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public
abstract
class
Shape
extends Object
implements
Cloneable
java.lang.Object | |
↳ | android.graphics.drawable.shapes.Shape |
Defines a generic graphical "shape."
Any Shape can be drawn to a Canvas with its own draw() method, but more
graphical control is available if you instead pass it to a
ShapeDrawable
.
Custom Shape classes must implement clone()
and return an instance
of the custom Shape class.
Public constructors | |
---|---|
Shape()
|
Public methods | |
---|---|
Shape
|
clone()
Creates and returns a copy of this object. |
abstract
void
|
draw(Canvas canvas, Paint paint)
Draws this shape into the provided Canvas, with the provided Paint. |
boolean
|
equals(Object o)
Indicates whether some other object is "equal to" this one. |
final
float
|
getHeight()
Returns the height of the Shape. |
void
|
getOutline(Outline outline)
Computes the Outline of the shape and return it in the supplied Outline parameter. |
final
float
|
getWidth()
Returns the width of the Shape. |
boolean
|
hasAlpha()
Checks whether the Shape is opaque. |
int
|
hashCode()
Returns a hash code value for the object. |
final
void
|
resize(float width, float height)
Resizes the dimensions of this shape. |
Protected methods | |
---|---|
void
|
onResize(float width, float height)
Callback method called when |
Inherited methods | |
---|---|
public Shape ()
public Shape clone ()
Creates and returns a copy of this object. The precise meaning
of "copy" may depend on the class of the object. The general
intent is that, for any object x
, the expression:
will be true, and that the expression:x.clone() != x
will bex.clone().getClass() == x.getClass()
true
, but these are not absolute requirements.
While it is typically the case that:
will bex.clone().equals(x)
true
, this is not an absolute requirement.
By convention, the returned object should be obtained by calling
super.clone
. If a class and all of its superclasses (except
Object
) obey this convention, it will be the case that
x.clone().getClass() == x.getClass()
.
By convention, the object returned by this method should be independent
of this object (which is being cloned). To achieve this independence,
it may be necessary to modify one or more fields of the object returned
by super.clone
before returning it. Typically, this means
copying any mutable objects that comprise the internal "deep structure"
of the object being cloned and replacing the references to these
objects with references to the copies. If a class contains only
primitive fields or references to immutable objects, then it is usually
the case that no fields in the object returned by super.clone
need to be modified.
The method clone
for class Object
performs a
specific cloning operation. First, if the class of this object does
not implement the interface Cloneable
, then a
CloneNotSupportedException
is thrown. Note that all arrays
are considered to implement the interface Cloneable
and that
the return type of the clone
method of an array type T[]
is T[]
where T is any reference or primitive type.
Otherwise, this method creates a new instance of the class of this
object and initializes all its fields with exactly the contents of
the corresponding fields of this object, as if by assignment; the
contents of the fields are not themselves cloned. Thus, this method
performs a "shallow copy" of this object, not a "deep copy" operation.
The class Object
does not itself implement the interface
Cloneable
, so calling the clone
method on an object
whose class is Object
will result in throwing an
exception at run time.
Returns | |
---|---|
Shape |
a clone of this instance. |
Throws | |
---|---|
CloneNotSupportedException |
public abstract void draw (Canvas canvas, Paint paint)
Draws this shape into the provided Canvas, with the provided Paint.
Before calling this, you must call resize(float, float)
.
Parameters | |
---|---|
canvas |
Canvas : the Canvas within which this shape should be drawn |
paint |
Paint : the Paint object that defines this shape's characteristics |
public boolean equals (Object o)
Indicates whether some other object is "equal to" this one.
The equals
method implements an equivalence relation
on non-null object references:
x
, x.equals(x)
should return
true
.
x
and y
, x.equals(y)
should return true
if and only if
y.equals(x)
returns true
.
x
, y
, and z
, if
x.equals(y)
returns true
and
y.equals(z)
returns true
, then
x.equals(z)
should return true
.
x
and y
, multiple invocations of
x.equals(y)
consistently return true
or consistently return false
, provided no
information used in equals
comparisons on the
objects is modified.
x
,
x.equals(null)
should return false
.
The equals
method for class Object
implements
the most discriminating possible equivalence relation on objects;
that is, for any non-null reference values x
and
y
, this method returns true
if and only
if x
and y
refer to the same object
(x == y
has the value true
).
Note that it is generally necessary to override the hashCode
method whenever this method is overridden, so as to maintain the
general contract for the hashCode
method, which states
that equal objects must have equal hash codes.
Parameters | |
---|---|
o |
Object : the reference object with which to compare. |
Returns | |
---|---|
boolean |
true if this object is the same as the obj
argument; false otherwise. |
public final float getHeight ()
Returns the height of the Shape.
Returns | |
---|---|
float |
public void getOutline (Outline outline)
Computes the Outline of the shape and return it in the supplied Outline
parameter. The default implementation does nothing and outline
is not changed.
Parameters | |
---|---|
outline |
Outline : the Outline to be populated with the result. Must be
non-null .
This value cannot be null . |
public final float getWidth ()
Returns the width of the Shape.
Returns | |
---|---|
float |
public boolean hasAlpha ()
Checks whether the Shape is opaque.
Default impl returns true
. Override if your subclass can be
opaque.
Returns | |
---|---|
boolean |
true if any part of the drawable is not opaque. |
public int hashCode ()
Returns a hash code value for the object. This method is
supported for the benefit of hash tables such as those provided by
HashMap
.
The general contract of hashCode
is:
hashCode
method
must consistently return the same integer, provided no information
used in equals
comparisons on the object is modified.
This integer need not remain consistent from one execution of an
application to another execution of the same application.
equals(Object)
method, then calling the hashCode
method on each of
the two objects must produce the same integer result.
equals(java.lang.Object)
method, then calling the hashCode
method on each of the
two objects must produce distinct integer results. However, the
programmer should be aware that producing distinct integer results
for unequal objects may improve the performance of hash tables.
As much as is reasonably practical, the hashCode method defined by
class Object
does return distinct integers for distinct
objects. (This is typically implemented by converting the internal
address of the object into an integer, but this implementation
technique is not required by the
Java™ programming language.)
Returns | |
---|---|
int |
a hash code value for this object. |
public final void resize (float width, float height)
Resizes the dimensions of this shape.
Must be called before draw(android.graphics.Canvas, android.graphics.Paint)
.
Parameters | |
---|---|
width |
float : the width of the shape (in pixels) |
height |
float : the height of the shape (in pixels) |
protected void onResize (float width, float height)
Callback method called when resize(float, float)
is executed.
Parameters | |
---|---|
width |
float : the new width of the Shape |
height |
float : the new height of the Shape |