| java.lang.Object | |
| ↳ | android.graphics.drawable.Drawable |
 Known Direct Subclasses
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Known Indirect Subclasses
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A Drawable is a general abstraction for "something that can be drawn." Most
often you will deal with Drawable as the type of resource retrieved for
drawing things to the screen; the Drawable class provides a generic API for
dealing with an underlying visual resource that may take a variety of forms.
Unlike a View, a Drawable does not have any facility to
receive events or otherwise interact with the user.
In addition to simple drawing, Drawable provides a number of generic mechanisms for its client to interact with what is being drawn:
setBounds(Rect) method must be called to tell the
Drawable where it is drawn and how large it should be. All Drawables
should respect the requested size, often simply by scaling their
imagery. A client can find the preferred size for some Drawables with
the getIntrinsicHeight() and getIntrinsicWidth() methods.
getPadding(Rect) method can return from some Drawables
information about how to frame content that is placed inside of them.
For example, a Drawable that is intended to be the frame for a button
widget would need to return padding that correctly places the label
inside of itself.
setState(int[]) method allows the client to tell the Drawable
in which state it is to be drawn, such as "focused", "selected", etc.
Some drawables may modify their imagery based on the selected state.
setLevel(int) method allows the client to supply a single
continuous controller that can modify the Drawable is displayed, such as
a battery level or progress level. Some drawables may modify their
imagery based on the current level.
Drawable.Callback interface. All clients should support this
interface (via setCallback(Drawable.Callback)) so that animations will work. A
simple way to do this is through the system facilities such as
setBackgroundDrawable(Drawable) and
ImageView.
For more information about how to use drawables, read the Canvas and Drawables developer guide. For information and examples of creating drawable resources (XML or bitmap files that can be loaded in code), read the Drawable Resources document.
| Nested Classes | |||||||||||
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| Drawable.Callback | Implement this interface if you want to create an animated drawable that
extends Drawable. |
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| Drawable.ConstantState | This abstract class is used by Drawables to store shared constant state and data
between Drawables. |
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| Public Constructors | |||||||||||
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| Public Methods | |||||||||||
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Return a copy of the drawable's bounds in a new Rect.
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Return a copy of the drawable's bounds in the specified Rect (allocated
by the caller).
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Create a drawable from file path name.
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Create a drawable from an inputstream, using the given resources and
value to determine density information.
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Create a drawable from an inputstream, using the given resources and
value to determine density information.
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Create a drawable from an inputstream
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Create a drawable from an XML document.
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Create from inside an XML document.
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Draw in its bounds (set via setBounds) respecting optional effects such
as alpha (set via setAlpha) and color filter (set via setColorFilter).
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Gets the current alpha value for the drawable.
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Return the drawable's bounds Rect.
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Return the current
Drawable.Callback implementation attached to this
Drawable. | |||||||||||
Return a mask of the configuration parameters for which this drawable
may change, requiring that it be re-created.
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Return a
Drawable.ConstantState instance that holds the shared state of this Drawable. | |||||||||||
Return the intrinsic height of the underlying drawable object.
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Return the intrinsic width of the underlying drawable object.
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Retrieve the current level.
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Returns the minimum height suggested by this Drawable.
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Returns the minimum width suggested by this Drawable.
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Return the opacity/transparency of this Drawable.
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Return in padding the insets suggested by this Drawable for placing
content inside the drawable's bounds.
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Describes the current state, as a union of primitve states, such as
state_focused,
state_selected, etc. | |||||||||||
Returns a Region representing the part of the Drawable that is completely
transparent.
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Inflate this Drawable from an XML resource.
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Use the current
Drawable.Callback implementation to have this Drawable
redrawn. | |||||||||||
Tells if this Drawable will be automatically mirrored when its layout direction is RTL
right-to-left.
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Indicates whether this view will change its appearance based on state.
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If this Drawable does transition animations between states, ask that
it immediately jump to the current state and skip any active animations.
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Make this drawable mutable.
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Return the appropriate opacity value for two source opacities.
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Use the current
Drawable.Callback implementation to have this Drawable
scheduled. | |||||||||||
Specify an alpha value for the drawable.
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Set whether this Drawable is automatically mirrored when its layout direction is RTL
(right-to left).
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Specify a bounding rectangle for the Drawable.
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Specify a bounding rectangle for the Drawable.
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Bind a
Drawable.Callback object to this Drawable. | |||||||||||
Set a mask of the configuration parameters for which this drawable
may change, requiring that it be re-created.
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Specify an optional colorFilter for the drawable.
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Specify a color and porterduff mode to be the colorfilter for this
drawable.
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Set to true to have the drawable dither its colors when drawn to a device
with fewer than 8-bits per color component.
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Set to true to have the drawable filter its bitmap when scaled or rotated
(for drawables that use bitmaps).
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Specify the level for the drawable.
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Specify a set of states for the drawable.
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Set whether this Drawable is visible.
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Use the current
Drawable.Callback implementation to have this Drawable
unscheduled. | |||||||||||
| Protected Methods | |||||||||||
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Override this in your subclass to change appearance if you recognize the
specified state.
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Override this in your subclass to change appearance if you vary based
on level.
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Override this in your subclass to change appearance if you recognize the
specified state.
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[Expand]
Inherited Methods | |||||||||||
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From class
java.lang.Object
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Return a copy of the drawable's bounds in a new Rect. This returns the same values as getBounds(), but the returned object is guaranteed to not be changed later by the drawable (i.e. it retains no reference to this rect). If the caller already has a Rect allocated, call copyBounds(rect).
Return a copy of the drawable's bounds in the specified Rect (allocated by the caller). The bounds specify where this will draw when its draw() method is called.
| bounds | Rect to receive the drawable's bounds (allocated by the caller). |
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Create a drawable from file path name.
Create a drawable from an inputstream, using the given resources and value to determine density information.
Create a drawable from an inputstream, using the given resources and value to determine density information.
Create a drawable from an inputstream
Create a drawable from an XML document. For more information on how to create resources in XML, see Drawable Resources.
Create from inside an XML document. Called on a parser positioned at a tag in an XML document, tries to create a Drawable from that tag. Returns null if the tag is not a valid drawable.
Draw in its bounds (set via setBounds) respecting optional effects such as alpha (set via setAlpha) and color filter (set via setColorFilter).
| canvas | The canvas to draw into |
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Gets the current alpha value for the drawable. 0 means fully transparent, 255 means fully opaque. This method is implemented by Drawable subclasses and the value returned is specific to how that class treats alpha. The default return value is 255 if the class does not override this method to return a value specific to its use of alpha.
Return the drawable's bounds Rect. Note: for efficiency, the returned object may be the same object stored in the drawable (though this is not guaranteed), so if a persistent copy of the bounds is needed, call copyBounds(rect) instead. You should also not change the object returned by this method as it may be the same object stored in the drawable.
Return the current Drawable.Callback implementation attached to this
Drawable.
Drawable.Callback instance or null if no callback was set.Return a mask of the configuration parameters for which this drawable
may change, requiring that it be re-created. The default implementation
returns whatever was provided through
setChangingConfigurations(int) or 0 by default. Subclasses
may extend this to or in the changing configurations of any other
drawables they hold.
Configuration.Return a Drawable.ConstantState instance that holds the shared state of this Drawable.
q
StateListDrawable and LevelListDrawable this will be the child drawable
currently in use.
Return the intrinsic height of the underlying drawable object. Returns -1 if it has no intrinsic height, such as with a solid color.
Return the intrinsic width of the underlying drawable object. Returns -1 if it has no intrinsic width, such as with a solid color.
Retrieve the current level.
Returns the minimum height suggested by this Drawable. If a View uses this Drawable as a background, it is suggested that the View use at least this value for its height. (There will be some scenarios where this will not be possible.) This value should INCLUDE any padding.
Returns the minimum width suggested by this Drawable. If a View uses this Drawable as a background, it is suggested that the View use at least this value for its width. (There will be some scenarios where this will not be possible.) This value should INCLUDE any padding.
Return the opacity/transparency of this Drawable. The returned value is
one of the abstract format constants in
PixelFormat:
UNKNOWN,
TRANSLUCENT,
TRANSPARENT, or
OPAQUE.
Generally a Drawable should be as conservative as possible with the
value it returns. For example, if it contains multiple child drawables
and only shows one of them at a time, if only one of the children is
TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be
returned. You can use the method resolveOpacity(int, int) to perform a
standard reduction of two opacities to the appropriate single output.
Note that the returned value does not take into account a
custom alpha or color filter that has been applied by the client through
the setAlpha(int) or setColorFilter(ColorFilter) methods.
Return in padding the insets suggested by this Drawable for placing content inside the drawable's bounds. Positive values move toward the center of the Drawable (set Rect.inset). Returns true if this drawable actually has a padding, else false. When false is returned, the padding is always set to 0.
Describes the current state, as a union of primitve states, such as
state_focused,
state_selected, etc.
Some drawables may modify their imagery based on the selected state.
Returns a Region representing the part of the Drawable that is completely transparent. This can be used to perform drawing operations, identifying which parts of the target will not change when rendering the Drawable. The default implementation returns null, indicating no transparent region; subclasses can optionally override this to return an actual Region if they want to supply this optimization information, but it is not required that they do so.
Inflate this Drawable from an XML resource.
Use the current Drawable.Callback implementation to have this Drawable
redrawn. Does nothing if there is no Callback attached to the
Drawable.
Tells if this Drawable will be automatically mirrored when its layout direction is RTL
right-to-left. See LayoutDirection.
Indicates whether this view will change its appearance based on state. Clients can use this to determine whether it is necessary to calculate their state and call setState.
If this Drawable does transition animations between states, ask that it immediately jump to the current state and skip any active animations.
Make this drawable mutable. This operation cannot be reversed. A mutable drawable is guaranteed to not share its state with any other drawable. This is especially useful when you need to modify properties of drawables loaded from resources. By default, all drawables instances loaded from the same resource share a common state; if you modify the state of one instance, all the other instances will receive the same modification. Calling this method on a mutable Drawable will have no effect.
Return the appropriate opacity value for two source opacities. If either is UNKNOWN, that is returned; else, if either is TRANSLUCENT, that is returned; else, if either is TRANSPARENT, that is returned; else, OPAQUE is returned.
This is to help in implementing getOpacity().
| op1 | One opacity value. |
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| op2 | Another opacity value. |
Use the current Drawable.Callback implementation to have this Drawable
scheduled. Does nothing if there is no Callback attached to the
Drawable.
| what | The action being scheduled. |
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| when | The time (in milliseconds) to run. |
Specify an alpha value for the drawable. 0 means fully transparent, and 255 means fully opaque.
Set whether this Drawable is automatically mirrored when its layout direction is RTL
(right-to left). See LayoutDirection.
| mirrored | Set to true if the Drawable should be mirrored, false if not. |
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Specify a bounding rectangle for the Drawable. This is where the drawable will draw when its draw() method is called.
Specify a bounding rectangle for the Drawable. This is where the drawable will draw when its draw() method is called.
Bind a Drawable.Callback object to this Drawable. Required for clients
that want to support animated drawables.
| cb | The client's Callback implementation. |
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Set a mask of the configuration parameters for which this drawable may change, requiring that it be re-created.
| configs | A mask of the changing configuration parameters, as
defined by Configuration. |
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Specify an optional colorFilter for the drawable. Pass null to remove any filters.
Specify a color and porterduff mode to be the colorfilter for this drawable.
Set to true to have the drawable dither its colors when drawn to a device with fewer than 8-bits per color component. This can improve the look on those devices, but can also slow down the drawing a little.
Set to true to have the drawable filter its bitmap when scaled or rotated (for drawables that use bitmaps). If the drawable does not use bitmaps, this call is ignored. This can improve the look when scaled or rotated, but also slows down the drawing.
Specify the level for the drawable. This allows a drawable to vary its imagery based on a continuous controller, for example to show progress or volume level.
If the new level you are supplying causes the appearance of the
Drawable to change, then it is responsible for calling
invalidateSelf() in order to have itself redrawn, and
true will be returned from this function.
| level | The new level, from 0 (minimum) to 10000 (maximum). |
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Specify a set of states for the drawable. These are use-case specific,
so see the relevant documentation. As an example, the background for
widgets like Button understand the following states:
[state_focused,
state_pressed].
If the new state you are supplying causes the appearance of the
Drawable to change, then it is responsible for calling
invalidateSelf() in order to have itself redrawn, and
true will be returned from this function.
Note: The Drawable holds a reference on to stateSet until a new state array is given to it, so you must not modify this array during that time.
| stateSet | The new set of states to be displayed. |
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Set whether this Drawable is visible. This generally does not impact the Drawable's behavior, but is a hint that can be used by some Drawables, for example, to decide whether run animations.
| visible | Set to true if visible, false if not. |
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| restart | You can supply true here to force the drawable to behave as if it has just become visible, even if it had last been set visible. Used for example to force animations to restart. |
Use the current Drawable.Callback implementation to have this Drawable
unscheduled. Does nothing if there is no Callback attached to the
Drawable.
| what | The runnable that you no longer want called. |
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Override this in your subclass to change appearance if you recognize the specified state.
Override this in your subclass to change appearance if you vary based on level.
Override this in your subclass to change appearance if you recognize the specified state.