*, and other primary buttons (such as search) in *blue*, while
leaving secondary buttons *gray*:
image:img/google%20drive.png[Google drive]
Choose colors wisely, though – red, for instance, means _“no”_, _"stop"_
or _“danger”_ in most cultures, so using that for _“Yes”_ or _“Submit”_
might send the user mixed signals. You might also want to take into
account the effects of color blindness (affecting approximately 10% of
men and 1% of women), especially if your user base is going to be tens
of thousands of people.
Setting a different visual style for primary action buttons is very easy
to do in Vaadin by using the *BUTTON_DEFAULT* stylename in any of the
built-in themes like Reindeer or Chameleon:
[source,java]
....
Button btnSignIn = new Button("Sign in");
btnSignIn.addStyleName(Reindeer.BUTTON_DEFAULT);
....
Another common approach, mainly used on the web, is to use text links
instead of buttons for secondary or tertiary actions. This has a
significantly stronger effect than color or size, and should only be
used for significantly less common actions, such as a password reset
request, not for the _“No”_ option in a _Yes/No_ dialog, for instance:
image:img/sign%20in%20-%20all%20different.png[Sign in - all different]
This is just as easy in Vaadin. Just use the *BUTTON_LINK* stylename
defined in the base theme (and inherited in all built in themes), and
your Button will look like a normal text-hyperlink.
[source,java]
....
Button btnForgotPwd = new Button("Forgot password?");
btnForgotPwd.addStyleName(Reindeer.BUTTON_LINK);
....
(Note that the separate *Link* component should not be used for server
actions, since you can't bind a ClickListener to a Link.)
[[consider-binding-the-enter-key-to-the-primary-action]]
Consider binding the Enter key to the primary action
++++++++++++++++++++++++++++++++++++++++++++++++++++
Especially in short, often used forms, such as a login form, it is
usually a good idea to bind the Enter key to the primary action. This
relieves the user from having to move his hand from the keyboard to the
mouse.
[source,java]
....
Button btnSignIn = new Button("Sign in");
btnSignIn.addStyleName(Reindeer.BUTTON_DEFAULT);
btnSignIn.setClickShortcut(KeyCode.ENTER);
....
If the primary action is something that really mustn’t be invoked by
mistake or without properly thinking about it first, however, it’s
probably better not to bind it to a keyboard shortcut, to avoid
accidental invocations. Another reason to abstain from a keyboard
shortcut is if the form contains an input field in which Enter can be
used for something, such as a multi-line text area (where Enter creates
a line break).
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