In addition to simple drawing, Drawable provides a number of generic * mechanisms for its client to interact with what is being drawn: * *
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.
* By default, this returns the full drawable bounds. Custom drawables may
* override this method to perform more precise invalidation.
*
* @return The dirty bounds of this drawable
*/
public Rect getDirtyBounds() {
return getBounds();
}
/**
* Set a mask of the configuration parameters for which this drawable
* may change, requiring that it be re-created.
*
* @param configs A mask of the changing configuration parameters, as
* defined by {@link android.content.pm.ActivityInfo}.
*
* @see android.content.pm.ActivityInfo
*/
public void setChangingConfigurations(int configs) {
mChangingConfigurations = configs;
}
/**
* 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
* {@link #setChangingConfigurations(int)} or 0 by default. Subclasses
* may extend this to or in the changing configurations of any other
* drawables they hold.
*
* @return Returns a mask of the changing configuration parameters, as
* defined by {@link android.content.pm.ActivityInfo}.
*
* @see android.content.pm.ActivityInfo
*/
public int getChangingConfigurations() {
return mChangingConfigurations;
}
/**
* 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.
*/
public void setDither(boolean dither) {}
/**
* 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.
*/
public void setFilterBitmap(boolean filter) {}
/**
* Implement this interface if you want to create an animated drawable that
* extends {@link android.graphics.drawable.Drawable Drawable}.
* Upon retrieving a drawable, use
* {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)}
* to supply your implementation of the interface to the drawable; it uses
* this interface to schedule and execute animation changes.
*/
public static interface Callback {
/**
* Called when the drawable needs to be redrawn. A view at this point
* should invalidate itself (or at least the part of itself where the
* drawable appears).
*
* @param who The drawable that is requesting the update.
*/
public void invalidateDrawable(Drawable who);
/**
* A Drawable can call this to schedule the next frame of its
* animation. An implementation can generally simply call
* {@link android.os.Handler#postAtTime(Runnable, Object, long)} with
* the parameters (what, who, when) to perform the
* scheduling.
*
* @param who The drawable being scheduled.
* @param what The action to execute.
* @param when The time (in milliseconds) to run. The timebase is
* {@link android.os.SystemClock#uptimeMillis}
*/
public void scheduleDrawable(Drawable who, Runnable what, long when);
/**
* A Drawable can call this to unschedule an action previously
* scheduled with {@link #scheduleDrawable}. An implementation can
* generally simply call
* {@link android.os.Handler#removeCallbacks(Runnable, Object)} with
* the parameters (what, who) to unschedule the drawable.
*
* @param who The drawable being unscheduled.
* @param what The action being unscheduled.
*/
public void unscheduleDrawable(Drawable who, Runnable what);
}
/**
* Bind a {@link Callback} object to this Drawable. Required for clients
* that want to support animated drawables.
*
* @param cb The client's Callback implementation.
*
* @see #getCallback()
*/
public final void setCallback(Callback cb) {
mCallback = new WeakReference
* Setting a color filter via {@link #setColorFilter(ColorFilter)} overrides
* tint.
*
* @param tint Color to use for tinting this drawable
* @see #setTintMode(PorterDuff.Mode)
*/
public void setTint(int tint) {
setTintList(ColorStateList.valueOf(tint));
}
/**
* Specifies a tint for this drawable as a color state list.
*
* Setting a color filter via {@link #setColorFilter(ColorFilter)} overrides
* tint.
*
* @param tint Color state list to use for tinting this drawable, or null to
* clear the tint
* @see #setTintMode(PorterDuff.Mode)
*/
public void setTintList(ColorStateList tint) {}
/**
* Specifies a tint blending mode for this drawable.
*
* Setting a color filter via {@link #setColorFilter(ColorFilter)} overrides
* tint.
*
* @param tintMode Color state list to use for tinting this drawable, or null to
* clear the tint
* @param tintMode A Porter-Duff blending mode
*/
public void setTintMode(PorterDuff.Mode tintMode) {}
/**
* Returns the current color filter, or {@code null} if none set.
*
* @return the current color filter, or {@code null} if none set
*/
public ColorFilter getColorFilter() {
return null;
}
/**
* Removes the color filter for this drawable.
*/
public void clearColorFilter() {
setColorFilter(null);
}
/**
* Specifies the hotspot's location within the drawable.
*
* @param x The X coordinate of the center of the hotspot
* @param y The Y coordinate of the center of the hotspot
*/
public void setHotspot(float x, float y) {}
/**
* Sets the bounds to which the hotspot is constrained, if they should be
* different from the drawable bounds.
*
* @param left
* @param top
* @param right
* @param bottom
*/
public void setHotspotBounds(int left, int top, int right, int bottom) {}
/** @hide For internal use only. Individual results may vary. */
public void getHotspotBounds(Rect outRect) {
outRect.set(getBounds());
}
/**
* Whether this drawable requests projection.
*
* @hide magic!
*/
public boolean isProjected() {
return false;
}
/**
* 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.
*
* @return True if this drawable changes its appearance based on state,
* false otherwise.
* @see #setState(int[])
*/
public boolean isStateful() {
return false;
}
/**
* 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:
* [{@link android.R.attr#state_focused},
* {@link android.R.attr#state_pressed}].
*
* If the new state you are supplying causes the appearance of the
* Drawable to change, then it is responsible for calling
* {@link #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. If the new level you are supplying causes the appearance of the
* Drawable to change, then it is responsible for calling
* {@link #invalidateSelf} in order to have itself redrawn, and
* true will be returned from this function.
*
* @param level The new level, from 0 (minimum) to 10000 (maximum).
*
* @return Returns true if this change in level has caused the appearance
* of the Drawable to change (hence requiring an invalidate), otherwise
* returns false.
*/
public final boolean setLevel(int level) {
if (mLevel != level) {
mLevel = level;
return onLevelChange(level);
}
return false;
}
/**
* Retrieve the current level.
*
* @return int Current level, from 0 (minimum) to 10000 (maximum).
*/
public final int getLevel() {
return mLevel;
}
/**
* 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.
*
* @param visible Set to true if visible, false if not.
* @param 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.
*
* @return boolean Returns true if the new visibility is different than
* its previous state.
*/
public boolean setVisible(boolean visible, boolean restart) {
boolean changed = mVisible != visible;
if (changed) {
mVisible = visible;
invalidateSelf();
}
return changed;
}
public final boolean isVisible() {
return mVisible;
}
/**
* Set whether this Drawable is automatically mirrored when its layout direction is RTL
* (right-to left). See {@link android.util.LayoutDirection}.
*
* @param mirrored Set to true if the Drawable should be mirrored, false if not.
*/
public void setAutoMirrored(boolean mirrored) {
}
/**
* Tells if this Drawable will be automatically mirrored when its layout direction is RTL
* right-to-left. See {@link android.util.LayoutDirection}.
*
* @return boolean Returns true if this Drawable will be automatically mirrored.
*/
public boolean isAutoMirrored() {
return false;
}
/**
* Applies the specified theme to this Drawable and its children.
*/
public void applyTheme(@SuppressWarnings("unused") Theme t) {
}
public boolean canApplyTheme() {
return false;
}
/**
* Return the opacity/transparency of this Drawable. The returned value is
* one of the abstract format constants in
* {@link android.graphics.PixelFormat}:
* {@link android.graphics.PixelFormat#UNKNOWN},
* {@link android.graphics.PixelFormat#TRANSLUCENT},
* {@link android.graphics.PixelFormat#TRANSPARENT}, or
* {@link android.graphics.PixelFormat#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 {@link #resolveOpacity} 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 {@link #setAlpha} or {@link #setColorFilter} methods.
*
* @return int The opacity class of the Drawable.
*
* @see android.graphics.PixelFormat
*/
public abstract int getOpacity();
/**
* 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 {@link #getOpacity}.
*
* @param op1 One opacity value.
* @param op2 Another opacity value.
*
* @return int The combined opacity value.
*
* @see #getOpacity
*/
public static int resolveOpacity(int op1, int op2) {
if (op1 == op2) {
return op1;
}
if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) {
return PixelFormat.UNKNOWN;
}
if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) {
return PixelFormat.TRANSLUCENT;
}
if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) {
return PixelFormat.TRANSPARENT;
}
return PixelFormat.OPAQUE;
}
/**
* 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.
*
* @return Returns null if the Drawables has no transparent region to
* report, else a Region holding the parts of the Drawable's bounds that
* are transparent.
*/
public Region getTransparentRegion() {
return null;
}
/**
* Override this in your subclass to change appearance if you recognize the
* specified state.
*
* @return 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.
*/
protected boolean onStateChange(int[] state) { return false; }
/** Override this in your subclass to change appearance if you vary based
* on level.
* @return Returns true if the level 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 level.
*/
protected boolean onLevelChange(int level) { return false; }
/**
* Override this in your subclass to change appearance if you vary based on
* the bounds.
*/
protected void onBoundsChange(Rect bounds) {}
/**
* Return the intrinsic width of the underlying drawable object. Returns
* -1 if it has no intrinsic width, such as with a solid color.
*/
public int getIntrinsicWidth() {
return -1;
}
/**
* Return the intrinsic height of the underlying drawable object. Returns
* -1 if it has no intrinsic height, such as with a solid color.
*/
public int getIntrinsicHeight() {
return -1;
}
/**
* 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 minimum width suggested by this Drawable. If this Drawable
* doesn't have a suggested minimum width, 0 is returned.
*/
public int getMinimumWidth() {
final int intrinsicWidth = getIntrinsicWidth();
return intrinsicWidth > 0 ? intrinsicWidth : 0;
}
/**
* 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.
*
* @return The minimum height suggested by this Drawable. If this Drawable
* doesn't have a suggested minimum height, 0 is returned.
*/
public int getMinimumHeight() {
final int intrinsicHeight = getIntrinsicHeight();
return intrinsicHeight > 0 ? intrinsicHeight : 0;
}
/**
* 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).
*
* @return true if this drawable actually has a padding, else false. When false is returned,
* the padding is always set to 0.
*/
public boolean getPadding(@NonNull Rect padding) {
padding.set(0, 0, 0, 0);
return false;
}
/**
* Return in insets the layout insets suggested by this Drawable for use with alignment
* operations during layout.
*
* @hide
*/
public Insets getOpticalInsets() {
return Insets.NONE;
}
/**
* Called to get the drawable to populate the Outline that defines its drawing area.
*
* This method is called by the default {@link android.view.ViewOutlineProvider} to define
* the outline of the View.
*
* The default behavior defines the outline to be the bounding rectangle of 0 alpha.
* Subclasses that wish to convey a different shape or alpha value must override this method.
*
* @see android.view.View#setOutlineProvider(android.view.ViewOutlineProvider)
*/
public void getOutline(@NonNull Outline outline) {
outline.setRect(getBounds());
outline.setAlpha(0);
}
/**
* 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 This drawable.
* @see ConstantState
* @see #getConstantState()
*/
public Drawable mutate() {
return this;
}
/**
* Clears the mutated state, allowing this drawable to be cached and
* mutated again.
*
* This is hidden because only framework drawables can be cached, so
* custom drawables don't need to support constant state, mutate(), or
* clearMutated().
*
* @hide
*/
public void clearMutated() {
// Default implementation is no-op.
}
/**
* Create a drawable from an inputstream
*/
public static Drawable createFromStream(InputStream is, String srcName) {
Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable");
try {
return createFromResourceStream(null, null, is, srcName);
} finally {
Trace.traceEnd(Trace.TRACE_TAG_RESOURCES);
}
}
/**
* Create a drawable from an inputstream, using the given resources and
* value to determine density information.
*/
public static Drawable createFromResourceStream(Resources res, TypedValue value,
InputStream is, String srcName) {
Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, srcName != null ? srcName : "Unknown drawable");
try {
return createFromResourceStream(res, value, is, srcName, null);
} finally {
Trace.traceEnd(Trace.TRACE_TAG_RESOURCES);
}
}
/**
* Create a drawable from an inputstream, using the given resources and
* value to determine density information.
*/
public static Drawable createFromResourceStream(Resources res, TypedValue value,
InputStream is, String srcName, BitmapFactory.Options opts) {
if (is == null) {
return null;
}
/* ugh. The decodeStream contract is that we have already allocated
the pad rect, but if the bitmap does not had a ninepatch chunk,
then the pad will be ignored. If we could change this to lazily
alloc/assign the rect, we could avoid the GC churn of making new
Rects only to drop them on the floor.
*/
Rect pad = new Rect();
// Special stuff for compatibility mode: if the target density is not
// the same as the display density, but the resource -is- the same as
// the display density, then don't scale it down to the target density.
// This allows us to load the system's density-correct resources into
// an application in compatibility mode, without scaling those down
// to the compatibility density only to have them scaled back up when
// drawn to the screen.
if (opts == null) opts = new BitmapFactory.Options();
opts.inScreenDensity = res != null
? res.getDisplayMetrics().noncompatDensityDpi : DisplayMetrics.DENSITY_DEVICE;
Bitmap bm = BitmapFactory.decodeResourceStream(res, value, is, pad, opts);
if (bm != null) {
byte[] np = bm.getNinePatchChunk();
if (np == null || !NinePatch.isNinePatchChunk(np)) {
np = null;
pad = null;
}
final Rect opticalInsets = new Rect();
bm.getOpticalInsets(opticalInsets);
return drawableFromBitmap(res, bm, np, pad, opticalInsets, srcName);
}
return null;
}
/**
* Create a drawable from an XML document. For more information on how to
* create resources in XML, see
* Drawable Resources.
*/
public static Drawable createFromXml(Resources r, XmlPullParser parser)
throws XmlPullParserException, IOException {
return createFromXml(r, parser, null);
}
/**
* Create a drawable from an XML document using an optional {@link Theme}.
* For more information on how to create resources in XML, see
* Drawable Resources.
*/
public static Drawable createFromXml(Resources r, XmlPullParser parser, Theme theme)
throws XmlPullParserException, IOException {
AttributeSet attrs = Xml.asAttributeSet(parser);
int type;
while ((type=parser.next()) != XmlPullParser.START_TAG &&
type != XmlPullParser.END_DOCUMENT) {
// Empty loop
}
if (type != XmlPullParser.START_TAG) {
throw new XmlPullParserException("No start tag found");
}
Drawable drawable = createFromXmlInner(r, parser, attrs, theme);
if (drawable == null) {
throw new RuntimeException("Unknown initial tag: " + parser.getName());
}
return drawable;
}
/**
* 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.
*/
public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs)
throws XmlPullParserException, IOException {
return createFromXmlInner(r, parser, attrs, null);
}
/**
* Create a drawable from inside an XML document using an optional
* {@link Theme}. Called on a parser positioned at a tag in an XML
* document, tries to create a Drawable from that tag. Returns {@code null}
* if the tag is not a valid drawable.
*/
public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs,
Theme theme) throws XmlPullParserException, IOException {
final Drawable drawable;
final String name = parser.getName();
switch (name) {
case "selector":
drawable = new StateListDrawable();
break;
case "animated-selector":
drawable = new AnimatedStateListDrawable();
break;
case "level-list":
drawable = new LevelListDrawable();
break;
case "layer-list":
drawable = new LayerDrawable();
break;
case "transition":
drawable = new TransitionDrawable();
break;
case "ripple":
drawable = new RippleDrawable();
break;
case "color":
drawable = new ColorDrawable();
break;
case "shape":
drawable = new GradientDrawable();
break;
case "vector":
drawable = new VectorDrawable();
break;
case "animated-vector":
drawable = new AnimatedVectorDrawable();
break;
case "scale":
drawable = new ScaleDrawable();
break;
case "clip":
drawable = new ClipDrawable();
break;
case "rotate":
drawable = new RotateDrawable();
break;
case "animated-rotate":
drawable = new AnimatedRotateDrawable();
break;
case "animation-list":
drawable = new AnimationDrawable();
break;
case "inset":
drawable = new InsetDrawable();
break;
case "bitmap":
drawable = new BitmapDrawable(r);
if (r != null) {
((BitmapDrawable) drawable).setTargetDensity(r.getDisplayMetrics());
}
break;
case "nine-patch":
drawable = new NinePatchDrawable();
if (r != null) {
((NinePatchDrawable) drawable).setTargetDensity(r.getDisplayMetrics());
}
break;
default:
throw new XmlPullParserException(parser.getPositionDescription() +
": invalid drawable tag " + name);
}
drawable.inflate(r, parser, attrs, theme);
return drawable;
}
/**
* Create a drawable from file path name.
*/
public static Drawable createFromPath(String pathName) {
if (pathName == null) {
return null;
}
Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, pathName);
try {
Bitmap bm = BitmapFactory.decodeFile(pathName);
if (bm != null) {
return drawableFromBitmap(null, bm, null, null, null, pathName);
}
} finally {
Trace.traceEnd(Trace.TRACE_TAG_RESOURCES);
}
return null;
}
/**
* Inflate this Drawable from an XML resource. Does not apply a theme.
*
* @see #inflate(Resources, XmlPullParser, AttributeSet, Theme)
*/
public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs)
throws XmlPullParserException, IOException {
inflate(r, parser, attrs, null);
}
/**
* Inflate this Drawable from an XML resource optionally styled by a theme.
*
* @param r Resources used to resolve attribute values
* @param parser XML parser from which to inflate this Drawable
* @param attrs Base set of attribute values
* @param theme Theme to apply, may be null
* @throws XmlPullParserException
* @throws IOException
*/
public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs, Theme theme)
throws XmlPullParserException, IOException {
final TypedArray a;
if (theme != null) {
a = theme.obtainStyledAttributes(
attrs, com.android.internal.R.styleable.Drawable, 0, 0);
} else {
a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable);
}
inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible);
a.recycle();
}
/**
* Inflate a Drawable from an XML resource.
*
* @throws XmlPullParserException
* @throws IOException
*/
void inflateWithAttributes(Resources r, XmlPullParser parser, TypedArray attrs, int visibleAttr)
throws XmlPullParserException, IOException {
mVisible = attrs.getBoolean(visibleAttr, mVisible);
}
/**
* This abstract class is used by {@link Drawable}s to store shared constant state and data
* between Drawables. {@link BitmapDrawable}s created from the same resource will for instance
* share a unique bitmap stored in their ConstantState.
*
*
* {@link #newDrawable(Resources)} can be used as a factory to create new Drawable instances
* from this ConstantState.
*