Subversion Repositories SmartDukaan

/*

 * Copyright (C) 2011 Jake Wharton

 * Copyright (C) 2011 Patrik Akerfeldt

 * Copyright (C) 2011 Francisco Figueiredo Jr.

 *

 * 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 com.viewpagerindicator;

import android.content.Context;

import android.content.res.Resources;

import android.content.res.TypedArray;

import android.graphics.Canvas;

import android.graphics.Paint;

import android.graphics.Path;

import android.graphics.Rect;

import android.graphics.Typeface;

import android.graphics.drawable.Drawable;

import android.os.Parcel;

import android.os.Parcelable;

import android.support.v4.view.MotionEventCompat;

import android.support.v4.view.ViewConfigurationCompat;

import android.support.v4.view.ViewPager;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.View;

import android.view.ViewConfiguration;

import java.util.ArrayList;

/**

 * A TitlePageIndicator is a PageIndicator which displays the title of left view

 * (if exist), the title of the current select view (centered) and the title of

 * the right view (if exist). When the user scrolls the ViewPager then titles are

 * also scrolled.

 */

public class TitlePageIndicator extends View implements PageIndicator {

    /**

     * Percentage indicating what percentage of the screen width away from

     * center should the underline be fully faded. A value of 0.25 means that

     * halfway between the center of the screen and an edge.

     */

    private static final float SELECTION_FADE_PERCENTAGE = 0.25f;

    /**

     * Percentage indicating what percentage of the screen width away from

     * center should the selected text bold turn off. A value of 0.05 means

     * that 10% between the center and an edge.

     */

    private static final float BOLD_FADE_PERCENTAGE = 0.05f;

    /**

     * Title text used when no title is provided by the adapter.

     */

    private static final String EMPTY_TITLE = "";

    /**

     * Interface for a callback when the center item has been clicked.

     */

    public interface OnCenterItemClickListener {

        /**

         * Callback when the center item has been clicked.

         *

         * @param position Position of the current center item.

         */

        void onCenterItemClick(int position);

    }

    public enum IndicatorStyle {

        None(0), Triangle(1), Underline(2);

        public final int value;

        private IndicatorStyle(int value) {

            this.value = value;

        }

        public static IndicatorStyle fromValue(int value) {

            for (IndicatorStyle style : IndicatorStyle.values()) {

                if (style.value == value) {

                    return style;

                }

            }

            return null;

        }

    }

    public enum LinePosition {

        Bottom(0), Top(1);

        public final int value;

        private LinePosition(int value) {

            this.value = value;

        }

        public static LinePosition fromValue(int value) {

            for (LinePosition position : LinePosition.values()) {

                if (position.value == value) {

                    return position;

                }

            }

            return null;

        }

    }

    private ViewPager mViewPager;

    private ViewPager.OnPageChangeListener mListener;

    private int mCurrentPage = -1;

    private float mPageOffset;

    private int mScrollState;

    private final Paint mPaintText = new Paint();

    private boolean mBoldText;

    private int mColorText;

    private int mColorSelected;

    private Path mPath = new Path();

    private final Rect mBounds = new Rect();

    private final Paint mPaintFooterLine = new Paint();

    private IndicatorStyle mFooterIndicatorStyle;

    private LinePosition mLinePosition;

    private final Paint mPaintFooterIndicator = new Paint();

    private float mFooterIndicatorHeight;

    private float mFooterIndicatorUnderlinePadding;

    private float mFooterPadding;

    private float mTitlePadding;

    private float mTopPadding;

    /** Left and right side padding for not active view titles. */

    private float mClipPadding;

    private float mFooterLineHeight;

    private static final int INVALID_POINTER = -1;

    private int mTouchSlop;

    private float mLastMotionX = -1;

    private int mActivePointerId = INVALID_POINTER;

    private boolean mIsDragging;

    private OnCenterItemClickListener mCenterItemClickListener;

    public TitlePageIndicator(Context context) {

        this(context, null);

    }

    public TitlePageIndicator(Context context, AttributeSet attrs) {

        this(context, attrs, R.attr.vpiTitlePageIndicatorStyle);

    }

    public TitlePageIndicator(Context context, AttributeSet attrs, int defStyle) {

        super(context, attrs, defStyle);

        if (isInEditMode()) return;

        //Load defaults from resources

        final Resources res = getResources();

        final int defaultFooterColor = res.getColor(R.color.default_title_indicator_footer_color);

        final float defaultFooterLineHeight = res.getDimension(R.dimen.default_title_indicator_footer_line_height);

        final int defaultFooterIndicatorStyle = res.getInteger(R.integer.default_title_indicator_footer_indicator_style);

        final float defaultFooterIndicatorHeight = res.getDimension(R.dimen.default_title_indicator_footer_indicator_height);

        final float defaultFooterIndicatorUnderlinePadding = res.getDimension(R.dimen.default_title_indicator_footer_indicator_underline_padding);

        final float defaultFooterPadding = res.getDimension(R.dimen.default_title_indicator_footer_padding);

        final int defaultLinePosition = res.getInteger(R.integer.default_title_indicator_line_position);

        final int defaultSelectedColor = res.getColor(R.color.default_title_indicator_selected_color);

        final boolean defaultSelectedBold = res.getBoolean(R.bool.default_title_indicator_selected_bold);

        final int defaultTextColor = res.getColor(R.color.default_title_indicator_text_color);

        final float defaultTextSize = res.getDimension(R.dimen.default_title_indicator_text_size);

        final float defaultTitlePadding = res.getDimension(R.dimen.default_title_indicator_title_padding);

        final float defaultClipPadding = res.getDimension(R.dimen.default_title_indicator_clip_padding);

        final float defaultTopPadding = res.getDimension(R.dimen.default_title_indicator_top_padding);

        //Retrieve styles attributes

        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.TitlePageIndicator, defStyle, 0);

        //Retrieve the colors to be used for this view and apply them.

        mFooterLineHeight = a.getDimension(R.styleable.TitlePageIndicator_footerLineHeight, defaultFooterLineHeight);

        mFooterIndicatorStyle = IndicatorStyle.fromValue(a.getInteger(R.styleable.TitlePageIndicator_footerIndicatorStyle, defaultFooterIndicatorStyle));

        mFooterIndicatorHeight = a.getDimension(R.styleable.TitlePageIndicator_footerIndicatorHeight, defaultFooterIndicatorHeight);

        mFooterIndicatorUnderlinePadding = a.getDimension(R.styleable.TitlePageIndicator_footerIndicatorUnderlinePadding, defaultFooterIndicatorUnderlinePadding);

        mFooterPadding = a.getDimension(R.styleable.TitlePageIndicator_footerPadding, defaultFooterPadding);

        mLinePosition = LinePosition.fromValue(a.getInteger(R.styleable.TitlePageIndicator_linePosition, defaultLinePosition));

        mTopPadding = a.getDimension(R.styleable.TitlePageIndicator_topPadding, defaultTopPadding);

        mTitlePadding = a.getDimension(R.styleable.TitlePageIndicator_titlePadding, defaultTitlePadding);

        mClipPadding = a.getDimension(R.styleable.TitlePageIndicator_clipPadding, defaultClipPadding);

        mColorSelected = a.getColor(R.styleable.TitlePageIndicator_selectedColor, defaultSelectedColor);

        mColorText = a.getColor(R.styleable.TitlePageIndicator_android_textColor, defaultTextColor);

        mBoldText = a.getBoolean(R.styleable.TitlePageIndicator_selectedBold, defaultSelectedBold);

        final float textSize = a.getDimension(R.styleable.TitlePageIndicator_android_textSize, defaultTextSize);

        final int footerColor = a.getColor(R.styleable.TitlePageIndicator_footerColor, defaultFooterColor);

        mPaintText.setTextSize(textSize);

        mPaintText.setAntiAlias(true);

        mPaintFooterLine.setStyle(Paint.Style.FILL_AND_STROKE);

        mPaintFooterLine.setStrokeWidth(mFooterLineHeight);

        mPaintFooterLine.setColor(footerColor);

        mPaintFooterIndicator.setStyle(Paint.Style.FILL_AND_STROKE);

        mPaintFooterIndicator.setColor(footerColor);

        Drawable background = a.getDrawable(R.styleable.TitlePageIndicator_android_background);

        if (background != null) {

          setBackgroundDrawable(background);

        }

        a.recycle();

        final ViewConfiguration configuration = ViewConfiguration.get(context);

        mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration);

    }

    public int getFooterColor() {

        return mPaintFooterLine.getColor();

    }

    public void setFooterColor(int footerColor) {

        mPaintFooterLine.setColor(footerColor);

        mPaintFooterIndicator.setColor(footerColor);

        invalidate();

    }

    public float getFooterLineHeight() {

        return mFooterLineHeight;

    }

    public void setFooterLineHeight(float footerLineHeight) {

        mFooterLineHeight = footerLineHeight;

        mPaintFooterLine.setStrokeWidth(mFooterLineHeight);

        invalidate();

    }

    public float getFooterIndicatorHeight() {

        return mFooterIndicatorHeight;

    }

    public void setFooterIndicatorHeight(float footerTriangleHeight) {

        mFooterIndicatorHeight = footerTriangleHeight;

        invalidate();

    }

    public float getFooterIndicatorPadding() {

        return mFooterPadding;

    }

    public void setFooterIndicatorPadding(float footerIndicatorPadding) {

        mFooterPadding = footerIndicatorPadding;

        invalidate();

    }

    public IndicatorStyle getFooterIndicatorStyle() {

        return mFooterIndicatorStyle;

    }

    public void setFooterIndicatorStyle(IndicatorStyle indicatorStyle) {

        mFooterIndicatorStyle = indicatorStyle;

        invalidate();

    }

    public LinePosition getLinePosition() {

        return mLinePosition;

    }

    public void setLinePosition(LinePosition linePosition) {

        mLinePosition = linePosition;

        invalidate();

    }

    public int getSelectedColor() {

        return mColorSelected;

    }

    public void setSelectedColor(int selectedColor) {

        mColorSelected = selectedColor;

        invalidate();

    }

    public boolean isSelectedBold() {

        return mBoldText;

    }

    public void setSelectedBold(boolean selectedBold) {

        mBoldText = selectedBold;

        invalidate();

    }

    public int getTextColor() {

        return mColorText;

    }

    public void setTextColor(int textColor) {

        mPaintText.setColor(textColor);

        mColorText = textColor;

        invalidate();

    }

    public float getTextSize() {

        return mPaintText.getTextSize();

    }

    public void setTextSize(float textSize) {

        mPaintText.setTextSize(textSize);

        invalidate();

    }

    public float getTitlePadding() {

        return this.mTitlePadding;

    }

    public void setTitlePadding(float titlePadding) {

        mTitlePadding = titlePadding;

        invalidate();

    }

    public float getTopPadding() {

        return this.mTopPadding;

    }

    public void setTopPadding(float topPadding) {

        mTopPadding = topPadding;

        invalidate();

    }

    public float getClipPadding() {

        return this.mClipPadding;

    }

    public void setClipPadding(float clipPadding) {

        mClipPadding = clipPadding;

        invalidate();

    }

    public void setTypeface(Typeface typeface) {

        mPaintText.setTypeface(typeface);

        invalidate();

    }

    public Typeface getTypeface() {

        return mPaintText.getTypeface();

    }

    /*

     * (non-Javadoc)

     *

     * @see android.view.View#onDraw(android.graphics.Canvas)

     */

    @Override

    protected void onDraw(Canvas canvas) {

        super.onDraw(canvas);

        if (mViewPager == null) {

            return;

        }

        final int count = mViewPager.getAdapter().getCount();

        if (count == 0) {

            return;

        }

        // mCurrentPage is -1 on first start and after orientation changed. If so, retrieve the correct index from viewpager.

        if (mCurrentPage == -1 && mViewPager != null) {

            mCurrentPage = mViewPager.getCurrentItem();

        }

        //Calculate views bounds

        ArrayList<Rect> bounds = calculateAllBounds(mPaintText);

        final int boundsSize = bounds.size();

        //Make sure we're on a page that still exists

        if (mCurrentPage >= boundsSize) {

            setCurrentItem(boundsSize - 1);

            return;

        }

        final int countMinusOne = count - 1;

        final float halfWidth = getWidth() / 2f;

        final int left = getLeft();

        final float leftClip = left + mClipPadding;

        final int width = getWidth();

        int height = getHeight();

        final int right = left + width;

        final float rightClip = right - mClipPadding;

        int page = mCurrentPage;

        float offsetPercent;

        if (mPageOffset <= 0.5) {

            offsetPercent = mPageOffset;

        } else {

            page += 1;

            offsetPercent = 1 - mPageOffset;

        }

        final boolean currentSelected = (offsetPercent <= SELECTION_FADE_PERCENTAGE);

        final boolean currentBold = (offsetPercent <= BOLD_FADE_PERCENTAGE);

        final float selectedPercent = (SELECTION_FADE_PERCENTAGE - offsetPercent) / SELECTION_FADE_PERCENTAGE;

        //Verify if the current view must be clipped to the screen

        Rect curPageBound = bounds.get(mCurrentPage);

        float curPageWidth = curPageBound.right - curPageBound.left;

        if (curPageBound.left < leftClip) {

            //Try to clip to the screen (left side)

            clipViewOnTheLeft(curPageBound, curPageWidth, left);

        }

        if (curPageBound.right > rightClip) {

            //Try to clip to the screen (right side)

            clipViewOnTheRight(curPageBound, curPageWidth, right);

        }

        //Left views starting from the current position

        if (mCurrentPage > 0) {

            for (int i = mCurrentPage - 1; i >= 0; i--) {

                Rect bound = bounds.get(i);

                //Is left side is outside the screen

                if (bound.left < leftClip) {

                    int w = bound.right - bound.left;

                    //Try to clip to the screen (left side)

                    clipViewOnTheLeft(bound, w, left);

                    //Except if there's an intersection with the right view

                    Rect rightBound = bounds.get(i + 1);

                    //Intersection

                    if (bound.right + mTitlePadding > rightBound.left) {

                        bound.left = (int) (rightBound.left - w - mTitlePadding);

                        bound.right = bound.left + w;

                    }

                }

            }

        }

        //Right views starting from the current position

        if (mCurrentPage < countMinusOne) {

            for (int i = mCurrentPage + 1 ; i < count; i++) {

                Rect bound = bounds.get(i);

                //If right side is outside the screen

                if (bound.right > rightClip) {

                    int w = bound.right - bound.left;

                    //Try to clip to the screen (right side)

                    clipViewOnTheRight(bound, w, right);

                    //Except if there's an intersection with the left view

                    Rect leftBound = bounds.get(i - 1);

                    //Intersection

                    if (bound.left - mTitlePadding < leftBound.right) {

                        bound.left = (int) (leftBound.right + mTitlePadding);

                        bound.right = bound.left + w;

                    }

                }

            }

        }

        //Now draw views

        int colorTextAlpha = mColorText >>> 24;

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

            //Get the title

            Rect bound = bounds.get(i);

            //Only if one side is visible

            if ((bound.left > left && bound.left < right) || (bound.right > left && bound.right < right)) {

                final boolean currentPage = (i == page);

                final CharSequence pageTitle = getTitle(i);

                //Only set bold if we are within bounds

                mPaintText.setFakeBoldText(currentPage && currentBold && mBoldText);

                //Draw text as unselected

                mPaintText.setColor(mColorText);

                if(currentPage && currentSelected) {

                    //Fade out/in unselected text as the selected text fades in/out

                    mPaintText.setAlpha(colorTextAlpha - (int)(colorTextAlpha * selectedPercent));

                }

                //Except if there's an intersection with the right view

                if (i < boundsSize - 1)  {

                    Rect rightBound = bounds.get(i + 1);

                    //Intersection

                    if (bound.right + mTitlePadding > rightBound.left) {

                        int w = bound.right - bound.left;

                        bound.left = (int) (rightBound.left - w - mTitlePadding);

                        bound.right = bound.left + w;

                    }

                }

                canvas.drawText(pageTitle, 0, pageTitle.length(), bound.left, bound.bottom + mTopPadding, mPaintText);

                //If we are within the selected bounds draw the selected text

                if (currentPage && currentSelected) {

                    mPaintText.setColor(mColorSelected);

                    mPaintText.setAlpha((int)((mColorSelected >>> 24) * selectedPercent));

                    canvas.drawText(pageTitle, 0, pageTitle.length(), bound.left, bound.bottom + mTopPadding, mPaintText);

                }

            }

        }

        //If we want the line on the top change height to zero and invert the line height to trick the drawing code

        float footerLineHeight = mFooterLineHeight;

        float footerIndicatorLineHeight = mFooterIndicatorHeight;

        if (mLinePosition == LinePosition.Top) {

            height = 0;

            footerLineHeight = -footerLineHeight;

            footerIndicatorLineHeight = -footerIndicatorLineHeight;

        }

        //Draw the footer line

        mPath.reset();

        mPath.moveTo(0, height - footerLineHeight / 2f);

        mPath.lineTo(width, height - footerLineHeight / 2f);

        mPath.close();

        canvas.drawPath(mPath, mPaintFooterLine);

        float heightMinusLine = height - footerLineHeight;

        switch (mFooterIndicatorStyle) {

            case Triangle:

                mPath.reset();

                mPath.moveTo(halfWidth, heightMinusLine - footerIndicatorLineHeight);

                mPath.lineTo(halfWidth + footerIndicatorLineHeight, heightMinusLine);

                mPath.lineTo(halfWidth - footerIndicatorLineHeight, heightMinusLine);

                mPath.close();

                canvas.drawPath(mPath, mPaintFooterIndicator);

                break;

            case Underline:

                if (!currentSelected || page >= boundsSize) {

                    break;

                }

                Rect underlineBounds = bounds.get(page);

                final float rightPlusPadding = underlineBounds.right + mFooterIndicatorUnderlinePadding;

                final float leftMinusPadding = underlineBounds.left - mFooterIndicatorUnderlinePadding;

                final float heightMinusLineMinusIndicator = heightMinusLine - footerIndicatorLineHeight;

                mPath.reset();

                mPath.moveTo(leftMinusPadding, heightMinusLine);

                mPath.lineTo(rightPlusPadding, heightMinusLine);

                mPath.lineTo(rightPlusPadding, heightMinusLineMinusIndicator);

                mPath.lineTo(leftMinusPadding, heightMinusLineMinusIndicator);

                mPath.close();

                mPaintFooterIndicator.setAlpha((int)(0xFF * selectedPercent));

                canvas.drawPath(mPath, mPaintFooterIndicator);

                mPaintFooterIndicator.setAlpha(0xFF);

                break;

        }

    }

    public boolean onTouchEvent(android.view.MotionEvent ev) {

        if (super.onTouchEvent(ev)) {

            return true;

        }

        if ((mViewPager == null) || (mViewPager.getAdapter().getCount() == 0)) {

            return false;

        }

        final int action = ev.getAction() & MotionEventCompat.ACTION_MASK;

        switch (action) {

            case MotionEvent.ACTION_DOWN:

                mActivePointerId = MotionEventCompat.getPointerId(ev, 0);

                mLastMotionX = ev.getX();

                break;

            case MotionEvent.ACTION_MOVE: {

                final int activePointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);

                final float x = MotionEventCompat.getX(ev, activePointerIndex);

                final float deltaX = x - mLastMotionX;

                if (!mIsDragging) {

                    if (Math.abs(deltaX) > mTouchSlop) {

                        mIsDragging = true;

                    }

                }

                if (mIsDragging) {

                    mLastMotionX = x;

                    if (mViewPager.isFakeDragging() || mViewPager.beginFakeDrag()) {

                        mViewPager.fakeDragBy(deltaX);

                    }

                }

                break;

            }

            case MotionEvent.ACTION_CANCEL:

            case MotionEvent.ACTION_UP:

                if (!mIsDragging) {

                    final int count = mViewPager.getAdapter().getCount();

                    final int width = getWidth();

                    final float halfWidth = width / 2f;

                    final float sixthWidth = width / 6f;

                    final float leftThird = halfWidth - sixthWidth;

                    final float rightThird = halfWidth + sixthWidth;

                    final float eventX = ev.getX();

                    if (eventX < leftThird) {

                        if (mCurrentPage > 0) {

                            if (action != MotionEvent.ACTION_CANCEL) {

                                mViewPager.setCurrentItem(mCurrentPage - 1);

                            }

                            return true;

                        }

                    } else if (eventX > rightThird) {

                        if (mCurrentPage < count - 1) {

                            if (action != MotionEvent.ACTION_CANCEL) {

                                mViewPager.setCurrentItem(mCurrentPage + 1);

                            }

                            return true;

                        }

                    } else {

                        //Middle third

                        if (mCenterItemClickListener != null && action != MotionEvent.ACTION_CANCEL) {

                            mCenterItemClickListener.onCenterItemClick(mCurrentPage);

                        }

                    }

                }

                mIsDragging = false;

                mActivePointerId = INVALID_POINTER;

                if (mViewPager.isFakeDragging()) mViewPager.endFakeDrag();

                break;

            case MotionEventCompat.ACTION_POINTER_DOWN: {

                final int index = MotionEventCompat.getActionIndex(ev);

                mLastMotionX = MotionEventCompat.getX(ev, index);

                mActivePointerId = MotionEventCompat.getPointerId(ev, index);

                break;

            }

            case MotionEventCompat.ACTION_POINTER_UP:

                final int pointerIndex = MotionEventCompat.getActionIndex(ev);

                final int pointerId = MotionEventCompat.getPointerId(ev, pointerIndex);

                if (pointerId == mActivePointerId) {

                    final int newPointerIndex = pointerIndex == 0 ? 1 : 0;

                    mActivePointerId = MotionEventCompat.getPointerId(ev, newPointerIndex);

                }

                mLastMotionX = MotionEventCompat.getX(ev, MotionEventCompat.findPointerIndex(ev, mActivePointerId));

                break;

        }

        return true;

    }

    /**

     * Set bounds for the right textView including clip padding.

     *

     * @param curViewBound

     *            current bounds.

     * @param curViewWidth

     *            width of the view.

     */

    private void clipViewOnTheRight(Rect curViewBound, float curViewWidth, int right) {

        curViewBound.right = (int) (right - mClipPadding);

        curViewBound.left = (int) (curViewBound.right - curViewWidth);

    }

    /**

     * Set bounds for the left textView including clip padding.

     *

     * @param curViewBound

     *            current bounds.

     * @param curViewWidth

     *            width of the view.

     */

    private void clipViewOnTheLeft(Rect curViewBound, float curViewWidth, int left) {

        curViewBound.left = (int) (left + mClipPadding);

        curViewBound.right = (int) (mClipPadding + curViewWidth);

    }

    /**

     * Calculate views bounds and scroll them according to the current index

     *

     * @param paint

     * @return

     */

    private ArrayList<Rect> calculateAllBounds(Paint paint) {

        ArrayList<Rect> list = new ArrayList<Rect>();

        //For each views (If no values then add a fake one)

        final int count = mViewPager.getAdapter().getCount();

        final int width = getWidth();

        final int halfWidth = width / 2;

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

            Rect bounds = calcBounds(i, paint);

            int w = bounds.right - bounds.left;

            int h = bounds.bottom - bounds.top;

            bounds.left = (int)(halfWidth - (w / 2f) + ((i - mCurrentPage - mPageOffset) * width));

            bounds.right = bounds.left + w;

            bounds.top = 0;

            bounds.bottom = h;

            list.add(bounds);

        }

        return list;

    }

    /**

     * Calculate the bounds for a view's title

     *

     * @param index

     * @param paint

     * @return

     */

    private Rect calcBounds(int index, Paint paint) {

        //Calculate the text bounds

        Rect bounds = new Rect();

        CharSequence title = getTitle(index);

        bounds.right = (int) paint.measureText(title, 0, title.length());

        bounds.bottom = (int) (paint.descent() - paint.ascent());

        return bounds;

    }

    @Override

    public void setViewPager(ViewPager view) {

        if (mViewPager == view) {

            return;

        }

        if (mViewPager != null) {

            mViewPager.setOnPageChangeListener(null);

        }

        if (view.getAdapter() == null) {

            throw new IllegalStateException("ViewPager does not have adapter instance.");

        }

        mViewPager = view;

        mViewPager.setOnPageChangeListener(this);

        invalidate();

    }

    @Override

    public void setViewPager(ViewPager view, int initialPosition) {

        setViewPager(view);

        setCurrentItem(initialPosition);

    }

    @Override

    public void notifyDataSetChanged() {

        invalidate();

    }

    /**

     * Set a callback listener for the center item click.

     *

     * @param listener Callback instance.

     */

    public void setOnCenterItemClickListener(OnCenterItemClickListener listener) {

        mCenterItemClickListener = listener;

    }

    @Override

    public void setCurrentItem(int item) {

        if (mViewPager == null) {

            throw new IllegalStateException("ViewPager has not been bound.");

        }

        mViewPager.setCurrentItem(item);

        mCurrentPage = item;

        invalidate();

    }

    @Override

    public void onPageScrollStateChanged(int state) {

        mScrollState = state;

        if (mListener != null) {

            mListener.onPageScrollStateChanged(state);

        }

    }

    @Override

    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

        mCurrentPage = position;

        mPageOffset = positionOffset;

        invalidate();

        if (mListener != null) {

            mListener.onPageScrolled(position, positionOffset, positionOffsetPixels);

        }

    }

    @Override

    public void onPageSelected(int position) {

        if (mScrollState == ViewPager.SCROLL_STATE_IDLE) {

            mCurrentPage = position;

            invalidate();

        }

        if (mListener != null) {

            mListener.onPageSelected(position);

        }

    }

    @Override

    public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) {

        mListener = listener;

    }

    @Override

    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

        //Measure our width in whatever mode specified

        final int measuredWidth = MeasureSpec.getSize(widthMeasureSpec);

        //Determine our height

        float height;

        final int heightSpecMode = MeasureSpec.getMode(heightMeasureSpec);

        if (heightSpecMode == MeasureSpec.EXACTLY) {

            //We were told how big to be

            height = MeasureSpec.getSize(heightMeasureSpec);

        } else {

            //Calculate the text bounds

            mBounds.setEmpty();

            mBounds.bottom = (int) (mPaintText.descent() - mPaintText.ascent());

            height = mBounds.bottom - mBounds.top + mFooterLineHeight + mFooterPadding + mTopPadding;

            if (mFooterIndicatorStyle != IndicatorStyle.None) {

                height += mFooterIndicatorHeight;

            }

        }

        final int measuredHeight = (int)height;

        setMeasuredDimension(measuredWidth, measuredHeight);

    }

    @Override

    public void onRestoreInstanceState(Parcelable state) {

        SavedState savedState = (SavedState)state;

        super.onRestoreInstanceState(savedState.getSuperState());

        mCurrentPage = savedState.currentPage;

        requestLayout();

    }

    @Override

    public Parcelable onSaveInstanceState() {

        Parcelable superState = super.onSaveInstanceState();

        SavedState savedState = new SavedState(superState);

        savedState.currentPage = mCurrentPage;

        return savedState;

    }

    static class SavedState extends BaseSavedState {

        int currentPage;

        public SavedState(Parcelable superState) {

            super(superState);

        }

        private SavedState(Parcel in) {

            super(in);

            currentPage = in.readInt();

        }

        @Override

        public void writeToParcel(Parcel dest, int flags) {

            super.writeToParcel(dest, flags);

            dest.writeInt(currentPage);

        }

        @SuppressWarnings("UnusedDeclaration")

        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 CharSequence getTitle(int i) {

        CharSequence title = mViewPager.getAdapter().getPageTitle(i);

        if (title == null) {

            title = EMPTY_TITLE;

        }

        return title;

    }

}