StateListDrawable


public class StateListDrawable
extends DrawableContainer

java.lang.Object
   ↳ android.graphics.drawable.Drawable
     ↳ android.graphics.drawable.DrawableContainer
       ↳ android.graphics.drawable.StateListDrawable


Lets you assign a number of graphic images to a single Drawable and swap out the visible item by a string ID value.

It can be defined in an XML file with the <selector> element. Each state Drawable is defined in a nested <item> element. For more information, see the guide to Drawable Resources.

Summary

XML attributes

android:constantSize If true, the drawable's reported internal size will remain constant as the state changes; the size is the maximum of all of the states. 
android:state_activated State value for StateListDrawable, set when a view or its parent has been "activated" meaning the user has currently marked it as being of interest. 
android:state_active State value for StateListDrawable, set when a view or drawable is considered "active" by its host. 
android:state_checkable State identifier indicating that the object may display a check mark. 
android:state_checked State identifier indicating that the object is currently checked. 
android:state_enabled State value for StateListDrawable, set when a view is enabled. 
android:state_first State value for StateListDrawable, set when a view or drawable is in the first position in an ordered set. 
android:state_focused State value for StateListDrawable, set when a view has input focus. 
android:state_last State value for StateListDrawable, set when a view or drawable is in the last position in an ordered set. 
android:state_middle State value for StateListDrawable, set when a view or drawable is in the middle position in an ordered set. 
android:state_pressed State value for StateListDrawable, set when the user is pressing down in a view. 
android:state_selected State value for StateListDrawable, set when a view (or one of its parents) is currently selected. 
android:state_single State value for StateListDrawable, set when a view or drawable is considered "single" by its host. 
android:state_window_focused State value for StateListDrawable, set when a view's window has input focus. 
android:variablePadding If true, allows the drawable's padding to change based on the current state that is selected. 
android:visible Indicates whether the drawable should be initially visible. 

Public constructors

StateListDrawable()

Public methods

void addState(int[] stateSet, Drawable drawable)

Add a new image/string ID to the set of images.

void applyTheme(Resources.Theme theme)

Applies the specified theme to this Drawable and its children.

int findStateDrawableIndex(int[] stateSet)

Gets the index of the drawable with the provided state set.

int getStateCount()

Gets the number of states contained in this drawable.

Drawable getStateDrawable(int index)

Gets the drawable at an index.

int[] getStateSet(int index)

Gets the state set at an index.

boolean hasFocusStateSpecified()

Indicates whether this drawable has at least one state spec explicitly specifying R.attr.state_focused.

void inflate(Resources r, XmlPullParser parser, AttributeSet attrs, Resources.Theme theme)

Inflate this Drawable from an XML resource optionally styled by a theme.

boolean isStateful()

Indicates whether this drawable will change its appearance based on state.

Drawable mutate()

Make this drawable mutable.

Protected methods

boolean onStateChange(int[] stateSet)

Override this in your subclass to change appearance if you recognize the specified state.

void setConstantState(DrawableContainer.DrawableContainerState state)

Inherited methods

XML attributes

android:constantSize

If true, the drawable's reported internal size will remain constant as the state changes; the size is the maximum of all of the states. If false, the size will vary based on the current state.

May be a boolean value, such as "true" or "false".

android:state_activated

State value for StateListDrawable, set when a view or its parent has been "activated" meaning the user has currently marked it as being of interest. This is an alternative representation of state_checked for when the state should be propagated down the view hierarchy.

May be a boolean value, such as "true" or "false".

android:state_active

State value for StateListDrawable, set when a view or drawable is considered "active" by its host. Actual usage may vary between views. Consult the host view documentation for details.

May be a boolean value, such as "true" or "false".

android:state_checkable

State identifier indicating that the object may display a check mark. See R.attr.state_checked for the identifier that indicates whether it is actually checked.

May be a boolean value, such as "true" or "false".

android:state_checked

State identifier indicating that the object is currently checked. See R.attr.state_checkable for an additional identifier that can indicate if any object may ever display a check, regardless of whether state_checked is currently set.

May be a boolean value, such as "true" or "false".

android:state_enabled

State value for StateListDrawable, set when a view is enabled.

May be a boolean value, such as "true" or "false".

android:state_first

State value for StateListDrawable, set when a view or drawable is in the first position in an ordered set. Actual usage may vary between views. Consult the host view documentation for details.

May be a boolean value, such as "true" or "false".

android:state_focused

State value for StateListDrawable, set when a view has input focus.

May be a boolean value, such as "true" or "false".

android:state_last

State value for StateListDrawable, set when a view or drawable is in the last position in an ordered set. Actual usage may vary between views. Consult the host view documentation for details.

May be a boolean value, such as "true" or "false".

android:state_middle

State value for StateListDrawable, set when a view or drawable is in the middle position in an ordered set. Actual usage may vary between views. Consult the host view documentation for details.

May be a boolean value, such as "true" or "false".

android:state_pressed

State value for StateListDrawable, set when the user is pressing down in a view.

May be a boolean value, such as "true" or "false".

android:state_selected

State value for StateListDrawable, set when a view (or one of its parents) is currently selected.

May be a boolean value, such as "true" or "false".

android:state_single

State value for StateListDrawable, set when a view or drawable is considered "single" by its host. Actual usage may vary between views. Consult the host view documentation for details.

May be a boolean value, such as "true" or "false".

android:state_window_focused

State value for StateListDrawable, set when a view's window has input focus.

May be a boolean value, such as "true" or "false".

android:variablePadding

If true, allows the drawable's padding to change based on the current state that is selected. If false, the padding will stay the same (based on the maximum padding of all the states). Enabling this feature requires that the owner of the drawable deal with performing layout when the state changes, which is often not supported.

May be a boolean value, such as "true" or "false".

android:visible

Indicates whether the drawable should be initially visible.

May be a boolean value, such as "true" or "false".

Public constructors

StateListDrawable

Added in API level 1
public StateListDrawable ()

Public methods

addState

Added in API level 1
public void addState (int[] stateSet, 
                Drawable drawable)

Add a new image/string ID to the set of images.

Parameters
stateSet int: An array of resource Ids to associate with the image. Switch to this image by calling setState().

drawable Drawable: The image to show. Note this must be a unique Drawable that is not shared between any other View or Drawable otherwise the results are undefined and can lead to unexpected rendering behavior

applyTheme

Added in API level 21
public void applyTheme (Resources.Theme theme)

Applies the specified theme to this Drawable and its children.

Parameters
theme Resources.Theme: the theme to apply This value cannot be null.

findStateDrawableIndex

Added in API level 29
public int findStateDrawableIndex (int[] stateSet)

Gets the index of the drawable with the provided state set.

Parameters
stateSet int: the state set to look up This value cannot be null.

Returns
int the index of the provided state set, or -1 if not found

getStateCount

Added in API level 29
public int getStateCount ()

Gets the number of states contained in this drawable.

Returns
int The number of states contained in this drawable.

getStateDrawable

Added in API level 29
public Drawable getStateDrawable (int index)

Gets the drawable at an index.

Parameters
index int: The index of the drawable.

Returns
Drawable The drawable at the index. This value may be null.

getStateSet

Added in API level 29
public int[] getStateSet (int index)

Gets the state set at an index.

Parameters
index int: The index of the state set.

Returns
int[] The state set at the index. This value cannot be null.

hasFocusStateSpecified

Added in API level 31
public boolean hasFocusStateSpecified ()

Indicates whether this drawable has at least one state spec explicitly specifying R.attr.state_focused.

Note: A View uses a Drawable instance as its background and it changes its appearance based on a state. On keyboard devices, it should specify its R.attr.state_focused to make sure the user knows which view is holding the focus.

Returns
boolean true if R.attr.state_focused is specified for this drawable.

inflate

Added in API level 21
public void inflate (Resources r, 
                XmlPullParser parser, 
                AttributeSet attrs, 
                Resources.Theme theme)

Inflate this Drawable from an XML resource optionally styled by a theme. This can't be called more than once for each Drawable. Note that framework may have called this once to create the Drawable instance from XML resource.

Parameters
r Resources: Resources used to resolve attribute values This value cannot be null.

parser XmlPullParser: XML parser from which to inflate this Drawable This value cannot be null.

attrs AttributeSet: Base set of attribute values This value cannot be null.

theme Resources.Theme: Theme to apply, may be null

Throws
IOException
XmlPullParserException

isStateful

Added in API level 1
public boolean isStateful ()

Indicates whether this drawable will change its appearance based on state. Clients can use this to determine whether it is necessary to calculate their state and call setState.

Returns
boolean True if this drawable changes its appearance based on state, false otherwise.

mutate

Added in API level 3
public Drawable mutate ()

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.

Returns
Drawable This drawable. This value cannot be null.

Protected methods

onStateChange

Added in API level 1
protected boolean onStateChange (int[] stateSet)

Override this in your subclass to change appearance if you recognize the specified state.

Parameters
stateSet int: This value cannot be null.

Returns
boolean Returns true if the state change has caused the appearance of the Drawable to change (that is, it needs to be drawn), else false if it looks the same and there is no need to redraw it since its last state.

setConstantState

Added in API level 1
protected void setConstantState (DrawableContainer.DrawableContainerState state)

Parameters
state DrawableContainer.DrawableContainerState: This value cannot be null.