org.eclipse.swt.layout
Class FormAttachment
java.lang.Object
org.eclipse.swt.layout.FormAttachment
-
public final class FormAttachment
- extends
Object
Instances of this class are used to define the edges of a control
within a FormLayout
.
FormAttachments
are set into the top, bottom, left,
and right fields of the FormData
for a control.
For example:
FormData data = new FormData();
data.top = new FormAttachment(0,5);
data.bottom = new FormAttachment(100,-5);
data.left = new FormAttachment(0,5);
data.right = new FormAttachment(100,-5);
button.setLayoutData(data);
A FormAttachment
defines where to attach the side of
a control by using the equation, y = ax + b. The "a" term represents
a fraction of the parent composite's width (from the left) or height
(from the top). It can be defined using a numerator and denominator,
or just a percentage value. If a percentage is used, the denominator
is set to 100. The "b" term in the equation represents an offset, in
pixels, from the attachment position. For example:
FormAttachment attach = new FormAttachment (20, -5);
specifies that the side to which the
FormAttachment
object belongs will lie at 20% of the parent composite, minus 5 pixels.
Control sides can also be attached to another control.
For example:
FormAttachment attach = new FormAttachment (button, 10);
specifies that the side to which the
FormAttachment
object belongs will lie in the same position as the adjacent side of
the
button
control, plus 10 pixels. The control side can
also be attached to the opposite side of the specified control.
For example:
FormData data = new FormData ();
data.left = new FormAttachment (button, 0, SWT.LEFT);
specifies that the left side of the control will lie in the same position
as the left side of the
button
control. The control can also
be attached in a position that will center the control on the specified
control. For example:
data.left = new FormAttachment (button, 0, SWT.CENTER);
specifies that the left side of the control will be positioned so that it is
centered between the left and right sides of the
button
control.
If the alignment is not specified, the default is to attach to the adjacent side.
-
Since:
- 2.0
-
See Also:
-
FormLayout
,
FormData
,
Sample code and further information
Field Summary
|
int
|
alignment
alignment specifies the alignment of the control side that is
attached to a control. |
Control
|
control
control specifies the control to which the control side is
attached. |
int
|
denominator
denominator specifies the denominator of the "a" term in the
equation, y = ax + b, which defines the attachment. |
int
|
numerator
numerator specifies the numerator of the "a" term in the
equation, y = ax + b, which defines the attachment. |
int
|
offset
offset specifies the offset, in pixels, of the control side
from the attachment position. |
Constructor Summary
|
FormAttachment
()
Constructs a new instance of this class. |
FormAttachment
(
Control control)
Constructs a new instance of this class given a control. |
FormAttachment
(
Control control,
int offset)
Constructs a new instance of this class given a control
and an offset. |
FormAttachment
(
Control control,
int offset,
int alignment)
Constructs a new instance of this class given a control,
an offset and an alignment. |
FormAttachment
(int numerator)
Constructs a new instance of this class given a numerator
Since no denominator or offset is specified, the default
is to treat the numerator as a percentage of the form, with a
denominator of 100. |
FormAttachment
(int numerator,
int offset)
Constructs a new instance of this class given a numerator
and an offset. |
FormAttachment
(int numerator,
int denominator,
int offset)
Constructs a new instance of this class given a numerator
and denominator and an offset. |
Method Summary
|
String
|
toString
()
Returns a string containing a concise, human-readable
description of the receiver. |
numerator
public int numerator
- numerator specifies the numerator of the "a" term in the
equation, y = ax + b, which defines the attachment.
denominator
public int denominator
- denominator specifies the denominator of the "a" term in the
equation, y = ax + b, which defines the attachment.
The default value is 100.
offset
public int offset
- offset specifies the offset, in pixels, of the control side
from the attachment position.
If the offset is positive, then the control side is offset
to the right of or below the attachment position. If it is
negative, then the control side is offset to the left of or
above the attachment position.
This is equivalent to the "b" term in the equation y = ax + b.
The default value is 0.
control
public
Control control
- control specifies the control to which the control side is
attached.
alignment
public int alignment
- alignment specifies the alignment of the control side that is
attached to a control.
For top and bottom attachments, TOP, BOTTOM and CENTER are used. For left
and right attachments, LEFT, RIGHT and CENTER are used. If any other case
occurs, the default will be used instead.
Possible values are:
-
SWT.TOP
: Attach the side to the top side of the specified control.
-
SWT.BOTTOM
: Attach the side to the bottom side of the specified control.
-
SWT.LEFT
: Attach the side to the left side of the specified control.
-
SWT.RIGHT
: Attach the side to the right side of the specified control.
-
SWT.CENTER
: Attach the side at a position which will center the control on the specified control.
-
SWT.DEFAULT
: Attach the side to the adjacent side of the specified control.
FormAttachment
public FormAttachment()
- Constructs a new instance of this class.
Since no numerator, denominator or offset is specified,
the attachment is treated as a percentage of the form.
The numerator is zero, the denominator is 100 and the
offset is zero.
-
Since:
- 3.2
FormAttachment
public FormAttachment(int numerator)
- Constructs a new instance of this class given a numerator
Since no denominator or offset is specified, the default
is to treat the numerator as a percentage of the form, with a
denominator of 100. The offset is zero.
-
Parameters:
-
numerator
- the percentage of the position -
Since:
- 3.0
FormAttachment
public FormAttachment(int numerator,
int offset)
- Constructs a new instance of this class given a numerator
and an offset. Since no denominator is specified, the default
is to treat the numerator as a percentage of the form, with a
denominator of 100.
-
Parameters:
-
numerator
- the percentage of the position -
offset
- the offset of the side from the position
FormAttachment
public FormAttachment(int numerator,
int denominator,
int offset)
- Constructs a new instance of this class given a numerator
and denominator and an offset. The position of the side is
given by the fraction of the form defined by the numerator
and denominator.
-
Parameters:
-
numerator
- the numerator of the position -
denominator
- the denominator of the position -
offset
- the offset of the side from the position
FormAttachment
public FormAttachment(
Control control)
- Constructs a new instance of this class given a control.
Since no alignment is specified, the default alignment is
to attach the side to the adjacent side of the specified
control. Since no offset is specified, an offset of 0 is
used.
-
Parameters:
-
control
- the control the side is attached to
FormAttachment
public FormAttachment(
Control control,
int offset)
- Constructs a new instance of this class given a control
and an offset. Since no alignment is specified, the default
alignment is to attach the side to the adjacent side of the
specified control.
-
Parameters:
-
control
- the control the side is attached to -
offset
- the offset of the side from the control
FormAttachment
public FormAttachment(
Control control,
int offset,
int alignment)
- Constructs a new instance of this class given a control,
an offset and an alignment. The possible alignment values are:
-
SWT.TOP
- the side will be attached to the top side of the specified control
-
SWT.BOTTOM
- the side will be attached to the bottom side of the specified control
-
SWT.LEFT
- the side will be attached to the left side of the specified control
-
SWT.RIGHT
- the side will be attached to the right side of the specified control
-
SWT.CENTER
- the side will be centered on the same side of the specified control
-
SWT.DEFAULT
- the side will be attached to the adjacent side of the specified control
-
Parameters:
-
control
- the control the side is attached to -
offset
- the offset of the side from the control -
alignment
- the alignment of the side to the control it is attached to,
one of TOP, BOTTOM, LEFT, RIGHT, CENTER, or DEFAULT
toString
public
String toString()
- Returns a string containing a concise, human-readable
description of the receiver.
-
-
Overrides:
-
toString
in class
Object
-
-
Returns:
- a string representation of the FormAttachment
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