Game Development Reference
In-Depth Information
GUI events and properties
To support events in the legacy GUI area, Unity added an entire event handler
specifically for GUI interactions. This class is aptly named the
Event
class.
Remember, this section refers to the legacy
GUI Event
classes,
which has nothing to do with the new
UnityEvent
system
introduced in the new
Unity UI
system. See
Chapter 6
,
Working with
the UI Source,
for more details of the
UnityEvent
system.
These events center on user and device input, varying from:
•
Event types
: Is it a key event, mouse event, and so on
•
Event values
: Which key pressed, mouse button pressed, and so on
•
Event summary information
: Modifier keys, mouse movement delta,
and so on
To access the events you simply need to query the
Event.current
property to get
the current
Event
state. (The
Event
state updates when there is a change, until then
you will get the last/previous state.)
The logon example earlier shows an example for using events, where we detect if
the user has pressed a key and if that key is the
Enter
key as shown in this script:
if (
Event.current.isKey
&&
Event.current.keyCode ==
KeyCode.Return &&
GUI.GetNameOfFocusedControl() == "PasswordField")
{
CheckUserPasswordAndRegister();
}
Along with the events, the GUI class also provides some additional properties you
can query or set in the
OnGUI
method, namely:
•
enabled
: Is the GUI enabled and displayed on the screen. Can it be used to
turn on or off controls that are to be drawn to the screen.
•
changed
: This returns true if any controls' values have changed since the last
call of
OnGUI
.
•
color
: This is the global color tint for the GUI layout.
•
contentColor
: This is the global text color tint for the GUI.
