pl.motyczko.scrollheader.PagerSlidingTabStrip.java Source code

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/*
 * Copyright (C) 2013 Andreas Stuetz <andreas.stuetz@gmail.com>
 *
 * 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 pl.motyczko.scrollheader;

import android.annotation.SuppressLint;
import android.app.ActionBar;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.PorterDuff;
import android.graphics.Typeface;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.LayerDrawable;
import android.os.Build;
import android.os.Parcel;
import android.os.Parcelable;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.text.Spannable;
import android.text.SpannableString;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.util.SparseArray;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.view.animation.AccelerateInterpolator;
import android.view.animation.AnimationUtils;
import android.view.animation.Interpolator;
import android.widget.HorizontalScrollView;
import android.widget.ImageButton;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.nineoldandroids.animation.Animator;
import com.nineoldandroids.animation.ObjectAnimator;
import com.nineoldandroids.animation.ValueAnimator;

import java.util.Locale;

import pl.motyczko.scrollheader.drawables.BlurDrawable;
import pl.motyczko.scrollheader.drawables.CircleFramedDrawable;
import pl.motyczko.scrollheader.drawables.KenBurnsDrawable;
import pl.motyczko.scrollheader.helpers.AlphaForegroundColorSpan;
import pl.motyczko.scrollheader.helpers.ArgbEvaluator;
import pl.motyczko.scrollheader.helpers.PageScrollHelper;
import pl.motyczko.scrollheader.helpers.PageScrollListener;

/**
 * TODO: extend from ScrollHeader and add tabs as container view
 */
public class PagerSlidingTabStrip extends HorizontalScrollView {
    private static final String LOG_TAG = "PagerSlidingTabStrip";
    private int mIconTopOffset = 0;

    private Matrix mDrawMatrix;

    private class Coordinate {
        public float y = 0.0f;
    }

    public interface IconTabProvider {
        public int getPageIconResId(int position);
    }

    // @formatter:off
    private static final int[] ATTRS = new int[] { android.R.attr.textSize, android.R.attr.textColor };
    // @formatter:on

    private SparseArray<Coordinate> mCoordinates;
    private PageScrollHelper mPageScrollHelper;
    private int mMinHeight = Integer.MIN_VALUE;

    private AnimatorListener mAnimatorListener = new AnimatorListener();

    private LinearLayout.LayoutParams defaultTabLayoutParams;
    private LinearLayout.LayoutParams expandedTabLayoutParams;

    private final PageListener pageListener = new PageListener();
    public OnPageChangeListener mDelegatePageListener;

    private LinearLayout tabsContainer;
    private ViewPager pager;

    private boolean mIsAnimating = false;

    private int tabCount;

    private int currentPosition = 0;
    private float currentPositionOffset = 0f;

    private Paint rectPaint;
    private Paint dividerPaint;

    private int indicatorColor = 0xFF666666;
    private int underlineColor = 0x1A000000;
    private int dividerColor = 0x1A000000;

    private boolean shouldExpand = false;
    private boolean textAllCaps = true;

    private int scrollOffset = 52;
    private int indicatorHeight = 8;
    private int underlineHeight = 2;
    private int tabStripHeight = 48;
    private int dividerPadding = 12;
    private int tabPadding = 24;
    private int dividerWidth = 1;

    private int tabTextSize = 12;
    private int tabTextColor = 0xFF666666;
    private Typeface tabTypeface = null;
    private int tabTypefaceStyle = Typeface.BOLD;

    private int lastScrollX = 0;

    private int tabBackgroundResId = R.drawable.background_tab;

    private Locale locale;

    private boolean mParallaxForBackground = true;

    private int mFrameColor = 0xffffffff;
    private float mStrokeWidth = 2;
    private int mFrameShadowColor = 0x80000000;
    private float mShadowRadius = 6;
    private int mHighlightColor = 0xffffffff;
    private boolean mKenBurnsEffect = false;
    private Drawable mViewBackground;
    private ActionBar mActionBar;
    private Interpolator mActionBarTitleInterpolator;

    private final PageListener mPageScrollListener = new PageListener();

    private Paint mPaint = new Paint();
    private boolean mBlurBackground = false;
    private boolean mKenBurnsInitialized;
    private Drawable mIcon;
    private int mIconSize = 80;
    private int mActionBarIconSize = 48;
    private SpannableString mSpannableString;
    private AlphaForegroundColorSpan mAlphaForegroundColorSpan;

    private int mOverlayColorExpanded = 0x00000000;
    private int mOverlayColorCollapsed = 0x00000000;

    private ArgbEvaluator mColorEvaluator = new ArgbEvaluator();

    public PagerSlidingTabStrip(Context context) {
        this(context, null);
    }

    public PagerSlidingTabStrip(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public PagerSlidingTabStrip(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        setFillViewport(true);
        setWillNotDraw(false);

        DisplayMetrics dm = getResources().getDisplayMetrics();

        scrollOffset = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, scrollOffset, dm);
        indicatorHeight = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, indicatorHeight, dm);
        underlineHeight = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, underlineHeight, dm);
        dividerPadding = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dividerPadding, dm);
        tabPadding = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, tabPadding, dm);
        dividerWidth = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_PX, dividerWidth, dm);
        tabTextSize = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, tabTextSize, dm);
        tabStripHeight = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, tabStripHeight, dm);
        mMinHeight = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, mMinHeight, dm);
        mIconSize = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, mIconSize, dm);
        mStrokeWidth = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, mStrokeWidth, dm);
        mShadowRadius = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, mShadowRadius, dm);
        mActionBarIconSize = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, mActionBarIconSize, dm);

        // get system attrs (android:textSize and android:textColor)

        TypedArray a = context.obtainStyledAttributes(attrs, ATTRS);

        tabTextSize = a.getDimensionPixelSize(0, tabTextSize);
        tabTextColor = a.getColor(1, tabTextColor);

        a.recycle();

        // get custom attrs

        a = context.obtainStyledAttributes(attrs, R.styleable.PagerSlidingTabStrip);

        indicatorColor = a.getColor(R.styleable.PagerSlidingTabStrip_indicatorColor, indicatorColor);
        underlineColor = a.getColor(R.styleable.PagerSlidingTabStrip_underlineColor, underlineColor);
        dividerColor = a.getColor(R.styleable.PagerSlidingTabStrip_dividerColor, dividerColor);
        tabTextColor = a.getColor(R.styleable.PagerSlidingTabStrip_tabTextColor, tabTextColor);
        indicatorHeight = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_indicatorHeight,
                indicatorHeight);
        underlineHeight = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_underlineHeight,
                underlineHeight);
        tabStripHeight = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_tabStripHeight, tabStripHeight);
        mMinHeight = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_android_minHeight, mMinHeight);
        dividerPadding = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_dividerPadding, dividerPadding);
        tabPadding = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_tabPaddingLeftRight, tabPadding);
        tabBackgroundResId = a.getResourceId(R.styleable.PagerSlidingTabStrip_tabBackground, tabBackgroundResId);
        shouldExpand = a.getBoolean(R.styleable.PagerSlidingTabStrip_shouldExpand, shouldExpand);
        scrollOffset = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_scrollOffset, scrollOffset);
        textAllCaps = a.getBoolean(R.styleable.PagerSlidingTabStrip_textAllCaps, textAllCaps);
        mBlurBackground = a.getBoolean(R.styleable.PagerSlidingTabStrip_blurBackground, mBlurBackground);
        mKenBurnsEffect = a.getBoolean(R.styleable.PagerSlidingTabStrip_kenBurnsEffect, mKenBurnsEffect);
        mParallaxForBackground = a.getBoolean(R.styleable.PagerSlidingTabStrip_parallaxEffect,
                mParallaxForBackground);
        mIconSize = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_iconSize, mIconSize);
        mIconTopOffset = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_iconTopOffset, mIconTopOffset);
        mIcon = a.getDrawable(R.styleable.PagerSlidingTabStrip_android_icon);
        mFrameColor = a.getColor(R.styleable.PagerSlidingTabStrip_frameColor, mFrameColor);
        mStrokeWidth = a.getDimension(R.styleable.PagerSlidingTabStrip_strokeWidth, mStrokeWidth);
        mFrameShadowColor = a.getColor(R.styleable.PagerSlidingTabStrip_frameShadowColor, mFrameShadowColor);
        mShadowRadius = a.getDimension(R.styleable.PagerSlidingTabStrip_shadowRadius, mShadowRadius);
        mHighlightColor = a.getColor(R.styleable.PagerSlidingTabStrip_highlightColor, mHighlightColor);
        mOverlayColorCollapsed = a.getColor(R.styleable.PagerSlidingTabStrip_overlayColorCollapsed,
                mOverlayColorCollapsed);
        mOverlayColorExpanded = a.getColor(R.styleable.PagerSlidingTabStrip_overlayColorExpanded,
                mOverlayColorExpanded);

        a.recycle();

        rectPaint = new Paint();
        rectPaint.setAntiAlias(true);
        rectPaint.setStyle(Style.FILL);

        dividerPaint = new Paint();
        dividerPaint.setAntiAlias(true);
        dividerPaint.setStrokeWidth(dividerWidth);

        defaultTabLayoutParams = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,
                LayoutParams.MATCH_PARENT);
        expandedTabLayoutParams = new LinearLayout.LayoutParams(0, LayoutParams.MATCH_PARENT, 1.0f);

        if (locale == null) {
            locale = getResources().getConfiguration().locale;
        }

        tabsContainer = new LinearLayout(context);
        tabsContainer.setOrientation(LinearLayout.HORIZONTAL);
        HorizontalScrollView.LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT, tabStripHeight);
        lp.gravity = Gravity.BOTTOM;
        tabsContainer.setLayoutParams(lp);
        addView(tabsContainer);

        setupIcon();

        a.recycle();
        mPageScrollHelper = new PageScrollHelper(this);
        mPageScrollHelper.setPageScrollListener(mPageScrollListener);

        setupBackground();
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();

        getParent().requestDisallowInterceptTouchEvent(true);
        View parent = (View) getParent();
        if (parent instanceof ViewPager)
            setViewPager((ViewPager) parent);
    }

    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        if (mViewBackground instanceof KenBurnsDrawable)
            ((KenBurnsDrawable) mViewBackground).stopAnimation();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        mPageScrollHelper.setupViews();
    }

    @Override
    public void onRestoreInstanceState(Parcelable state) {
        SavedState savedState = (SavedState) state;
        super.onRestoreInstanceState(savedState.getSuperState());
        currentPosition = savedState.currentPosition;
        requestLayout();
    }

    @Override
    public Parcelable onSaveInstanceState() {
        Parcelable superState = super.onSaveInstanceState();
        SavedState savedState = new SavedState(superState);
        savedState.currentPosition = currentPosition;
        return savedState;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        drawBackground(canvas);
        updateActionBar();
        drawIcon(canvas);
        drawTabs(canvas);
    }

    public void setViewPager(ViewPager pager) {
        this.pager = pager;
        mPageScrollHelper = new PageScrollHelper(pager, this);
        mPageScrollHelper.setPageScrollListener(pageListener);

        if (pager.getAdapter() == null) {
            throw new IllegalStateException("ViewPager does not have adapter instance.");
        }

        notifyDataSetChanged();
    }

    public void notifyDataSetChanged() {
        tabsContainer.removeAllViews();
        mCoordinates = new SparseArray<Coordinate>();
        int pageCount = pager.getAdapter().getCount();
        tabCount = pager.getAdapter().getCount();

        for (int i = 0; i < tabCount; i++) {

            if (pager.getAdapter() instanceof IconTabProvider) {
                addIconTab(i, ((IconTabProvider) pager.getAdapter()).getPageIconResId(i));
            } else {
                addTextTab(i, pager.getAdapter().getPageTitle(i).toString());
            }

        }

        updateTabStyles();

        getViewTreeObserver().addOnGlobalLayoutListener(new GlobalLayoutListener());
    }

    private void addTextTab(final int position, String title) {

        TextView tab = new TextView(getContext());
        tab.setText(title);
        tab.setGravity(Gravity.CENTER);
        tab.setSingleLine();

        addTab(position, tab);
    }

    private void addIconTab(final int position, int resId) {

        ImageButton tab = new ImageButton(getContext());
        tab.setImageResource(resId);

        addTab(position, tab);

    }

    private void addTab(final int position, View tab) {
        tab.setFocusable(true);
        tab.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                pager.setCurrentItem(position);
            }
        });

        tab.setPadding(tabPadding, 0, tabPadding, 0);
        tabsContainer.addView(tab, position, shouldExpand ? expandedTabLayoutParams : defaultTabLayoutParams);
    }

    private void updateTabStyles() {
        for (int i = 0; i < tabCount; i++) {
            View v = tabsContainer.getChildAt(i);

            v.setBackgroundResource(tabBackgroundResId);

            if (!(v instanceof TextView))
                continue;

            TextView tab = (TextView) v;
            tab.setTextSize(TypedValue.COMPLEX_UNIT_PX, tabTextSize);
            tab.setTypeface(tabTypeface, tabTypefaceStyle);
            tab.setTextColor(tabTextColor);

            // setAllCaps() is only available from API 14, so the upper case is made manually if we are on a
            // pre-ICS-build
            if (textAllCaps) {
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
                    tab.setAllCaps(true);
                } else {
                    tab.setText(tab.getText().toString().toUpperCase(locale));
                }
            }
        }
    }

    private void scrollToChild(int position, int offset) {
        if (tabCount == 0) {
            return;
        }

        int newScrollX = tabsContainer.getChildAt(position).getLeft() + offset;

        if (position > 0 || offset > 0) {
            newScrollX -= scrollOffset;
        }

        if (newScrollX != lastScrollX) {
            lastScrollX = newScrollX;
            scrollTo(newScrollX, 0);
        }
    }

    private void drawTabs(Canvas canvas) {
        canvas.save();
        canvas.translate(0, getHeight() - tabsContainer.getHeight());
        if (isInEditMode() || tabCount == 0) {
            return;
        }

        final int height = tabsContainer.getHeight();

        // draw indicator line

        rectPaint.setColor(indicatorColor);

        // default: line below current tab
        View currentTab = tabsContainer.getChildAt(currentPosition);
        float lineLeft = currentTab.getLeft();
        float lineRight = currentTab.getRight();

        // if there is an offset, start interpolating left and right coordinates between current and next tab
        if (currentPositionOffset > 0f && currentPosition < tabCount - 1) {

            View nextTab = tabsContainer.getChildAt(currentPosition + 1);
            final float nextTabLeft = nextTab.getLeft();
            final float nextTabRight = nextTab.getRight();

            lineLeft = (currentPositionOffset * nextTabLeft + (1f - currentPositionOffset) * lineLeft);
            lineRight = (currentPositionOffset * nextTabRight + (1f - currentPositionOffset) * lineRight);
        }

        canvas.drawRect(lineLeft, height - indicatorHeight, lineRight, height, rectPaint);

        // draw underline

        rectPaint.setColor(underlineColor);
        canvas.drawRect(0, height - underlineHeight, tabsContainer.getWidth(), height, rectPaint);

        // draw divider

        dividerPaint.setColor(dividerColor);
        for (int i = 0; i < tabCount - 1; i++) {
            View tab = tabsContainer.getChildAt(i);
            canvas.drawLine(tab.getRight(), dividerPadding, tab.getRight(), height - dividerPadding, dividerPaint);
        }

        canvas.restore();
    }

    public void setIndicatorColor(int indicatorColor) {
        this.indicatorColor = indicatorColor;
        invalidate();
    }

    public void setIndicatorColorResource(int resId) {
        this.indicatorColor = getResources().getColor(resId);
        invalidate();
    }

    public int getIndicatorColor() {
        return this.indicatorColor;
    }

    public void setIndicatorHeight(int indicatorLineHeightPx) {
        this.indicatorHeight = indicatorLineHeightPx;
        invalidate();
    }

    public int getIndicatorHeight() {
        return indicatorHeight;
    }

    public void setUnderlineColor(int underlineColor) {
        this.underlineColor = underlineColor;
        invalidate();
    }

    public void setUnderlineColorResource(int resId) {
        this.underlineColor = getResources().getColor(resId);
        invalidate();
    }

    public int getUnderlineColor() {
        return underlineColor;
    }

    public void setDividerColor(int dividerColor) {
        this.dividerColor = dividerColor;
        invalidate();
    }

    public void setDividerColorResource(int resId) {
        this.dividerColor = getResources().getColor(resId);
        invalidate();
    }

    public int getDividerColor() {
        return dividerColor;
    }

    public void setUnderlineHeight(int underlineHeightPx) {
        this.underlineHeight = underlineHeightPx;
        invalidate();
    }

    public int getUnderlineHeight() {
        return underlineHeight;
    }

    public void setDividerPadding(int dividerPaddingPx) {
        this.dividerPadding = dividerPaddingPx;
        invalidate();
    }

    public int getDividerPadding() {
        return dividerPadding;
    }

    public void setScrollOffset(int scrollOffsetPx) {
        this.scrollOffset = scrollOffsetPx;
        invalidate();
    }

    public int getScrollOffset() {
        return scrollOffset;
    }

    public void setShouldExpand(boolean shouldExpand) {
        this.shouldExpand = shouldExpand;
        requestLayout();
    }

    public boolean getShouldExpand() {
        return shouldExpand;
    }

    public boolean isTextAllCaps() {
        return textAllCaps;
    }

    public void setAllCaps(boolean textAllCaps) {
        this.textAllCaps = textAllCaps;
    }

    public void setTextSize(int textSizePx) {
        this.tabTextSize = textSizePx;
        updateTabStyles();
    }

    public int getTextSize() {
        return tabTextSize;
    }

    public void setTextColor(int textColor) {
        this.tabTextColor = textColor;
        updateTabStyles();
    }

    public void setTextColorResource(int resId) {
        this.tabTextColor = getResources().getColor(resId);
        updateTabStyles();
    }

    public int getTextColor() {
        return tabTextColor;
    }

    public void setTypeface(Typeface typeface, int style) {
        this.tabTypeface = typeface;
        this.tabTypefaceStyle = style;
        updateTabStyles();
    }

    public void setTabBackground(int resId) {
        this.tabBackgroundResId = resId;
    }

    public int getTabBackground() {
        return tabBackgroundResId;
    }

    public void setTabPaddingLeftRight(int paddingPx) {
        this.tabPadding = paddingPx;
        updateTabStyles();
    }

    public int getTabPaddingLeftRight() {
        return tabPadding;
    }

    protected boolean verifyDrawable(Drawable who) {
        return who == mViewBackground;
    }

    private void calculateBackgroundBounds() {
        mDrawMatrix = new Matrix();
        int dwidth = mViewBackground.getIntrinsicWidth();
        int dheight = mViewBackground.getIntrinsicHeight();

        int vwidth = getWidth();
        int vheight = getHeight();

        mViewBackground.setBounds(0, 0, dwidth, dheight);

        float scale;
        float dx = 0, dy = 0;

        if (dwidth * vheight > vwidth * dheight) {
            scale = (float) vheight / (float) dheight;
            dx = (vwidth - dwidth * scale) * 0.5f;
        } else {
            scale = (float) vwidth / (float) dwidth;
            dy = (vheight - dheight * scale) * 0.5f;
        }

        mDrawMatrix.setScale(scale, scale);
        mDrawMatrix.postTranslate((int) (dx + 0.5f), (int) (dy + 0.5f));
    }

    private void drawBackground(Canvas canvas) {
        if (mViewBackground == null)
            return;

        if (mViewBackground instanceof KenBurnsDrawable && !((KenBurnsDrawable) mViewBackground).isAnimating()) {
            mViewBackground.setBounds(0, 0, getWidth(), getHeight());
            ((KenBurnsDrawable) mViewBackground).animate();
            mKenBurnsInitialized = true;
        }
        if (mDrawMatrix == null && !(mViewBackground instanceof KenBurnsDrawable)) {
            calculateBackgroundBounds();
        }
        int saveCount = canvas.getSaveCount();
        canvas.save();
        float translation = mParallaxForBackground ? getTranslationY() / 2 : 0;
        canvas.translate(getScrollX(), getScrollY() - translation);
        if (mDrawMatrix != null)
            canvas.concat(mDrawMatrix);

        float fraction = Math.abs(getTranslationY() / getAllowedVerticalScrollLength());
        int color = (Integer) mColorEvaluator.evaluate(fraction, mOverlayColorExpanded, mOverlayColorCollapsed);
        mViewBackground.setColorFilter(color, PorterDuff.Mode.SRC_ATOP);
        mViewBackground.draw(canvas);
        canvas.restoreToCount(saveCount);
    }

    private void drawIcon(Canvas canvas) {
        if (mIcon == null)
            return;
        canvas.save();
        float translationX = calculateIconTranslationX();
        float translationY = calculateIconTranslationY();
        canvas.translate(translationX, translationY);
        float scale = calculateIconScale();
        canvas.scale(scale, scale);
        mIcon.draw(canvas);
        canvas.restore();
    }

    private void updateActionBar() {
        float fraction = Math.abs(getTranslationY() / getAllowedVerticalScrollLength());
        if (mSpannableString == null)
            mSpannableString = new SpannableString(mActionBar.getTitle());
        mAlphaForegroundColorSpan.setAlpha(mActionBarTitleInterpolator.getInterpolation(fraction));
        mSpannableString.setSpan(mAlphaForegroundColorSpan, 0, mSpannableString.length(),
                Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
        mActionBar.setTitle(mSpannableString);
    }

    private float calculateIconTranslationX() {
        int width = getWidth();

        float fraction = Math.abs(getTranslationY() / getAllowedVerticalScrollLength());

        return getScrollX() + (1 - fraction) * (width / 2 - mIconSize / 2);
    }

    private float calculateIconTranslationY() {
        int height = getHeight();
        float iconScale = calculateIconScale();
        float fraction = Math.abs(getTranslationY() / getAllowedVerticalScrollLength());
        return fraction * mIconTopOffset + (1 - fraction) * (height / 2 - mIconSize * iconScale / 2)
                - getTranslationY();
    }

    private float calculateIconScale() {
        float fraction = Math.abs(getTranslationY() / getAllowedVerticalScrollLength());
        float minSize = (float) mActionBarIconSize / (float) mIconSize;
        float scale = 1 - (1 - minSize) * fraction;
        return scale;
    }

    public void setActionBar(ActionBar actionBar) {
        if (mIcon == null)
            return;

        mActionBar = actionBar;
        if (mActionBar == null)
            return;

        mActionBar.setIcon(R.drawable.transparent_actionbar_icon);
        mActionBar.setLogo(R.drawable.transparent_actionbar_icon);
        mAlphaForegroundColorSpan = new AlphaForegroundColorSpan(0xffffffff);
        mActionBarTitleInterpolator = new AccelerateInterpolator();
    }

    public void setMinHeight(int minHeight) {
        mMinHeight = minHeight;
    }

    public void setParallax(boolean parallax) {
        mParallaxForBackground = parallax;
    }

    @Override
    public ViewGroup.LayoutParams getLayoutParams() {
        ViewGroup.LayoutParams lp = super.getLayoutParams();
        if (!(lp instanceof ViewPager.LayoutParams))
            return lp;

        ViewPager.LayoutParams vplp = (ViewPager.LayoutParams) lp;
        vplp.isDecor = true;
        return vplp;
    }

    /**
     * Store this information as the last requested Y coordinate for the given
     * tabIndex.
     *
     * @param index tabIndex The tab index being stored
     * @param y     The Y coordinate to move to
     */
    public void storeYCoordinate(int index, float y) {
        Coordinate coord = mCoordinates.get(index);
        if (coord == null) {
            coord = new Coordinate();
        }
        coord.y = y;
        mCoordinates.put(index, coord);
    }

    /**
     * Restore the Y position of this view to the last manually requested value.
     * This can be done after the parent has been re-laid out again, where this
     * view's position could have been lost if the view laid outside its
     * parent's bounds.
     *
     * @param duration The duration of the animation
     * @param tabIndex The index to restore
     */
    public void restoreYCoordinate(int duration, int tabIndex) {
        final float storedYCoordinate = getStoredYCoordinateForTab(tabIndex);
        if (getTranslationY() == storedYCoordinate || mIsAnimating)
            return;
        if (duration == 0) {
            setTranslationY(storedYCoordinate);
            invalidate();
            return;
        }

        mIsAnimating = true;
        final Interpolator interpolator = AnimationUtils.loadInterpolator(getContext(),
                android.R.anim.accelerate_decelerate_interpolator);

        final ObjectAnimator animator = ObjectAnimator.ofFloat(this, "translationY", storedYCoordinate);
        animator.setInterpolator(interpolator);
        animator.setDuration(duration);
        animator.start();
        animator.addUpdateListener(mAnimatorListener);
        animator.addListener(mAnimatorListener);
    }

    /**
     * Request that the view move to the given Y coordinate. Also store the Y
     * coordinate as the last requested Y coordinate for the given tabIndex.
     *
     * @param tabIndex The tab index being stored
     * @param y        The Y cooridinate to move to
     */
    public void moveToYCoordinate(int tabIndex, float y) {
        storeYCoordinate(tabIndex, y);
        if (mBlurBackground && mViewBackground instanceof BlurDrawable)
            ((BlurDrawable) mViewBackground).blur(Math.abs(y / getAllowedVerticalScrollLength()));
        restoreYCoordinate(0, tabIndex);
    }

    /**
     * Returns the stored Y coordinate of this view the last time the user was
     * on the selected tab given by tabIndex.
     *
     * @param tabIndex The tab index use to return the Y value
     */
    public float getStoredYCoordinateForTab(int tabIndex) {
        Coordinate coord = mCoordinates.get(tabIndex);
        if (coord == null) {
            coord = new Coordinate();
            mCoordinates.put(tabIndex, coord);
        }
        return coord.y;
    }

    /**
     * Returns the number of pixels that this view can be scrolled vertically
     * while still allowing the tab labels to still show
     */
    public int getAllowedVerticalScrollLength() {
        if (mMinHeight == Integer.MIN_VALUE)
            return getMeasuredHeight() - tabStripHeight;
        else
            return getMeasuredHeight() - mMinHeight;
    }

    public PageScrollHelper getPageScrollHelper() {
        return mPageScrollHelper;
    }

    private class GlobalLayoutListener implements OnGlobalLayoutListener {
        @SuppressWarnings("deprecation")
        @SuppressLint("NewApi")
        @Override
        public void onGlobalLayout() {

            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
                getViewTreeObserver().removeGlobalOnLayoutListener(this);
            } else {
                getViewTreeObserver().removeOnGlobalLayoutListener(this);
            }

            currentPosition = pager.getCurrentItem();
            scrollToChild(currentPosition, 0);
        }
    }

    private class AnimatorListener implements Animator.AnimatorListener, ValueAnimator.AnimatorUpdateListener {
        @Override
        public void onAnimationStart(Animator animation) {

        }

        @Override
        public void onAnimationEnd(Animator animation) {
            mIsAnimating = false;
        }

        @Override
        public void onAnimationCancel(Animator animation) {

        }

        @Override
        public void onAnimationRepeat(Animator animation) {

        }

        @Override
        public void onAnimationUpdate(ValueAnimator animation) {
            invalidate();
        }
    }

    private static class SavedState extends BaseSavedState {
        int currentPosition;

        public SavedState(Parcelable superState) {
            super(superState);
        }

        private SavedState(Parcel in) {
            super(in);
            currentPosition = in.readInt();
        }

        @Override
        public void writeToParcel(Parcel dest, int flags) {
            super.writeToParcel(dest, flags);
            dest.writeInt(currentPosition);
        }

        public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() {
            @Override
            public SavedState createFromParcel(Parcel in) {
                return new SavedState(in);
            }

            @Override
            public SavedState[] newArray(int size) {
                return new SavedState[size];
            }
        };
    }

    private class PageListener implements PageScrollListener {
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            currentPosition = position;
            currentPositionOffset = positionOffset;

            scrollToChild(position, (int) (positionOffset * tabsContainer.getChildAt(position).getWidth()));

            invalidate();

            if (mDelegatePageListener != null) {
                mDelegatePageListener.onPageScrolled(position, positionOffset, positionOffsetPixels);
            }
        }

        @Override
        public void onPageScrollStateChanged(int state) {
            if (state == ViewPager.SCROLL_STATE_IDLE) {
                Coordinate coord = mCoordinates.get(pager.getCurrentItem());
                if (coord != null && pager.findViewWithTag(coord) == null) {
                    mCoordinates.remove(pager.getCurrentItem());
                }
                restoreYCoordinate(75, pager.getCurrentItem());
                scrollToChild(pager.getCurrentItem(), 0);
            }

            if (mDelegatePageListener != null) {
                mDelegatePageListener.onPageScrollStateChanged(state);
            }
        }

        @Override
        public void onPageSelected(int position) {
            if (mDelegatePageListener != null) {
                mDelegatePageListener.onPageSelected(position);
            }
        }

        @Override
        public void onPageVerticalScroll(View v, int currentPage, int offset) {
            final float amtToScroll = Math.max(offset, -getAllowedVerticalScrollLength());
            moveToYCoordinate(currentPage, amtToScroll);
            v.setTag(mCoordinates.get(currentPage));
        }

        @Override
        public void onScrollStateChanged(int currentPage, int scrollState) {
        }
    }

    @Override
    public void setBackgroundColor(int color) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)
            super.setBackground(new ColorDrawable(color));
        else
            super.setBackgroundDrawable(new ColorDrawable(color));
    }

    @Override
    public void setBackground(Drawable background) {
        mViewBackground = background;
        setupBackground();
    }

    @Override
    public void setBackgroundDrawable(Drawable background) {
        mViewBackground = background;
        setupBackground();
    }

    @Override
    public void setBackgroundResource(int resid) {
        mViewBackground = getResources().getDrawable(resid);
        setupBackground();
    }

    public void setBackground(Bitmap bitmap) {
        BitmapDrawable drawable = new BitmapDrawable(getResources(), bitmap);
        setBackground(drawable);
    }

    private void setupBackground() {
        if (mBlurBackground && mViewBackground instanceof BitmapDrawable) {
            mViewBackground = new BlurDrawable(((BitmapDrawable) mViewBackground).getBitmap(), getContext());
        }

        if (mKenBurnsEffect
                && (mViewBackground instanceof BitmapDrawable || mViewBackground instanceof LayerDrawable)) {
            mViewBackground = new KenBurnsDrawable(mViewBackground);
            mViewBackground.setCallback(this);
        }
    }

    public void setIcon(Bitmap bitmap) {
        BitmapDrawable drawable = new BitmapDrawable(getResources(), bitmap);
        setIcon(drawable);
    }

    public void setIcon(Drawable drawable) {
        mIcon = drawable;
        setupIcon();
        invalidate();
    }

    public void setIcon(int resId) {
        Drawable drawable = getResources().getDrawable(resId);
        setIcon(drawable);
    }

    private void setupIcon() {
        if (!(mIcon instanceof BitmapDrawable))
            return;

        mIcon = new CircleFramedDrawable(((BitmapDrawable) mIcon).getBitmap(), mIconSize, mFrameColor, mStrokeWidth,
                mFrameShadowColor, mShadowRadius, mHighlightColor);
        mIcon.setBounds(0, 0, mIconSize, mIconSize);
    }
}