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<?xml version="1.0" encoding="utf-8"?> | |
<!-- | |
~ Copyright 2014 Chris Banes | |
~ | |
~ 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. | |
--> | |
<resources> | |
<declare-styleable name="CollapsingTitleLayout"> | |
<attr name="expandedMargin" format="reference|dimension" /> | |
<attr name="expandedTextSize" format="reference|dimension" /> | |
<attr name="collapsedTextSize" format="reference|dimension" /> | |
<attr name="minTextSize" format="reference|dimension" /> | |
<attr name="android:textColor" /> | |
</declare-styleable> | |
</resources> |
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/* | |
* Copyright 2014 Chris Banes | |
* | |
* 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 app.philm.in.view; | |
import android.content.Context; | |
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.os.Build; | |
import android.support.v4.view.ViewCompat; | |
import android.support.v7.widget.Toolbar; | |
import android.text.TextPaint; | |
import android.text.TextUtils; | |
import android.util.AttributeSet; | |
import android.util.DisplayMetrics; | |
import android.util.TypedValue; | |
import android.view.View; | |
import android.view.ViewGroup; | |
import android.widget.FrameLayout; | |
import app.philm.in.R; | |
public class CollapsingTitleLayout extends FrameLayout { | |
private static final float DEFAULT_MIN_TEXT_SIZE = 12f; // 12dp | |
// 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 static final Rect TEMP_RECT = new Rect(); | |
private Toolbar mToolbar; | |
private View mDummyView; | |
private float mScrollOffset; | |
private final Rect mToolbarContentBounds; | |
private final Rect mTextPaintBounds; | |
private final Rect mDrawnTextBounds; | |
private float mMinTextSize; | |
private float mExpandedMargin; | |
private float mRequestedExpandedTitleTextSize; | |
private float mExpandedTitleTextSize; | |
private float mRequestedCollapsedTitleTextSize; | |
private float mCollapsedTitleTextSize; | |
private float mExpandedTop; | |
private float mCollapsedTop; | |
private String mTitle; | |
private String mTitleToDraw; | |
private boolean mUseTexture; | |
private Bitmap mExpandedTitleTexture; | |
private float mTextLeft; | |
private float mTextRight; | |
private float mTextTop; | |
private float mScale; | |
private final TextPaint mTextPaint; | |
private Paint mTexturePaint; | |
public CollapsingTitleLayout(Context context) { | |
this(context, null); | |
} | |
public CollapsingTitleLayout(Context context, AttributeSet attrs) { | |
this(context, attrs, 0); | |
} | |
public CollapsingTitleLayout(Context context, AttributeSet attrs, int defStyleAttr) { | |
super(context, attrs, defStyleAttr); | |
mTextPaint = new TextPaint(); | |
mTextPaint.setAntiAlias(true); | |
mMinTextSize = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, DEFAULT_MIN_TEXT_SIZE, | |
getResources().getDisplayMetrics()); | |
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CollapsingTitleLayout); | |
mExpandedMargin = a.getDimensionPixelSize( | |
R.styleable.CollapsingTitleLayout_expandedMargin, 0); | |
mRequestedExpandedTitleTextSize = a.getDimensionPixelSize( | |
R.styleable.CollapsingTitleLayout_expandedTextSize, 0); | |
mRequestedCollapsedTitleTextSize = a.getDimensionPixelSize( | |
R.styleable.CollapsingTitleLayout_collapsedTextSize, 0); | |
mTextPaint.setColor(a.getColor( | |
R.styleable.CollapsingTitleLayout_android_textColor, Color.WHITE)); | |
final int defaultMinTextSize = (int) TypedValue | |
.applyDimension(TypedValue.COMPLEX_UNIT_DIP, DEFAULT_MIN_TEXT_SIZE, | |
getResources().getDisplayMetrics()); | |
mMinTextSize = a.getDimensionPixelSize(R.styleable.CollapsingTitleLayout_minTextSize, | |
defaultMinTextSize); | |
a.recycle(); | |
mTextPaintBounds = new Rect(); | |
mDrawnTextBounds = new Rect(); | |
mToolbarContentBounds = new Rect(); | |
setWillNotDraw(false); | |
} | |
@Override | |
public void addView(View child, int index, ViewGroup.LayoutParams params) { | |
super.addView(child, index, params); | |
if (child instanceof Toolbar) { | |
mToolbar = (Toolbar) child; | |
mDummyView = new View(getContext()); | |
mToolbar.addView(mDummyView, LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT); | |
} | |
} | |
/** | |
* 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. | |
* | |
* 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 setScrollOffset(float offset) { | |
if (offset != mScrollOffset) { | |
mScrollOffset = offset; | |
calculateOffsets(); | |
} | |
} | |
private void calculateOffsets() { | |
final float offset = mScrollOffset; | |
mTextLeft = interpolate(mExpandedMargin, mToolbarContentBounds.left, offset); | |
mTextTop = interpolate(mExpandedTop, mCollapsedTop, offset); | |
mTextRight = interpolate(getWidth() - mExpandedMargin, mToolbarContentBounds.right, offset); | |
setInterpolatedTextSize(interpolate(mExpandedTitleTextSize, | |
mCollapsedTitleTextSize, offset)); | |
ViewCompat.postInvalidateOnAnimation(this); | |
} | |
private void calculateTextBounds() { | |
final DisplayMetrics metrics = getResources().getDisplayMetrics(); | |
// First, let's calculate the expanded text size so that it fit within the bounds | |
// We make sure this value is at least our minimum text size | |
mExpandedTitleTextSize = Math.max(mMinTextSize, | |
getSingleLineTextSize(mTitle, mTextPaint, getWidth() - (mExpandedMargin * 2f), 0f, | |
mRequestedExpandedTitleTextSize, 0.5f, metrics)); | |
mTextPaint.setTextSize(mExpandedTitleTextSize); | |
mTextPaint.getTextBounds(mTitle, 0, mTitle.length(), TEMP_RECT); | |
mExpandedTop = getHeight() - TEMP_RECT.height() - mExpandedMargin; | |
// We then calculate the collapsed text size, using the same logic | |
mCollapsedTitleTextSize = Math.max(mMinTextSize, | |
getSingleLineTextSize(mTitle, mTextPaint, mToolbarContentBounds.width(), 0f, | |
mRequestedCollapsedTitleTextSize, 0.5f, metrics)); | |
mTextPaint.setTextSize(mCollapsedTitleTextSize); | |
mTextPaint.getTextBounds(mTitle, 0, mTitle.length(), TEMP_RECT); | |
mCollapsedTop = mToolbarContentBounds.centerY() - (TEMP_RECT.height() / 2f); | |
// The bounds have changed so we need to clear the texture | |
clearTexture(); | |
} | |
@Override | |
public void draw(Canvas canvas) { | |
final int saveCount = canvas.save(); | |
final int toolbarHeight = mToolbar.getHeight(); | |
canvas.clipRect(0, 0, canvas.getWidth(), | |
interpolate(canvas.getHeight(), toolbarHeight, mScrollOffset)); | |
// Now call super and let it draw the background, etc | |
super.draw(canvas); | |
if (mTitleToDraw != null) { | |
float x = mTextLeft; | |
float y = mTextTop; | |
if (!mUseTexture) { | |
// If we're not drawing a texture, we need to properly offset the text | |
x -= mDrawnTextBounds.left; | |
y -= mDrawnTextBounds.top; | |
} | |
if (DEBUG_DRAW) { | |
// Just a debug tool, which drawn a Magneta rect in the text bounds | |
canvas.drawRect(mTextLeft, mTextTop, mTextRight, | |
mTextTop + mDrawnTextBounds.height(), | |
DEBUG_DRAW_PAINT); | |
} | |
if (mScale != 1f) { | |
canvas.scale(mScale, mScale, x, y); | |
} | |
if (mUseTexture && mExpandedTitleTexture != null) { | |
// If we should use a texture, draw it instead of text | |
canvas.drawBitmap(mExpandedTitleTexture, x, y, mTexturePaint); | |
} else { | |
canvas.drawText(mTitleToDraw, x, y, mTextPaint); | |
} | |
} | |
canvas.restoreToCount(saveCount); | |
} | |
private void setInterpolatedTextSize(final float textSize) { | |
if (mTitle == null) return; | |
if (isClose(textSize, mCollapsedTitleTextSize) || isClose(textSize, mExpandedTitleTextSize) | |
|| mTitleToDraw == null) { | |
// If the text size is 'close' to being a decimal, then we use this as a sync-point. | |
// We disable our manual scaling and set the paint's text size. | |
mTextPaint.setTextSize(textSize); | |
mScale = 1f; | |
// We also use this as an opportunity to ellipsize the string | |
final CharSequence title = TextUtils.ellipsize(mTitle, mTextPaint, | |
(mTextRight - mTextLeft), | |
TextUtils.TruncateAt.END); | |
if (title != mTitleToDraw) { | |
// If the title has changed, turn it into a string | |
mTitleToDraw = title.toString(); | |
} | |
// As we've changed the text size (and possibly the text) we'll re-measure the text | |
mTextPaint.getTextBounds(mTitleToDraw, 0, mTitleToDraw.length(), mTextPaintBounds); | |
mDrawnTextBounds.set(mTextPaintBounds); | |
if (USE_SCALING_TEXTURE && isClose(textSize, mExpandedTitleTextSize)) { | |
ensureExpandedTexture(); | |
} | |
mUseTexture = false; | |
} else { | |
// We're not close to a decimal so use our canvas scaling method | |
if (mExpandedTitleTexture != null) { | |
mScale = textSize / mExpandedTitleTextSize; | |
} else { | |
mScale = textSize / mTextPaint.getTextSize(); | |
} | |
// Because we're scaling using canvas, we need to update the drawn text bounds too | |
mDrawnTextBounds.set(mTextPaintBounds); | |
mDrawnTextBounds.left *= mScale; | |
mDrawnTextBounds.top *= mScale; | |
mDrawnTextBounds.right *= mScale; | |
mDrawnTextBounds.bottom *= mScale; | |
mUseTexture = USE_SCALING_TEXTURE; | |
} | |
ViewCompat.postInvalidateOnAnimation(this); | |
} | |
private void ensureExpandedTexture() { | |
if (mExpandedTitleTexture != null) return; | |
mExpandedTitleTexture = Bitmap.createBitmap(mTextPaintBounds.width(), | |
mTextPaintBounds.height(), Bitmap.Config.ARGB_8888); | |
Canvas c = new Canvas(mExpandedTitleTexture); | |
c.drawText(mTitleToDraw, -mTextPaintBounds.left, -mTextPaintBounds.top, mTextPaint); | |
if (mTexturePaint == null) { | |
// Make sure we have a paint | |
mTexturePaint = new Paint(); | |
mTexturePaint.setAntiAlias(true); | |
mTexturePaint.setFilterBitmap(true); | |
} | |
} | |
@Override | |
protected void onLayout(boolean changed, int left, int top, int right, int bottom) { | |
super.onLayout(changed, left, top, right, bottom); | |
mToolbarContentBounds.left = mDummyView.getLeft(); | |
mToolbarContentBounds.top = mDummyView.getTop(); | |
mToolbarContentBounds.right = mDummyView.getRight(); | |
mToolbarContentBounds.bottom = mDummyView.getBottom(); | |
if (changed && mTitle != null) { | |
// If we've changed and we have a title, re-calculate everything! | |
calculateTextBounds(); | |
calculateOffsets(); | |
} | |
} | |
/** | |
* Set the title to display | |
* | |
* @param title | |
*/ | |
public void setTitle(String title) { | |
if (title == null || !title.equals(mTitle)) { | |
mTitle = title; | |
clearTexture(); | |
if (getHeight() > 0) { | |
// If we've already been laid out, calculate everything now otherwise we'll wait | |
// until a layout | |
calculateTextBounds(); | |
calculateOffsets(); | |
} | |
} | |
} | |
private void clearTexture() { | |
if (mExpandedTitleTexture != null) { | |
mExpandedTitleTexture.recycle(); | |
mExpandedTitleTexture = null; | |
} | |
} | |
/** | |
* Recursive binary search to find the best size for the text | |
* | |
* Adapted from https://github.com/grantland/android-autofittextview | |
*/ | |
private static float getSingleLineTextSize(String text, TextPaint paint, float targetWidth, | |
float low, float high, float precision, DisplayMetrics metrics) { | |
final float mid = (low + high) / 2.0f; | |
paint.setTextSize(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_PX, mid, metrics)); | |
final float maxLineWidth = paint.measureText(text); | |
if ((high - low) < precision) { | |
return low; | |
} else if (maxLineWidth > targetWidth) { | |
return getSingleLineTextSize(text, paint, targetWidth, low, mid, precision, metrics); | |
} else if (maxLineWidth < targetWidth) { | |
return getSingleLineTextSize(text, paint, targetWidth, mid, high, precision, metrics); | |
} else { | |
return mid; | |
} | |
} | |
/** | |
* Returns true if {@code value} is 'close' to it's closest decimal value. Close is currently | |
* defined as it's difference being < 0.01. | |
*/ | |
private static boolean isClose(float value, float targetValue) { | |
return Math.abs(value - targetValue) < 0.01f; | |
} | |
/** | |
* Interpolate between {@code startValue} and {@code endValue}, using {@code progress}. | |
*/ | |
private static float interpolate(float startValue, float endValue, float progress) { | |
return startValue + ((endValue - startValue) * progress); | |
} | |
} |
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<?xml version="1.0" encoding="utf-8"?> | |
<!-- | |
~ Copyright 2014 Chris Banes | |
~ | |
~ 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. | |
--> | |
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" | |
xmlns:app="http://schemas.android.com/apk/res-auto" | |
android:layout_height="match_parent" | |
android:layout_width="match_parent"> | |
<!-- Your content, maybe a ListView? --> | |
<app.philm.in.view.CollapsingTitleLayout | |
android:id="@+id/backdrop_toolbar" | |
android:layout_width="match_parent" | |
android:layout_height="wrap_content" | |
app:collapsedTextSize="16dp" | |
app:expandedTextSize="32sp" | |
app:expandedMargin="16sp" | |
android:textColor="?android:attr/textColorPrimaryInverse"> | |
<android.support.v7.widget.Toolbar | |
android:id="@+id/toolbar" | |
android:layout_height="?attr/actionBarSize" | |
android:layout_width="match_parent" /> | |
</app.philm.in.view.CollapsingTitleLayout> | |
</FrameLayout> |
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