A
Frame
is a top-level window with a title and a border.
The size of the frame includes any area designated for the
border. The dimensions of the border area may be obtained
using the getInsets
method, however, since
these dimensions are platform-dependent, a valid insets
value cannot be obtained until the frame is made displayable
by either calling pack
or show
.
Since the border area is included in the overall size of the
frame, the border effectively obscures a portion of the frame,
constraining the area available for rendering and/or displaying
subcomponents to the rectangle which has an upper-left corner
location of (insets.left, insets.top)
, and has a size of
width - (insets.left + insets.right)
by
height - (insets.top + insets.bottom)
.
The default layout for a frame is BorderLayout
.
A frame may have its native decorations (i.e. Frame
and Titlebar
) turned off
with setUndecorated
. This can only be done while the frame
is not displayable
.
In a multi-screen environment, you can create a Frame
on a different screen device by constructing the Frame
with Frame.Frame(GraphicsConfiguration)
or
Frame.Frame(String title, GraphicsConfiguration)
. The
GraphicsConfiguration
object is one of the
GraphicsConfiguration
objects of the target screen
device.
In a virtual device multi-screen environment in which the desktop
area could span multiple physical screen devices, the bounds of all
configurations are relative to the virtual-coordinate system. The
origin of the virtual-coordinate system is at the upper left-hand
corner of the primary physical screen. Depending on the location
of the primary screen in the virtual device, negative coordinates
are possible, as shown in the following figure.
In such an environment, when calling setLocation
,
you must pass a virtual coordinate to this method. Similarly,
calling getLocationOnScreen
on a Frame
returns virtual device coordinates. Call the getBounds
method of a GraphicsConfiguration
to find its origin in
the virtual coordinate system.
The following code sets the
location of the Frame
at (10, 10) relative
to the origin of the physical screen of the corresponding
GraphicsConfiguration
. If the bounds of the
GraphicsConfiguration
is not taken into account, the
Frame
location would be set at (10, 10) relative to the
virtual-coordinate system and would appear on the primary physical
screen, which might be different from the physical screen of the
specified GraphicsConfiguration
.
Frame f = new Frame(GraphicsConfiguration gc);
Rectangle bounds = gc.getBounds();
f.setLocation(10 + bounds.x, 10 + bounds.y);
Frames are capable of generating the following types of
WindowEvent
s:
WINDOW_OPENED
WINDOW_CLOSING
:
If the program doesn't
explicitly hide or dispose the window while processing
this event, the window close operation is canceled.
WINDOW_CLOSED
WINDOW_ICONIFIED
WINDOW_DEICONIFIED
WINDOW_ACTIVATED
WINDOW_DEACTIVATED
WINDOW_GAINED_FOCUS
WINDOW_LOST_FOCUS
WINDOW_STATE_CHANGED