Java tutorial
/* * Copyright (C) 2015 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.support.v17.leanback.graphics; import android.content.res.Resources; import android.graphics.Canvas; import android.graphics.ColorFilter; import android.graphics.PixelFormat; import android.graphics.Rect; import android.graphics.drawable.Drawable; import android.support.annotation.NonNull; import android.support.v17.leanback.graphics.BoundsRule.ValueRule; import android.support.v4.graphics.drawable.DrawableCompat; import android.util.Property; import java.util.ArrayList; /** * Generic drawable class that can be composed of multiple children. Whenever the bounds changes * for this class, it updates those of its children. */ public class CompositeDrawable extends Drawable implements Drawable.Callback { static class CompositeState extends Drawable.ConstantState { final ArrayList<ChildDrawable> mChildren; CompositeState() { mChildren = new ArrayList<ChildDrawable>(); } CompositeState(CompositeState other, CompositeDrawable parent, Resources res) { final int n = other.mChildren.size(); mChildren = new ArrayList<ChildDrawable>(n); for (int k = 0; k < n; k++) { mChildren.add(new ChildDrawable(other.mChildren.get(k), parent, res)); } } @NonNull @Override public Drawable newDrawable() { return new CompositeDrawable(this); } @Override public int getChangingConfigurations() { return 0; } } CompositeState mState; boolean mMutated = false; public CompositeDrawable() { mState = new CompositeState(); } CompositeDrawable(CompositeState state) { mState = state; } @Override public ConstantState getConstantState() { return mState; } @Override public Drawable mutate() { if (!mMutated && super.mutate() == this) { mState = new CompositeState(mState, this, null); final ArrayList<ChildDrawable> children = mState.mChildren; for (int i = 0, n = children.size(); i < n; i++) { final Drawable dr = children.get(i).mDrawable; if (dr != null) { dr.mutate(); } } mMutated = true; } return this; } /** * Adds the supplied region. */ public void addChildDrawable(Drawable drawable) { mState.mChildren.add(new ChildDrawable(drawable, this)); } /** * Sets the supplied region at given index. */ public void setChildDrawableAt(int index, Drawable drawable) { mState.mChildren.set(index, new ChildDrawable(drawable, this)); } /** * Returns the {@link Drawable} for the given index. */ public Drawable getDrawable(int index) { return mState.mChildren.get(index).mDrawable; } /** * Returns the {@link ChildDrawable} at the given index. */ public ChildDrawable getChildAt(int index) { return mState.mChildren.get(index); } /** * Removes the child corresponding to the given index. */ public void removeChild(int index) { mState.mChildren.remove(index); } /** * Removes the given region. */ public void removeDrawable(Drawable drawable) { final ArrayList<ChildDrawable> children = mState.mChildren; for (int i = 0; i < children.size(); i++) { if (drawable == children.get(i).mDrawable) { children.get(i).mDrawable.setCallback(null); children.remove(i); return; } } } /** * Returns the total number of children. */ public int getChildCount() { return mState.mChildren.size(); } @Override public void draw(Canvas canvas) { final ArrayList<ChildDrawable> children = mState.mChildren; for (int i = 0; i < children.size(); i++) { children.get(i).mDrawable.draw(canvas); } } @Override protected void onBoundsChange(Rect bounds) { super.onBoundsChange(bounds); updateBounds(bounds); } @Override public void setColorFilter(ColorFilter colorFilter) { final ArrayList<ChildDrawable> children = mState.mChildren; for (int i = 0; i < children.size(); i++) { children.get(i).mDrawable.setColorFilter(colorFilter); } } @Override public int getOpacity() { return PixelFormat.UNKNOWN; } @Override public void setAlpha(int alpha) { final ArrayList<ChildDrawable> children = mState.mChildren; for (int i = 0; i < children.size(); i++) { children.get(i).mDrawable.setAlpha(alpha); } } /** * @return Alpha value between 0(inclusive) and 255(inclusive) */ @Override public int getAlpha() { final Drawable dr = getFirstNonNullDrawable(); if (dr != null) { return DrawableCompat.getAlpha(dr); } else { return 0xFF; } } final Drawable getFirstNonNullDrawable() { final ArrayList<ChildDrawable> children = mState.mChildren; for (int i = 0, n = children.size(); i < n; i++) { final Drawable dr = children.get(i).mDrawable; if (dr != null) { return dr; } } return null; } @Override public void invalidateDrawable(Drawable who) { invalidateSelf(); } @Override public void scheduleDrawable(Drawable who, Runnable what, long when) { scheduleSelf(what, when); } @Override public void unscheduleDrawable(Drawable who, Runnable what) { unscheduleSelf(what); } /** * Updates the bounds based on the {@link BoundsRule}. */ void updateBounds(Rect bounds) { final ArrayList<ChildDrawable> children = mState.mChildren; for (int i = 0; i < children.size(); i++) { ChildDrawable childDrawable = children.get(i); childDrawable.updateBounds(bounds); } } /** * Wrapper class holding a drawable object and {@link BoundsRule} to update drawable bounds * when parent bound changes. */ public static final class ChildDrawable { private final BoundsRule mBoundsRule; private final Drawable mDrawable; private final Rect adjustedBounds = new Rect(); final CompositeDrawable mParent; public ChildDrawable(Drawable drawable, CompositeDrawable parent) { this.mDrawable = drawable; this.mParent = parent; this.mBoundsRule = new BoundsRule(); drawable.setCallback(parent); } ChildDrawable(ChildDrawable orig, CompositeDrawable parent, Resources res) { final Drawable dr = orig.mDrawable; final Drawable clone; if (dr != null) { final ConstantState cs = dr.getConstantState(); if (res != null) { clone = cs.newDrawable(res); } else { clone = cs.newDrawable(); } clone.setCallback(parent); DrawableCompat.setLayoutDirection(clone, DrawableCompat.getLayoutDirection(dr)); clone.setBounds(dr.getBounds()); clone.setLevel(dr.getLevel()); } else { clone = null; } if (orig.mBoundsRule != null) { this.mBoundsRule = new BoundsRule(orig.mBoundsRule); } else { this.mBoundsRule = new BoundsRule(); } mDrawable = clone; mParent = parent; } /** * Returns the instance of {@link BoundsRule}. */ public BoundsRule getBoundsRule() { return this.mBoundsRule; } /** * Returns the {@link Drawable}. */ public Drawable getDrawable() { return mDrawable; } /** * Updates the bounds based on the {@link BoundsRule}. */ void updateBounds(Rect bounds) { mBoundsRule.calculateBounds(bounds, adjustedBounds); mDrawable.setBounds(adjustedBounds); } /** * After changing the {@link BoundsRule}, user should call this function * for the drawable to recalculate its bounds. */ public void recomputeBounds() { updateBounds(mParent.getBounds()); } /** * Implementation of {@link Property} for overrideTop attribute. */ public static final Property<CompositeDrawable.ChildDrawable, Integer> TOP_ABSOLUTE = new Property<CompositeDrawable.ChildDrawable, Integer>( Integer.class, "absoluteTop") { @Override public void set(CompositeDrawable.ChildDrawable obj, Integer value) { if (obj.getBoundsRule().top == null) { obj.getBoundsRule().top = ValueRule.absoluteValue(value); } else { obj.getBoundsRule().top.setAbsoluteValue(value); } obj.recomputeBounds(); } @Override public Integer get(CompositeDrawable.ChildDrawable obj) { if (obj.getBoundsRule().top == null) { return obj.mParent.getBounds().top; } return obj.getBoundsRule().top.getAbsoluteValue(); } }; /** * Implementation of {@link Property} for overrideBottom attribute. */ public static final Property<CompositeDrawable.ChildDrawable, Integer> BOTTOM_ABSOLUTE = new Property<CompositeDrawable.ChildDrawable, Integer>( Integer.class, "absoluteBottom") { @Override public void set(CompositeDrawable.ChildDrawable obj, Integer value) { if (obj.getBoundsRule().bottom == null) { obj.getBoundsRule().bottom = ValueRule.absoluteValue(value); } else { obj.getBoundsRule().bottom.setAbsoluteValue(value); } obj.recomputeBounds(); } @Override public Integer get(CompositeDrawable.ChildDrawable obj) { if (obj.getBoundsRule().bottom == null) { return obj.mParent.getBounds().bottom; } return obj.getBoundsRule().bottom.getAbsoluteValue(); } }; /** * Implementation of {@link Property} for overrideLeft attribute. */ public static final Property<CompositeDrawable.ChildDrawable, Integer> LEFT_ABSOLUTE = new Property<CompositeDrawable.ChildDrawable, Integer>( Integer.class, "absoluteLeft") { @Override public void set(CompositeDrawable.ChildDrawable obj, Integer value) { if (obj.getBoundsRule().left == null) { obj.getBoundsRule().left = ValueRule.absoluteValue(value); } else { obj.getBoundsRule().left.setAbsoluteValue(value); } obj.recomputeBounds(); } @Override public Integer get(CompositeDrawable.ChildDrawable obj) { if (obj.getBoundsRule().left == null) { return obj.mParent.getBounds().left; } return obj.getBoundsRule().left.getAbsoluteValue(); } }; /** * Implementation of {@link Property} for overrideRight attribute. */ public static final Property<CompositeDrawable.ChildDrawable, Integer> RIGHT_ABSOLUTE = new Property<CompositeDrawable.ChildDrawable, Integer>( Integer.class, "absoluteRight") { @Override public void set(CompositeDrawable.ChildDrawable obj, Integer value) { if (obj.getBoundsRule().right == null) { obj.getBoundsRule().right = ValueRule.absoluteValue(value); } else { obj.getBoundsRule().right.setAbsoluteValue(value); } obj.recomputeBounds(); } @Override public Integer get(CompositeDrawable.ChildDrawable obj) { if (obj.getBoundsRule().right == null) { return obj.mParent.getBounds().right; } return obj.getBoundsRule().right.getAbsoluteValue(); } }; /** * Implementation of {@link Property} for overwriting the bottom attribute of * {@link BoundsRule} associated with this {@link ChildDrawable}. This allows users to * change the bounds rules as a percentage of parent size. This is preferable over * {@see PROPERTY_TOP_ABSOLUTE} when the exact start/end position of scroll movement * isn't available at compile time. */ public static final Property<CompositeDrawable.ChildDrawable, Float> TOP_FRACTION = new Property<CompositeDrawable.ChildDrawable, Float>( Float.class, "fractionTop") { @Override public void set(CompositeDrawable.ChildDrawable obj, Float value) { if (obj.getBoundsRule().top == null) { obj.getBoundsRule().top = ValueRule.inheritFromParent(value); } else { obj.getBoundsRule().top.setFraction(value); } obj.recomputeBounds(); } @Override public Float get(CompositeDrawable.ChildDrawable obj) { if (obj.getBoundsRule().top == null) { return 0f; } return obj.getBoundsRule().top.getFraction(); } }; /** * Implementation of {@link Property} for overwriting the bottom attribute of * {@link BoundsRule} associated with this {@link ChildDrawable}. This allows users to * change the bounds rules as a percentage of parent size. This is preferable over * {@see PROPERTY_BOTTOM_ABSOLUTE} when the exact start/end position of scroll movement * isn't available at compile time. */ public static final Property<CompositeDrawable.ChildDrawable, Float> BOTTOM_FRACTION = new Property<CompositeDrawable.ChildDrawable, Float>( Float.class, "fractionBottom") { @Override public void set(CompositeDrawable.ChildDrawable obj, Float value) { if (obj.getBoundsRule().bottom == null) { obj.getBoundsRule().bottom = ValueRule.inheritFromParent(value); } else { obj.getBoundsRule().bottom.setFraction(value); } obj.recomputeBounds(); } @Override public Float get(CompositeDrawable.ChildDrawable obj) { if (obj.getBoundsRule().bottom == null) { return 1f; } return obj.getBoundsRule().bottom.getFraction(); } }; /** * Implementation of {@link Property} for overwriting the bottom attribute of * {@link BoundsRule} associated with this {@link ChildDrawable}. This allows users to * change the bounds rules as a percentage of parent size. This is preferable over * {@see PROPERTY_LEFT_ABSOLUTE} when the exact start/end position of scroll movement * isn't available at compile time. */ public static final Property<CompositeDrawable.ChildDrawable, Float> LEFT_FRACTION = new Property<CompositeDrawable.ChildDrawable, Float>( Float.class, "fractionLeft") { @Override public void set(CompositeDrawable.ChildDrawable obj, Float value) { if (obj.getBoundsRule().left == null) { obj.getBoundsRule().left = ValueRule.inheritFromParent(value); } else { obj.getBoundsRule().left.setFraction(value); } obj.recomputeBounds(); } @Override public Float get(CompositeDrawable.ChildDrawable obj) { if (obj.getBoundsRule().left == null) { return 0f; } return obj.getBoundsRule().left.getFraction(); } }; /** * Implementation of {@link Property} for overwriting the bottom attribute of * {@link BoundsRule} associated with this {@link ChildDrawable}. This allows users to * change the bounds rules as a percentage of parent size. This is preferable over * {@see PROPERTY_RIGHT_ABSOLUTE} when the exact start/end position of scroll movement * isn't available at compile time. */ public static final Property<CompositeDrawable.ChildDrawable, Float> RIGHT_FRACTION = new Property<CompositeDrawable.ChildDrawable, Float>( Float.class, "fractionRight") { @Override public void set(CompositeDrawable.ChildDrawable obj, Float value) { if (obj.getBoundsRule().right == null) { obj.getBoundsRule().right = ValueRule.inheritFromParent(value); } else { obj.getBoundsRule().right.setFraction(value); } obj.recomputeBounds(); } @Override public Float get(CompositeDrawable.ChildDrawable obj) { if (obj.getBoundsRule().right == null) { return 1f; } return obj.getBoundsRule().right.getFraction(); } }; } }