Java tutorial
/* * Copyright (C) 2015 The Android Open Source Project * Modified 2016 by Ahmad Muzakki (modifications are marked with comments) * * 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.design.widget; import android.content.res.ColorStateList; import android.content.res.TypedArray; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Rect; import android.graphics.RectF; import android.graphics.Typeface; import android.os.Build; import android.support.annotation.ColorInt; import android.support.v4.math.MathUtils; import android.support.v4.text.TextDirectionHeuristicsCompat; import android.support.v4.view.ViewCompat; import android.support.v7.widget.TintTypedArray; import android.text.TextPaint; import android.text.TextUtils; import android.view.Gravity; import android.view.View; import android.view.animation.Interpolator; import com.simplecity.amp_library.R; @SuppressWarnings("RestrictedApi") public final class CustomCollapsingTextHelper { // Pre-JB-MR2 doesn't support HW accelerated canvas scaled text so we will workaround it // by using our own texture private static final boolean USE_SCALING_TEXTURE = Build.VERSION.SDK_INT < 18; private static final boolean DEBUG_DRAW = false; private static final Paint DEBUG_DRAW_PAINT; static { DEBUG_DRAW_PAINT = DEBUG_DRAW ? new Paint() : null; if (DEBUG_DRAW_PAINT != null) { DEBUG_DRAW_PAINT.setAntiAlias(true); DEBUG_DRAW_PAINT.setColor(Color.MAGENTA); } } private final View mView; private final Rect mExpandedBounds; private final Rect mCollapsedBounds; private final RectF mCurrentBounds; private final TextPaint mTitlePaint; private boolean mDrawTitle; private float mExpandedFraction; private int mExpandedTextGravity = Gravity.CENTER_VERTICAL; private int mCollapsedTextGravity = Gravity.CENTER_VERTICAL; private float mExpandedTextSize = 15; private float mCollapsedTextSize = 15; private ColorStateList mExpandedTitleColor; private ColorStateList mCollapsedTitleColor; private float mExpandedDrawY; private float mCollapsedDrawY; private float mExpandedDrawX; private float mCollapsedDrawX; private float mCurrentDrawX; private float mCurrentDrawY; private Typeface mCollapsedTypeface; private Typeface mExpandedTypeface; private Typeface mCurrentTypeface; private CharSequence mText; private CharSequence mTextToDraw; private boolean mIsRtl; private boolean mUseTexture; private Bitmap mExpandedTitleTexture; private Paint mTexturePaint; private float mTextureAscent; private float mTextureDescent; private float mScale; private float mCurrentTextSize; private int[] mState; private boolean mBoundsChanged; private Interpolator mPositionInterpolator; private Interpolator mTextSizeInterpolator; private float mCollapsedShadowRadius, mCollapsedShadowDx, mCollapsedShadowDy; private int mCollapsedShadowColor; private float mExpandedShadowRadius, mExpandedShadowDx, mExpandedShadowDy; private int mExpandedShadowColor; private CharSequence mSub; private float mSubScale; private float mExpandedSubSize = 50; private ColorStateList mCollapsedSubColor; private ColorStateList mExpandedSubColor; private TextPaint mSubPaint; private float mCurrentSubSize; private float mCollapsedSubSize = 25; private float mCollapsedSubY; private float mExpandedSubY; private float mCurrentSubY; public CustomCollapsingTextHelper(View view) { mView = view; mTitlePaint = new TextPaint(Paint.ANTI_ALIAS_FLAG | Paint.SUBPIXEL_TEXT_FLAG); mSubPaint = new TextPaint(Paint.ANTI_ALIAS_FLAG | Paint.SUBPIXEL_TEXT_FLAG); mCollapsedBounds = new Rect(); mExpandedBounds = new Rect(); mCurrentBounds = new RectF(); } /** * Returns true if {@code value} is 'close' to it's closest decimal value. Close is currently * defined as it's difference being < 0.001. */ private static boolean isClose(float value, float targetValue) { return Math.abs(value - targetValue) < 0.001f; } /** * Blend {@code color1} and {@code color2} using the given ratio. * * @param ratio of which to blend. 0.0 will return {@code color1}, 0.5 will give an even blend, * 1.0 will return {@code color2}. */ private static int blendColors(int color1, int color2, float ratio) { final float inverseRatio = 1f - ratio; float a = (Color.alpha(color1) * inverseRatio) + (Color.alpha(color2) * ratio); float r = (Color.red(color1) * inverseRatio) + (Color.red(color2) * ratio); float g = (Color.green(color1) * inverseRatio) + (Color.green(color2) * ratio); float b = (Color.blue(color1) * inverseRatio) + (Color.blue(color2) * ratio); return Color.argb((int) a, (int) r, (int) g, (int) b); } private static float lerp(float startValue, float endValue, float fraction, Interpolator interpolator) { if (interpolator != null) { fraction = interpolator.getInterpolation(fraction); } return AnimationUtils.lerp(startValue, endValue, fraction); } private static boolean rectEquals(Rect r, int left, int top, int right, int bottom) { return !(r.left != left || r.top != top || r.right != right || r.bottom != bottom); } public void setTextSizeInterpolator(Interpolator interpolator) { mTextSizeInterpolator = interpolator; recalculate(); } void setPositionInterpolator(Interpolator interpolator) { mPositionInterpolator = interpolator; recalculate(); } public void setExpandedBounds(int left, int top, int right, int bottom) { if (!rectEquals(mExpandedBounds, left, top, right, bottom)) { mExpandedBounds.set(left, top, right, bottom); mBoundsChanged = true; onBoundsChanged(); } } public void setCollapsedBounds(int left, int top, int right, int bottom) { if (!rectEquals(mCollapsedBounds, left, top, right, bottom)) { mCollapsedBounds.set(left, top, right, bottom); mBoundsChanged = true; onBoundsChanged(); } } void onBoundsChanged() { mDrawTitle = mCollapsedBounds.width() > 0 && mCollapsedBounds.height() > 0 && mExpandedBounds.width() > 0 && mExpandedBounds.height() > 0; } public int getExpandedTextGravity() { return mExpandedTextGravity; } public void setExpandedTextGravity(int gravity) { if (mExpandedTextGravity != gravity) { mExpandedTextGravity = gravity; recalculate(); } } public int getCollapsedTextGravity() { return mCollapsedTextGravity; } public void setCollapsedTextGravity(int gravity) { if (mCollapsedTextGravity != gravity) { mCollapsedTextGravity = gravity; recalculate(); } } public void setCollapsedTextAppearance(int resId) { TintTypedArray a = TintTypedArray.obtainStyledAttributes(mView.getContext(), resId, android.support.v7.appcompat.R.styleable.TextAppearance); if (a.hasValue(android.support.v7.appcompat.R.styleable.TextAppearance_android_textColor)) { mCollapsedTitleColor = a .getColorStateList(android.support.v7.appcompat.R.styleable.TextAppearance_android_textColor); } if (a.hasValue(android.support.v7.appcompat.R.styleable.TextAppearance_android_textSize)) { mCollapsedTextSize = a.getDimensionPixelSize( android.support.v7.appcompat.R.styleable.TextAppearance_android_textSize, (int) mCollapsedTextSize); } mCollapsedShadowColor = a .getInt(android.support.v7.appcompat.R.styleable.TextAppearance_android_shadowColor, 0); mCollapsedShadowDx = a.getFloat(android.support.v7.appcompat.R.styleable.TextAppearance_android_shadowDx, 0); mCollapsedShadowDy = a.getFloat(android.support.v7.appcompat.R.styleable.TextAppearance_android_shadowDy, 0); mCollapsedShadowRadius = a .getFloat(android.support.v7.appcompat.R.styleable.TextAppearance_android_shadowRadius, 0); a.recycle(); if (Build.VERSION.SDK_INT >= 16) { mCollapsedTypeface = readFontFamilyTypeface(resId); } recalculate(); } public void setExpandedTextAppearance(int resId) { TintTypedArray a = TintTypedArray.obtainStyledAttributes(mView.getContext(), resId, android.support.v7.appcompat.R.styleable.TextAppearance); if (a.hasValue(android.support.v7.appcompat.R.styleable.TextAppearance_android_textColor)) { mExpandedTitleColor = a .getColorStateList(android.support.v7.appcompat.R.styleable.TextAppearance_android_textColor); } if (a.hasValue(android.support.v7.appcompat.R.styleable.TextAppearance_android_textSize)) { mExpandedTextSize = a.getDimensionPixelSize( android.support.v7.appcompat.R.styleable.TextAppearance_android_textSize, (int) mExpandedTextSize); } mExpandedShadowColor = a.getInt(android.support.v7.appcompat.R.styleable.TextAppearance_android_shadowColor, 0); mExpandedShadowDx = a.getFloat(android.support.v7.appcompat.R.styleable.TextAppearance_android_shadowDx, 0); mExpandedShadowDy = a.getFloat(android.support.v7.appcompat.R.styleable.TextAppearance_android_shadowDy, 0); mExpandedShadowRadius = a .getFloat(android.support.v7.appcompat.R.styleable.TextAppearance_android_shadowRadius, 0); a.recycle(); if (Build.VERSION.SDK_INT >= 16) { mExpandedTypeface = readFontFamilyTypeface(resId); } recalculate(); } public void setCollapsedSubAppearance(int resId) { TypedArray a = mView.getContext().obtainStyledAttributes(resId, R.styleable.TextAppearance); if (a.hasValue(R.styleable.TextAppearance_android_textColor)) { mCollapsedSubColor = a.getColorStateList(R.styleable.TextAppearance_android_textColor); } if (a.hasValue(R.styleable.TextAppearance_android_textSize)) { mCollapsedSubSize = a.getDimensionPixelSize(R.styleable.TextAppearance_android_textSize, (int) mCollapsedSubSize); } a.recycle(); } public void setExpandedSubAppearance(int resId) { TintTypedArray a = TintTypedArray.obtainStyledAttributes(mView.getContext(), resId, android.support.v7.appcompat.R.styleable.TextAppearance); if (a.hasValue(android.support.v7.appcompat.R.styleable.TextAppearance_android_textColor)) { mExpandedSubColor = a .getColorStateList(android.support.v7.appcompat.R.styleable.TextAppearance_android_textColor); } if (a.hasValue(android.support.v7.appcompat.R.styleable.TextAppearance_android_textSize)) { mExpandedSubSize = a.getDimensionPixelSize( android.support.v7.appcompat.R.styleable.TextAppearance_android_textSize, (int) mExpandedSubSize); } } private Typeface readFontFamilyTypeface(int resId) { final TypedArray a = mView.getContext().obtainStyledAttributes(resId, Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN ? new int[] { android.R.attr.fontFamily } : new int[0]); try { final String family = a.getString(0); if (family != null) { return Typeface.create(family, Typeface.NORMAL); } } catch (Exception e) { throw new RuntimeException("Unable to read font family typeface: " + resId); } finally { a.recycle(); } return null; } void setTypefaces(Typeface typeface) { mCollapsedTypeface = mExpandedTypeface = typeface; recalculate(); } public Typeface getCollapsedTypeface() { return mCollapsedTypeface != null ? mCollapsedTypeface : Typeface.DEFAULT; } public void setCollapsedTypeface(Typeface typeface) { if (mCollapsedTypeface != typeface) { mCollapsedTypeface = typeface; recalculate(); } } public Typeface getExpandedTypeface() { return mExpandedTypeface != null ? mExpandedTypeface : Typeface.DEFAULT; } public void setExpandedTypeface(Typeface typeface) { if (mExpandedTypeface != typeface) { mExpandedTypeface = typeface; recalculate(); } } public final boolean setState(final int[] state) { mState = state; if (isStateful()) { recalculate(); return true; } return false; } final boolean isStateful() { return (mCollapsedTitleColor != null && mCollapsedTitleColor.isStateful()) || (mExpandedTitleColor != null && mExpandedTitleColor.isStateful()); } float getExpansionFraction() { return mExpandedFraction; } /** * Set the value indicating the current scroll value. This decides how much of the * background will be displayed, as well as the title metrics/positioning. * <p> * A value of {@code 0.0} indicates that the layout is fully expanded. * A value of {@code 1.0} indicates that the layout is fully collapsed. */ public void setExpansionFraction(float fraction) { fraction = MathUtils.clamp(fraction, 0f, 1f); if (fraction != mExpandedFraction) { mExpandedFraction = fraction; calculateCurrentOffsets(); } } float getCollapsedTextSize() { return mCollapsedTextSize; } void setCollapsedTextSize(float textSize) { if (mCollapsedTextSize != textSize) { mCollapsedTextSize = textSize; recalculate(); } } float getExpandedTextSize() { return mExpandedTextSize; } void setExpandedTextSize(float textSize) { if (mExpandedTextSize != textSize) { mExpandedTextSize = textSize; recalculate(); } } private void calculateCurrentOffsets() { calculateOffsets(mExpandedFraction); } private void calculateOffsets(final float fraction) { interpolateBounds(fraction); mCurrentDrawX = lerp(mExpandedDrawX, mCollapsedDrawX, fraction, mPositionInterpolator); mCurrentDrawY = lerp(mExpandedDrawY, mCollapsedDrawY, fraction, mPositionInterpolator); //region modification mCurrentSubY = lerp(mExpandedSubY, mCollapsedSubY, fraction, mPositionInterpolator); //endregion setInterpolatedTextSize(lerp(mExpandedTextSize, mCollapsedTextSize, fraction, mTextSizeInterpolator)); //region modification setInterpolatedSubSize(lerp(mExpandedSubSize, mCollapsedSubSize, fraction, mTextSizeInterpolator)); //endregion if (mCollapsedTitleColor != mExpandedTitleColor) { // If the collapsed and expanded text colors are different, blend them based on the // fraction mTitlePaint .setColor(blendColors(getCurrentExpandedTextColor(), getCurrentCollapsedTextColor(), fraction)); } else { mTitlePaint.setColor(getCurrentCollapsedTextColor()); } //region modification if (mCollapsedSubColor != mExpandedSubColor) { // If the collapsed and expanded text colors are different, blend them based on the // fraction mSubPaint.setColor(blendColors(getCurrentExpandedSubColor(), getCurrentCollapsedSubColor(), fraction)); } else { mSubPaint.setColor(getCurrentCollapsedSubColor()); } //endregion mTitlePaint.setShadowLayer(lerp(mExpandedShadowRadius, mCollapsedShadowRadius, fraction, null), lerp(mExpandedShadowDx, mCollapsedShadowDx, fraction, null), lerp(mExpandedShadowDy, mCollapsedShadowDy, fraction, null), blendColors(mExpandedShadowColor, mCollapsedShadowColor, fraction)); ViewCompat.postInvalidateOnAnimation(mView); } @ColorInt private int getCurrentExpandedTextColor() { if (mState != null) { return mExpandedTitleColor.getColorForState(mState, 0); } else { return mExpandedTitleColor.getDefaultColor(); } } @ColorInt private int getCurrentCollapsedTextColor() { if (mState != null) { return mCollapsedTitleColor.getColorForState(mState, 0); } else { return mCollapsedTitleColor.getDefaultColor(); } } @ColorInt private int getCurrentExpandedSubColor() { if (mState != null) { return mExpandedSubColor.getColorForState(mState, 0); } else { return mExpandedSubColor.getDefaultColor(); } } @ColorInt private int getCurrentCollapsedSubColor() { if (mState != null) { return mCollapsedSubColor.getColorForState(mState, 0); } else { return mCollapsedSubColor.getDefaultColor(); } } private void calculateBaseOffsets() { final float currentTextSize = mCurrentTextSize; // We then calculate the collapsed text size, using the same logic calculateUsingTextSize(mCollapsedTextSize); calculateUsingSubSize(mCollapsedSubSize); float textHeight = mTitlePaint.descent() - mTitlePaint.ascent(); if (!TextUtils.isEmpty(mSub)) { float subHeight = mSubPaint.descent() - mSubPaint.ascent(); float subOffset = (subHeight / 2) - mSubPaint.descent(); float offset = ((mCollapsedBounds.height() - (textHeight + subHeight)) / 3); mCollapsedDrawY = mCollapsedBounds.top + offset - mTitlePaint.ascent(); mCollapsedSubY = mCollapsedBounds.top + (offset * 2) + textHeight - mSubPaint.ascent(); } else { // title only textHeight = mTitlePaint.descent() - mTitlePaint.ascent(); float textOffset = (textHeight / 2) - mTitlePaint.descent(); mCollapsedDrawY = mCollapsedBounds.centerY() + textOffset; } mCollapsedDrawX = mCollapsedBounds.left; calculateUsingTextSize(mExpandedTextSize); calculateUsingSubSize(mExpandedSubSize); if (!TextUtils.isEmpty(mSub)) { float subHeight = mSubPaint.descent() - mSubPaint.ascent(); float subOffset = (subHeight / 2); mExpandedDrawY = mExpandedBounds.bottom + mSubPaint.ascent(); mExpandedSubY = mExpandedDrawY + subOffset - mSubPaint.ascent(); } else { // title only mExpandedDrawY = mExpandedBounds.bottom; } mExpandedDrawX = mExpandedBounds.left; // The bounds have changed so we need to clear the texture clearTexture(); // Now reset the text size back to the original setInterpolatedTextSize(currentTextSize); } private void interpolateBounds(float fraction) { mCurrentBounds.left = lerp(mExpandedBounds.left, mCollapsedBounds.left, fraction, mPositionInterpolator); mCurrentBounds.top = lerp(mExpandedDrawY, mCollapsedDrawY, fraction, mPositionInterpolator); mCurrentBounds.right = lerp(mExpandedBounds.right, mCollapsedBounds.right, fraction, mPositionInterpolator); mCurrentBounds.bottom = lerp(mExpandedBounds.bottom, mCollapsedBounds.bottom, fraction, mPositionInterpolator); } public void draw(Canvas canvas) { final int saveCount = canvas.save(); if (mTextToDraw != null && mDrawTitle) { float x = mCurrentDrawX; float y = mCurrentDrawY; float subY = mCurrentSubY; final boolean drawTexture = mUseTexture && mExpandedTitleTexture != null; final float ascent; final float descent; if (drawTexture) { ascent = mTextureAscent * mScale; descent = mTextureDescent * mScale; } else { ascent = mTitlePaint.ascent() * mScale; descent = mTitlePaint.descent() * mScale; } if (DEBUG_DRAW) { // Just a debug tool, which drawn a magenta rect in the text bounds canvas.drawRect(mCurrentBounds.left, y + ascent, mCurrentBounds.right, y + descent, DEBUG_DRAW_PAINT); } if (drawTexture) { y += ascent; } //region modification final int saveCountSub = canvas.save(); if (mSub != null) { if (mSubScale != 1f) { canvas.scale(mSubScale, mSubScale, x, subY); } canvas.drawText(mSub, 0, mSub.length(), x, subY, mSubPaint); canvas.restoreToCount(saveCountSub); } //endregion if (mScale != 1f) { canvas.scale(mScale, mScale, x, y); } if (drawTexture) { // If we should use a texture, draw it instead of text canvas.drawBitmap(mExpandedTitleTexture, x, y, mTexturePaint); } else { canvas.drawText(mTextToDraw, 0, mTextToDraw.length(), x, y, mTitlePaint); } } canvas.restoreToCount(saveCount); } private boolean calculateIsRtl(CharSequence text) { final boolean defaultIsRtl = ViewCompat.getLayoutDirection(mView) == ViewCompat.LAYOUT_DIRECTION_RTL; return (defaultIsRtl ? TextDirectionHeuristicsCompat.FIRSTSTRONG_RTL : TextDirectionHeuristicsCompat.FIRSTSTRONG_LTR).isRtl(text, 0, text.length()); } private void setInterpolatedTextSize(float textSize) { calculateUsingTextSize(textSize); // Use our texture if the scale isn't 1.0 mUseTexture = USE_SCALING_TEXTURE && mScale != 1f; if (mUseTexture) { // Make sure we have an expanded texture if needed ensureExpandedTexture(); } ViewCompat.postInvalidateOnAnimation(mView); } //region modification private void setInterpolatedSubSize(float textSize) { calculateUsingSubSize(textSize); ViewCompat.postInvalidateOnAnimation(mView); } //endregion private void calculateUsingTextSize(final float textSize) { if (mText == null) return; final float collapsedWidth = mCollapsedBounds.width(); final float expandedWidth = mExpandedBounds.width(); final float availableWidth; final float newTextSize; boolean updateDrawText = false; if (isClose(textSize, mCollapsedTextSize)) { newTextSize = mCollapsedTextSize; mScale = 1f; if (mCurrentTypeface != mCollapsedTypeface) { mCurrentTypeface = mCollapsedTypeface; updateDrawText = true; } availableWidth = collapsedWidth; } else { newTextSize = mExpandedTextSize; if (mCurrentTypeface != mExpandedTypeface) { mCurrentTypeface = mExpandedTypeface; updateDrawText = true; } if (isClose(textSize, mExpandedTextSize)) { // If we're close to the expanded text size, snap to it and use a scale of 1 mScale = 1f; } else { // Else, we'll scale down from the expanded text size mScale = textSize / mExpandedTextSize; } final float textSizeRatio = mCollapsedTextSize / mExpandedTextSize; // This is the size of the expanded bounds when it is scaled to match the // collapsed text size final float scaledDownWidth = expandedWidth * textSizeRatio; if (scaledDownWidth > collapsedWidth) { // If the scaled down size is larger than the actual collapsed width, we need to // cap the available width so that when the expanded text scales down, it matches // the collapsed width availableWidth = Math.min(collapsedWidth / textSizeRatio, expandedWidth); } else { // Otherwise we'll just use the expanded width availableWidth = expandedWidth; } } if (availableWidth > 0) { updateDrawText = (mCurrentTextSize != newTextSize) || mBoundsChanged || updateDrawText; mCurrentTextSize = newTextSize; mBoundsChanged = false; } if (mTextToDraw == null || updateDrawText) { mTitlePaint.setTextSize(mCurrentTextSize); mTitlePaint.setTypeface(mCurrentTypeface); // Use linear text scaling if we're scaling the canvas mTitlePaint.setLinearText(mScale != 1f); // If we don't currently have text to draw, or the text size has changed, ellipsize... final CharSequence title = TextUtils.ellipsize(mText, mTitlePaint, availableWidth, TextUtils.TruncateAt.END); if (!TextUtils.equals(title, mTextToDraw)) { mTextToDraw = title; mIsRtl = calculateIsRtl(mTextToDraw); } } } private void calculateUsingSubSize(final float subSize) { if (mSub == null) return; final float collapsedWidth = mCollapsedBounds.width(); final float expandedWidth = mExpandedBounds.width(); final float availableWidth; final float newSubSize; boolean updateDrawText = false; if (isClose(subSize, mCollapsedSubSize)) { newSubSize = mCollapsedSubSize; mSubScale = 1f; availableWidth = collapsedWidth; } else { newSubSize = mExpandedSubSize; if (isClose(subSize, mExpandedSubSize)) { // If we're close to the expanded text size, snap to it and use a scale of 1 mSubScale = 1f; } else { // Else, we'll scale down from the expanded text size mSubScale = subSize / mExpandedSubSize; } final float subSizeRatio = mCollapsedSubSize / mExpandedSubSize; // This is the size of the expanded bounds when it is scaled to match the // collapsed text size final float scaledDownWidth = expandedWidth * subSizeRatio; if (scaledDownWidth > collapsedWidth) { // If the scaled down size is larger than the actual collapsed width, we need to // cap the available width so that when the expanded text scales down, it matches // the collapsed width availableWidth = Math.min(collapsedWidth / subSizeRatio, expandedWidth); } else { // Otherwise we'll just use the expanded width availableWidth = expandedWidth; } } if (availableWidth > 0) { updateDrawText = (mCurrentSubSize != newSubSize) || mBoundsChanged || updateDrawText; mCurrentSubSize = newSubSize; mBoundsChanged = false; } if (updateDrawText) { mSubPaint.setTextSize(mCurrentSubSize); mSubPaint.setTypeface(mCurrentTypeface); // Use linear text scaling if we're scaling the canvas mSubPaint.setLinearText(mSubScale != 1f); } } private void ensureExpandedTexture() { if (mExpandedTitleTexture != null || mExpandedBounds.isEmpty() || TextUtils.isEmpty(mTextToDraw)) { return; } calculateOffsets(0f); mTextureAscent = mTitlePaint.ascent(); mTextureDescent = mTitlePaint.descent(); final int w = Math.round(mTitlePaint.measureText(mTextToDraw, 0, mTextToDraw.length())); final int h = Math.round(mTextureDescent - mTextureAscent); if (w <= 0 || h <= 0) { return; // If the width or height are 0, return } mExpandedTitleTexture = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888); Canvas c = new Canvas(mExpandedTitleTexture); c.drawText(mTextToDraw, 0, mTextToDraw.length(), 0, h - mTitlePaint.descent(), mTitlePaint); if (mTexturePaint == null) { // Make sure we have a paint mTexturePaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG); } } public void recalculate() { if (mView.getHeight() > 0 && mView.getWidth() > 0) { // If we've already been laid out, calculate everything now otherwise we'll wait // until a layout calculateBaseOffsets(); calculateCurrentOffsets(); } } public CharSequence getText() { return mText; } /** * Set the title to display * * @param text */ public void setText(CharSequence text) { if (text == null || !text.equals(mText)) { mText = text; mTextToDraw = null; clearTexture(); recalculate(); } } //region modification public void setSubtitle(CharSequence text) { if (text == null || !text.equals(mSub)) { mSub = text; clearTexture(); recalculate(); } } //endregion private void clearTexture() { if (mExpandedTitleTexture != null) { mExpandedTitleTexture.recycle(); mExpandedTitleTexture = null; } } ColorStateList getExpandedTextColor() { return mExpandedTitleColor; } ColorStateList getExpandedSubColor() { return mExpandedSubColor; } public void setExpandedTextColor(ColorStateList textColor) { if (mExpandedTitleColor != textColor) { mExpandedTitleColor = textColor; recalculate(); } } ColorStateList getCollapsedTextColor() { return mCollapsedTitleColor; } public void setCollapsedTextColor(ColorStateList textColor) { if (mCollapsedTitleColor != textColor) { mCollapsedTitleColor = textColor; recalculate(); } } ColorStateList getCollapsedSubColor() { return mCollapsedSubColor; } public void setCollapsedSubColor(ColorStateList textColor) { if (mCollapsedSubColor != textColor) { mCollapsedSubColor = textColor; recalculate(); } } }