Shape
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.
Summary
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 constructors
Shape
public Shape ()
Public methods
clone
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 be x.clone().getClass() == x.getClass()
true
, but these are not absolute requirements.
While it is typically the case that:
will be x.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.
Returns | |
---|---|
Shape |
a clone of this instance. |
Throws | |
---|---|
CloneNotSupportedException |
draw
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 |
equals
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:
- It is reflexive: for any non-null reference value
x
,x.equals(x)
should returntrue
. - It is symmetric: for any non-null reference values
x
andy
,x.equals(y)
should returntrue
if and only ify.equals(x)
returnstrue
. - It is transitive: for any non-null reference values
x
,y
, andz
, ifx.equals(y)
returnstrue
andy.equals(z)
returnstrue
, thenx.equals(z)
should returntrue
. - It is consistent: for any non-null reference values
x
andy
, multiple invocations ofx.equals(y)
consistently returntrue
or consistently returnfalse
, provided no information used inequals
comparisons on the objects is modified. - For any non-null reference value
x
,x.equals(null)
should returnfalse
.
An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.
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. |
getHeight
public final float getHeight ()
Returns the height of the Shape.
Returns | |
---|---|
float |
getOutline
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 . |
getWidth
public final float getWidth ()
Returns the width of the Shape.
Returns | |
---|---|
float |
hasAlpha
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. |
hashCode
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:
- Whenever it is invoked on the same object more than once during
an execution of a Java application, the
hashCode
method must consistently return the same integer, provided no information used inequals
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. - If two objects are equal according to the
equals
method, then calling thehashCode
method on each of the two objects must produce the same integer result. - It is not required that if two objects are unequal
according to the
equals
method, then calling thehashCode
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.
Returns | |
---|---|
int |
a hash code value for this object. |
resize
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 methods
onResize
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 |