Java tutorial
/* * Copyright (C) 2006 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package android.graphics.drawable; import com.android.internal.R; import org.xmlpull.v1.XmlPullParser; import org.xmlpull.v1.XmlPullParserException; import android.annotation.AttrRes; import android.annotation.ColorInt; import android.annotation.IntRange; import android.annotation.NonNull; import android.annotation.Nullable; import android.annotation.TestApi; import android.annotation.UnsupportedAppUsage; import android.content.pm.ActivityInfo.Config; import android.content.res.ColorStateList; import android.content.res.Resources; import android.content.res.Resources.Theme; import android.content.res.TypedArray; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.ColorFilter; import android.graphics.ImageDecoder; import android.graphics.Insets; import android.graphics.NinePatch; import android.graphics.Outline; import android.graphics.PixelFormat; import android.graphics.PorterDuff; import android.graphics.PorterDuff.Mode; import android.graphics.PorterDuffColorFilter; import android.graphics.Rect; import android.graphics.Region; import android.graphics.Xfermode; import android.os.Trace; import android.util.AttributeSet; import android.util.DisplayMetrics; import android.util.Log; import android.util.StateSet; import android.util.TypedValue; import android.util.Xml; import android.view.View; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.lang.ref.WeakReference; import java.util.Arrays; /** * 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 {@link android.view.View}, a Drawable does not have any facility to * receive events or otherwise interact with the user. * * <p>In addition to simple drawing, Drawable provides a number of generic * mechanisms for its client to interact with what is being drawn: * * <ul> * <li> The {@link #setBounds} method <var>must</var> 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 {@link #getIntrinsicHeight} and {@link #getIntrinsicWidth} methods. * * <li> The {@link #getPadding} 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. * * <li> The {@link #setState} 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. * * <li> The {@link #setLevel} 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. * * <li> A Drawable can perform animations by calling back to its client * through the {@link Callback} interface. All clients should support this * interface (via {@link #setCallback}) so that animations will work. A * simple way to do this is through the system facilities such as * {@link android.view.View#setBackground(Drawable)} and * {@link android.widget.ImageView}. * </ul> * * Though usually not visible to the application, Drawables may take a variety * of forms: * * <ul> * <li> <b>Bitmap</b>: the simplest Drawable, a PNG or JPEG image. * <li> <b>Nine Patch</b>: an extension to the PNG format allows it to * specify information about how to stretch it and place things inside of * it. * <li><b>Vector</b>: a drawable defined in an XML file as a set of points, * lines, and curves along with its associated color information. This type * of drawable can be scaled without loss of display quality. * <li> <b>Shape</b>: contains simple drawing commands instead of a raw * bitmap, allowing it to resize better in some cases. * <li> <b>Layers</b>: a compound drawable, which draws multiple underlying * drawables on top of each other. * <li> <b>States</b>: a compound drawable that selects one of a set of * drawables based on its state. * <li> <b>Levels</b>: a compound drawable that selects one of a set of * drawables based on its level. * <li> <b>Scale</b>: a compound drawable with a single child drawable, * whose overall size is modified based on the current level. * </ul> * * <a name="Custom"></a> * <h3>Custom drawables</h3> * * <p> * All versions of Android allow the Drawable class to be extended and used at * run time in place of framework-provided drawable classes. Starting in * {@link android.os.Build.VERSION_CODES#N API 24}, custom drawables classes * may also be used in XML. * <p> * <strong>Note:</strong> Custom drawable classes are only accessible from * within your application package. Other applications will not be able to load * them. * <p> * At a minimum, custom drawable classes must implement the abstract methods on * Drawable and should override the {@link Drawable#draw(Canvas)} method to * draw content. * <p> * Custom drawables classes may be used in XML in multiple ways: * <ul> * <li> * Using the fully-qualified class name as the XML element name. For * this method, the custom drawable class must be a public top-level * class. * <pre> * <com.myapp.MyCustomDrawable xmlns:android="http://schemas.android.com/apk/res/android" * android:color="#ffff0000" /> * </pre> * </li> * <li> * Using <em>drawable</em> as the XML element name and specifying the * fully-qualified class name from the <em>class</em> attribute. This * method may be used for both public top-level classes and public * static inner classes. * <pre> * <drawable xmlns:android="http://schemas.android.com/apk/res/android" * class="com.myapp.MyTopLevelClass$InnerCustomDrawable" * android:color="#ffff0000" /> * </pre> * </li> * </ul> * * <div class="special reference"> * <h3>Developer Guides</h3> * <p>For more information about how to use drawables, read the * <a href="{@docRoot}guide/topics/graphics/2d-graphics.html">Canvas and Drawables</a> developer * guide. For information and examples of creating drawable resources (XML or bitmap files that * can be loaded in code), read the * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a> * document.</p></div> */ public abstract class Drawable { private static final Rect ZERO_BOUNDS_RECT = new Rect(); static final PorterDuff.Mode DEFAULT_TINT_MODE = PorterDuff.Mode.SRC_IN; private int[] mStateSet = StateSet.WILD_CARD; private int mLevel = 0; private @Config int mChangingConfigurations = 0; private Rect mBounds = ZERO_BOUNDS_RECT; // lazily becomes a new Rect() @UnsupportedAppUsage private WeakReference<Callback> mCallback = null; private boolean mVisible = true; private int mLayoutDirection; /** * The source density to use when looking up resources using * {@link Resources#getDrawableForDensity(int, int, Theme)}. A value of 0 means there is no * override and the system density will be used. * * NOTE(adamlesinski): This is transient state used to get around the public API that does not * account for source density overrides. Custom drawables implemented by developers do not need * to be aware of the source density override, as it is only used by Launcher to load higher * resolution icons from external Resources packages, which do not execute custom code. * This is all to support the {@link Resources#getDrawableForDensity(int, int, Theme)} API. * * @hide */ @UnsupportedAppUsage protected int mSrcDensityOverride = 0; /** * Draw in its bounds (set via setBounds) respecting optional effects such * as alpha (set via setAlpha) and color filter (set via setColorFilter). * * @param canvas The canvas to draw into */ public abstract void draw(@NonNull Canvas canvas); /** * Specify a bounding rectangle for the Drawable. This is where the drawable * will draw when its draw() method is called. */ public void setBounds(int left, int top, int right, int bottom) { Rect oldBounds = mBounds; if (oldBounds == ZERO_BOUNDS_RECT) { oldBounds = mBounds = new Rect(); } if (oldBounds.left != left || oldBounds.top != top || oldBounds.right != right || oldBounds.bottom != bottom) { if (!oldBounds.isEmpty()) { // first invalidate the previous bounds invalidateSelf(); } mBounds.set(left, top, right, bottom); onBoundsChange(mBounds); } } /** * Specify a bounding rectangle for the Drawable. This is where the drawable * will draw when its draw() method is called. */ public void setBounds(@NonNull Rect bounds) { setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom); } /** * 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. * * @param bounds Rect to receive the drawable's bounds (allocated by the * caller). */ public final void copyBounds(@NonNull Rect bounds) { bounds.set(mBounds); } /** * 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 */ @NonNull public final Rect copyBounds() { return new Rect(mBounds); } /** * 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 bounds of the drawable (which may change later, so caller * beware). DO NOT ALTER the returned object as it may change the * stored bounds of this drawable. * * @see #copyBounds() * @see #copyBounds(android.graphics.Rect) */ @NonNull public final Rect getBounds() { if (mBounds == ZERO_BOUNDS_RECT) { mBounds = new Rect(); } return mBounds; } /** * Return the drawable's dirty bounds Rect. Note: for efficiency, the * returned object may be the same object stored in the drawable (though * this is not guaranteed). * <p> * 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 */ @NonNull 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(@Config 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 @Config 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. * * @see android.graphics.Paint#setDither(boolean); * @deprecated This property is ignored. */ @Deprecated public void setDither(boolean dither) { } /** * Set to true to have the drawable filter its bitmaps with bilinear * sampling when they are scaled or rotated. * * <p>This can improve appearance when bitmaps are rotated. If the drawable * does not use bitmaps, this call is ignored.</p> * * @see #isFilterBitmap() * @see android.graphics.Paint#setFilterBitmap(boolean); */ public void setFilterBitmap(boolean filter) { } /** * @return whether this drawable filters its bitmaps * @see #setFilterBitmap(boolean) */ public boolean isFilterBitmap() { return false; } /** * 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 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. */ void invalidateDrawable(@NonNull 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 <var>(what, who, when)</var> 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} */ void scheduleDrawable(@NonNull Drawable who, @NonNull 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 <var>(what, who)</var> to unschedule the drawable. * * @param who The drawable being unscheduled. * @param what The action being unscheduled. */ void unscheduleDrawable(@NonNull Drawable who, @NonNull 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(@Nullable Callback cb) { mCallback = cb != null ? new WeakReference<>(cb) : null; } /** * Return the current {@link Callback} implementation attached to this * Drawable. * * @return A {@link Callback} instance or null if no callback was set. * * @see #setCallback(android.graphics.drawable.Drawable.Callback) */ @Nullable public Callback getCallback() { return mCallback != null ? mCallback.get() : null; } /** * Use the current {@link Callback} implementation to have this Drawable * redrawn. Does nothing if there is no Callback attached to the * Drawable. * * @see Callback#invalidateDrawable * @see #getCallback() * @see #setCallback(android.graphics.drawable.Drawable.Callback) */ public void invalidateSelf() { final Callback callback = getCallback(); if (callback != null) { callback.invalidateDrawable(this); } } /** * Use the current {@link Callback} implementation to have this Drawable * scheduled. Does nothing if there is no Callback attached to the * Drawable. * * @param what The action being scheduled. * @param when The time (in milliseconds) to run. * * @see Callback#scheduleDrawable */ public void scheduleSelf(@NonNull Runnable what, long when) { final Callback callback = getCallback(); if (callback != null) { callback.scheduleDrawable(this, what, when); } } /** * Use the current {@link Callback} implementation to have this Drawable * unscheduled. Does nothing if there is no Callback attached to the * Drawable. * * @param what The runnable that you no longer want called. * * @see Callback#unscheduleDrawable */ public void unscheduleSelf(@NonNull Runnable what) { final Callback callback = getCallback(); if (callback != null) { callback.unscheduleDrawable(this, what); } } /** * Returns the resolved layout direction for this Drawable. * * @return One of {@link android.view.View#LAYOUT_DIRECTION_LTR}, * {@link android.view.View#LAYOUT_DIRECTION_RTL} * @see #setLayoutDirection(int) */ public @View.ResolvedLayoutDir int getLayoutDirection() { return mLayoutDirection; } /** * Set the layout direction for this drawable. Should be a resolved * layout direction, as the Drawable has no capacity to do the resolution on * its own. * * @param layoutDirection the resolved layout direction for the drawable, * either {@link android.view.View#LAYOUT_DIRECTION_LTR} * or {@link android.view.View#LAYOUT_DIRECTION_RTL} * @return {@code true} if the layout direction change has caused the * appearance of the drawable to change such that it needs to be * re-drawn, {@code false} otherwise * @see #getLayoutDirection() */ public final boolean setLayoutDirection(@View.ResolvedLayoutDir int layoutDirection) { if (mLayoutDirection != layoutDirection) { mLayoutDirection = layoutDirection; return onLayoutDirectionChanged(layoutDirection); } return false; } /** * Called when the drawable's resolved layout direction changes. * * @param layoutDirection the new resolved layout direction * @return {@code true} if the layout direction change has caused the * appearance of the drawable to change such that it needs to be * re-drawn, {@code false} otherwise * @see #setLayoutDirection(int) */ public boolean onLayoutDirectionChanged(@View.ResolvedLayoutDir int layoutDirection) { return false; } /** * Specify an alpha value for the drawable. 0 means fully transparent, and * 255 means fully opaque. */ public abstract void setAlpha(@IntRange(from = 0, to = 255) int alpha); /** * 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. */ @IntRange(from = 0, to = 255) public int getAlpha() { return 0xFF; } /** * @hide * * Internal-only method for setting xfermode on certain supported drawables. * * Should not be made public since the layers and drawing area with which * Drawables draw is private implementation detail, and not something apps * should rely upon. */ public void setXfermode(@Nullable Xfermode mode) { // Base implementation drops it on the floor for compatibility. Whee! } /** * Specify an optional color filter for the drawable. * <p> * If a Drawable has a ColorFilter, each output pixel of the Drawable's * drawing contents will be modified by the color filter before it is * blended onto the render target of a Canvas. * </p> * <p> * Pass {@code null} to remove any existing color filter. * </p> * <p class="note"><strong>Note:</strong> Setting a non-{@code null} color * filter disables {@link #setTintList(ColorStateList) tint}. * </p> * * @param colorFilter The color filter to apply, or {@code null} to remove the * existing color filter */ public abstract void setColorFilter(@Nullable ColorFilter colorFilter); /** * Specify a color and Porter-Duff mode to be the color filter for this * drawable. * <p> * Convenience for {@link #setColorFilter(ColorFilter)} which constructs a * {@link PorterDuffColorFilter}. * </p> * <p class="note"><strong>Note:</strong> Setting a color filter disables * {@link #setTintList(ColorStateList) tint}. * </p> */ public void setColorFilter(@ColorInt int color, @NonNull PorterDuff.Mode mode) { if (getColorFilter() instanceof PorterDuffColorFilter) { PorterDuffColorFilter existing = (PorterDuffColorFilter) getColorFilter(); if (existing.getColor() == color && existing.getMode() == mode) { return; } } setColorFilter(new PorterDuffColorFilter(color, mode)); } /** * Specifies tint color for this drawable. * <p> * A Drawable's drawing content will be blended together with its tint * before it is drawn to the screen. This functions similarly to * {@link #setColorFilter(int, PorterDuff.Mode)}. * </p> * <p> * To clear the tint, pass {@code null} to * {@link #setTintList(ColorStateList)}. * </p> * <p class="note"><strong>Note:</strong> Setting a color filter via * {@link #setColorFilter(ColorFilter)} or * {@link #setColorFilter(int, PorterDuff.Mode)} overrides tint. * </p> * * @param tintColor Color to use for tinting this drawable * @see #setTintList(ColorStateList) * @see #setTintMode(PorterDuff.Mode) */ public void setTint(@ColorInt int tintColor) { setTintList(ColorStateList.valueOf(tintColor)); } /** * Specifies tint color for this drawable as a color state list. * <p> * A Drawable's drawing content will be blended together with its tint * before it is drawn to the screen. This functions similarly to * {@link #setColorFilter(int, PorterDuff.Mode)}. * </p> * <p class="note"><strong>Note:</strong> Setting a color filter via * {@link #setColorFilter(ColorFilter)} or * {@link #setColorFilter(int, PorterDuff.Mode)} overrides tint. * </p> * * @param tint Color state list to use for tinting this drawable, or * {@code null} to clear the tint * @see #setTint(int) * @see #setTintMode(PorterDuff.Mode) */ public void setTintList(@Nullable ColorStateList tint) { } /** * Specifies a tint blending mode for this drawable. * <p> * Defines how this drawable's tint color should be blended into the drawable * before it is drawn to screen. Default tint mode is {@link PorterDuff.Mode#SRC_IN}. * </p> * <p class="note"><strong>Note:</strong> Setting a color filter via * {@link #setColorFilter(ColorFilter)} or * {@link #setColorFilter(int, PorterDuff.Mode)} overrides tint. * </p> * * @param tintMode A Porter-Duff blending mode * @see #setTint(int) * @see #setTintList(ColorStateList) */ public void setTintMode(@NonNull 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 @Nullable 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 position in pixels of the left bound * @param top position in pixels of the top bound * @param right position in pixels of the right bound * @param bottom position in pixels of the bottom bound * @see #getHotspotBounds(android.graphics.Rect) */ public void setHotspotBounds(int left, int top, int right, int bottom) { } /** * Populates {@code outRect} with the hotspot bounds. * * @param outRect the rect to populate with the hotspot bounds * @see #setHotspotBounds(int, int, int, int) */ public void getHotspotBounds(@NonNull Rect outRect) { outRect.set(getBounds()); } /** * Whether this drawable requests projection. * * @hide magic! */ @UnsupportedAppUsage 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; } /** * Indicates whether this drawable has at least one state spec explicitly * specifying {@link android.R.attr#state_focused}. * * <p>Note: A View uses a {@link Drawable} instance as its background and it * changes its appearance based on a state. On keyboard devices, it should * specify its {@link android.R.attr#state_focused} to make sure the user * knows which view is holding the focus.</p> * * @return {@code true} if {@link android.R.attr#state_focused} is specified * for this drawable. * * @hide */ @TestApi public boolean hasFocusStateSpecified() { 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}]. * * <p>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, <em>and</em> * true will be returned from this function. * * <p>Note: The Drawable holds a reference on to <var>stateSet</var> * until a new state array is given to it, so you must not modify this * array during that time.</p> * * @param stateSet The new set of states to be displayed. * * @return Returns true if this change in state has caused the appearance * of the Drawable to change (hence requiring an invalidate), otherwise * returns false. */ public boolean setState(@NonNull final int[] stateSet) { if (!Arrays.equals(mStateSet, stateSet)) { mStateSet = stateSet; return onStateChange(stateSet); } return false; } /** * Describes the current state, as a union of primitve states, such as * {@link android.R.attr#state_focused}, * {@link android.R.attr#state_selected}, etc. * Some drawables may modify their imagery based on the selected state. * @return An array of resource Ids describing the current state. */ public @NonNull int[] getState() { return mStateSet; } /** * If this Drawable does transition animations between states, ask that * it immediately jump to the current state and skip any active animations. */ public void jumpToCurrentState() { } /** * @return The current drawable that will be used by this drawable. For simple drawables, this * is just the drawable itself. For drawables that change state like * {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable * currently in use. */ public @NonNull Drawable getCurrent() { return this; } /** * 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. * * <p>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, <em>and</em> * 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(@IntRange(from = 0, to = 10000) 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 @IntRange(from = 0, to = 10000) 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. * * @param t the theme to apply */ public void applyTheme(@NonNull @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}. * * <p>An OPAQUE drawable is one that draws all all content within its bounds, completely * covering anything behind the drawable. A TRANSPARENT drawable is one that draws nothing * within its bounds, allowing everything behind it to show through. A TRANSLUCENT drawable * is a drawable in any other state, where the drawable will draw some, but not all, * of the content within its bounds and at least some content behind the drawable will * be visible. If the visibility of the drawable's contents cannot be determined, the * safest/best return value is TRANSLUCENT. * * <p>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. * * <p>Note that the returned value does not necessarily take into account a * custom alpha or color filter that has been applied by the client through * the {@link #setAlpha} or {@link #setColorFilter} methods. Some subclasses, * such as {@link BitmapDrawable}, {@link ColorDrawable}, and {@link GradientDrawable}, * do account for the value of {@link #setAlpha}, but the general behavior is dependent * upon the implementation of the subclass. * * @return int The opacity class of the Drawable. * * @see android.graphics.PixelFormat */ public abstract @PixelFormat.Opacity 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. * * <p>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 @PixelFormat.Opacity int resolveOpacity(@PixelFormat.Opacity int op1, @PixelFormat.Opacity 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 @Nullable 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) { // Stub method. } /** * Returns the drawable's intrinsic width. * <p> * Intrinsic width is the width at which the drawable would like to be laid * out, including any inherent padding. If the drawable has no intrinsic * width, such as a solid color, this method returns -1. * * @return the intrinsic width, or -1 if no intrinsic width */ public int getIntrinsicWidth() { return -1; } /** * Returns the drawable's intrinsic height. * <p> * Intrinsic height is the height at which the drawable would like to be * laid out, including any inherent padding. If the drawable has no * intrinsic height, such as a solid color, this method returns -1. * * @return the intrinsic height, or -1 if no intrinsic height */ 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 @NonNull Insets getOpticalInsets() { return Insets.NONE; } /** * Called to get the drawable to populate the Outline that defines its drawing area. * <p> * This method is called by the default {@link android.view.ViewOutlineProvider} to define * the outline of the View. * <p> * 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 @NonNull Drawable mutate() { return this; } /** * Clears the mutated state, allowing this drawable to be cached and * mutated again. * <p> * 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. * * @deprecated Prefer the version without an Options object. */ @Nullable public static Drawable createFromResourceStream(@Nullable Resources res, @Nullable TypedValue value, @Nullable InputStream is, @Nullable String srcName, @Nullable BitmapFactory.Options opts) { if (is == null) { return null; } if (opts == null) { return getBitmapDrawable(res, value, is); } /* 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. opts.inScreenDensity = Drawable.resolveDensity(res, 0); 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; } private static Drawable getBitmapDrawable(Resources res, TypedValue value, InputStream is) { try { ImageDecoder.Source source = null; if (value != null) { int density = Bitmap.DENSITY_NONE; if (value.density == TypedValue.DENSITY_DEFAULT) { density = DisplayMetrics.DENSITY_DEFAULT; } else if (value.density != TypedValue.DENSITY_NONE) { density = value.density; } source = ImageDecoder.createSource(res, is, density); } else { source = ImageDecoder.createSource(res, is); } return ImageDecoder.decodeDrawable(source, (decoder, info, src) -> { decoder.setAllocator(ImageDecoder.ALLOCATOR_SOFTWARE); }); } catch (IOException e) { /* do nothing. If the exception happened on decode, the drawable will be null. */ Log.e("Drawable", "Unable to decode stream: " + e); } return null; } /** * Create a drawable from an XML document. For more information on how to * create resources in XML, see * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. */ @NonNull public static Drawable createFromXml(@NonNull Resources r, @NonNull 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 * <a href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>. */ @NonNull public static Drawable createFromXml(@NonNull Resources r, @NonNull XmlPullParser parser, @Nullable Theme theme) throws XmlPullParserException, IOException { return createFromXmlForDensity(r, parser, 0, theme); } /** * Version of {@link #createFromXml(Resources, XmlPullParser, Theme)} that accepts a density * override. * @hide */ @NonNull public static Drawable createFromXmlForDensity(@NonNull Resources r, @NonNull XmlPullParser parser, int density, @Nullable Theme theme) throws XmlPullParserException, IOException { AttributeSet attrs = Xml.asAttributeSet(parser); int type; //noinspection StatementWithEmptyBody 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 = createFromXmlInnerForDensity(r, parser, attrs, density, 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. */ @NonNull public static Drawable createFromXmlInner(@NonNull Resources r, @NonNull XmlPullParser parser, @NonNull 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. */ @NonNull public static Drawable createFromXmlInner(@NonNull Resources r, @NonNull XmlPullParser parser, @NonNull AttributeSet attrs, @Nullable Theme theme) throws XmlPullParserException, IOException { return createFromXmlInnerForDensity(r, parser, attrs, 0, theme); } /** * Version of {@link #createFromXmlInner(Resources, XmlPullParser, AttributeSet, Theme)} that * accepts an override density. */ @NonNull static Drawable createFromXmlInnerForDensity(@NonNull Resources r, @NonNull XmlPullParser parser, @NonNull AttributeSet attrs, int density, @Nullable Theme theme) throws XmlPullParserException, IOException { return r.getDrawableInflater().inflateFromXmlForDensity(parser.getName(), parser, attrs, density, theme); } /** * Create a drawable from file path name. */ @Nullable public static Drawable createFromPath(String pathName) { if (pathName == null) { return null; } Trace.traceBegin(Trace.TRACE_TAG_RESOURCES, pathName); try (FileInputStream stream = new FileInputStream(pathName)) { return getBitmapDrawable(null, null, stream); } catch (IOException e) { // Do nothing; we will just return null if the FileInputStream had an error } 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(@NonNull Resources r, @NonNull XmlPullParser parser, @NonNull AttributeSet attrs) throws XmlPullParserException, IOException { inflate(r, parser, attrs, null); } /** * 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. * * @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(@NonNull Resources r, @NonNull XmlPullParser parser, @NonNull AttributeSet attrs, @Nullable Theme theme) throws XmlPullParserException, IOException { final TypedArray a = obtainAttributes(r, theme, attrs, R.styleable.Drawable); mVisible = a.getBoolean(R.styleable.Drawable_visible, mVisible); a.recycle(); } /** * Inflate a Drawable from an XML resource. * * @throws XmlPullParserException * @throws IOException */ @UnsupportedAppUsage void inflateWithAttributes(@NonNull @SuppressWarnings("unused") Resources r, @NonNull @SuppressWarnings("unused") XmlPullParser parser, @NonNull TypedArray attrs, @AttrRes int visibleAttr) throws XmlPullParserException, IOException { mVisible = attrs.getBoolean(visibleAttr, mVisible); } /** * Sets the source override density for this Drawable. If non-zero, this density is to be used * for any calls to {@link Resources#getDrawableForDensity(int, int, Theme)} or * {@link Resources#getValueForDensity(int, int, TypedValue, boolean)}. * @hide */ final void setSrcDensityOverride(int density) { mSrcDensityOverride = density; } /** * 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. * * <p> * {@link #newDrawable(Resources)} can be used as a factory to create new Drawable instances * from this ConstantState. * </p> * * Use {@link Drawable#getConstantState()} to retrieve the ConstantState of a Drawable. Calling * {@link Drawable#mutate()} on a Drawable should typically create a new ConstantState for that * Drawable. */ public static abstract class ConstantState { /** * Creates a new Drawable instance from its constant state. * <p> * <strong>Note:</strong> Using this method means density-dependent * properties, such as pixel dimensions or bitmap images, will not be * updated to match the density of the target display. To ensure * correct scaling, use {@link #newDrawable(Resources)} instead to * provide an appropriate Resources object. * * @return a new drawable object based on this constant state * @see #newDrawable(Resources) */ public abstract @NonNull Drawable newDrawable(); /** * Creates a new Drawable instance from its constant state using the * specified resources. This method should be implemented for drawables * that have density-dependent properties. * <p> * The default implementation for this method calls through to * {@link #newDrawable()}. * * @param res the resources of the context in which the drawable will * be displayed * @return a new drawable object based on this constant state */ public @NonNull Drawable newDrawable(@Nullable Resources res) { return newDrawable(); } /** * Creates a new Drawable instance from its constant state using the * specified resources and theme. This method should be implemented for * drawables that have theme-dependent properties. * <p> * The default implementation for this method calls through to * {@link #newDrawable(Resources)}. * * @param res the resources of the context in which the drawable will * be displayed * @param theme the theme of the context in which the drawable will be * displayed * @return a new drawable object based on this constant state */ public @NonNull Drawable newDrawable(@Nullable Resources res, @Nullable @SuppressWarnings("unused") Theme theme) { return newDrawable(res); } /** * Return a bit mask of configuration changes that will impact * this drawable (and thus require completely reloading it). */ public abstract @Config int getChangingConfigurations(); /** * Return whether this constant state can have a theme applied. */ public boolean canApplyTheme() { return false; } } /** * Return a {@link ConstantState} instance that holds the shared state of this Drawable. * * @return The ConstantState associated to that Drawable. * @see ConstantState * @see Drawable#mutate() */ public @Nullable ConstantState getConstantState() { return null; } private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np, Rect pad, Rect layoutBounds, String srcName) { if (np != null) { return new NinePatchDrawable(res, bm, np, pad, layoutBounds, srcName); } return new BitmapDrawable(res, bm); } /** * Ensures the tint filter is consistent with the current tint color and * mode. */ @UnsupportedAppUsage @Nullable PorterDuffColorFilter updateTintFilter(@Nullable PorterDuffColorFilter tintFilter, @Nullable ColorStateList tint, @Nullable PorterDuff.Mode tintMode) { if (tint == null || tintMode == null) { return null; } final int color = tint.getColorForState(getState(), Color.TRANSPARENT); if (tintFilter == null) { return new PorterDuffColorFilter(color, tintMode); } tintFilter.setColor(color); tintFilter.setMode(tintMode); return tintFilter; } /** * Obtains styled attributes from the theme, if available, or unstyled * resources if the theme is null. * @hide */ protected static @NonNull TypedArray obtainAttributes(@NonNull Resources res, @Nullable Theme theme, @NonNull AttributeSet set, @NonNull int[] attrs) { if (theme == null) { return res.obtainAttributes(set, attrs); } return theme.obtainStyledAttributes(set, attrs, 0, 0); } /** * Scales a floating-point pixel value from the source density to the * target density. * * @param pixels the pixel value for use in source density * @param sourceDensity the source density * @param targetDensity the target density * @return the scaled pixel value for use in target density */ static float scaleFromDensity(float pixels, int sourceDensity, int targetDensity) { return pixels * targetDensity / sourceDensity; } /** * Scales a pixel value from the source density to the target density, * optionally handling the resulting pixel value as a size rather than an * offset. * <p> * A size conversion involves rounding the base value and ensuring that * a non-zero base value is at least one pixel in size. * <p> * An offset conversion involves simply truncating the base value to an * integer. * * @param pixels the pixel value for use in source density * @param sourceDensity the source density * @param targetDensity the target density * @param isSize {@code true} to handle the resulting scaled value as a * size, or {@code false} to handle it as an offset * @return the scaled pixel value for use in target density */ static int scaleFromDensity(int pixels, int sourceDensity, int targetDensity, boolean isSize) { if (pixels == 0 || sourceDensity == targetDensity) { return pixels; } final float result = pixels * targetDensity / (float) sourceDensity; if (!isSize) { return (int) result; } final int rounded = Math.round(result); if (rounded != 0) { return rounded; } else if (pixels > 0) { return 1; } else { return -1; } } static int resolveDensity(@Nullable Resources r, int parentDensity) { final int densityDpi = r == null ? parentDensity : r.getDisplayMetrics().densityDpi; return densityDpi == 0 ? DisplayMetrics.DENSITY_DEFAULT : densityDpi; } /** * Re-throws an exception as a {@link RuntimeException} with an empty stack * trace to avoid cluttering the log. The original exception's stack trace * will still be included. * * @param cause the exception to re-throw * @throws RuntimeException */ static void rethrowAsRuntimeException(@NonNull Exception cause) throws RuntimeException { final RuntimeException e = new RuntimeException(cause); e.setStackTrace(new StackTraceElement[0]); throw e; } /** * Parses a {@link android.graphics.PorterDuff.Mode} from a tintMode * attribute's enum value. * * @hide */ @UnsupportedAppUsage public static PorterDuff.Mode parseTintMode(int value, Mode defaultMode) { switch (value) { case 3: return Mode.SRC_OVER; case 5: return Mode.SRC_IN; case 9: return Mode.SRC_ATOP; case 14: return Mode.MULTIPLY; case 15: return Mode.SCREEN; case 16: return Mode.ADD; default: return defaultMode; } } }