Subversion Repositories SmartDukaan

/*

 * Copyright (C) 2012 Jake Wharton

 *

 * 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.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;

/**

 * Draws a line for each page. The current page line is colored differently

 * than the unselected page lines.

 */

public class UnderlinePageIndicator extends View implements PageIndicator {

    private static final int INVALID_POINTER = -1;

    private static final int FADE_FRAME_MS = 30;

    private final Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

    private boolean mFades;

    private int mFadeDelay;

    private int mFadeLength;

    private int mFadeBy;

    private ViewPager mViewPager;

    private ViewPager.OnPageChangeListener mListener;

    private int mScrollState;

    private int mCurrentPage;

    private float mPositionOffset;

    private int mTouchSlop;

    private float mLastMotionX = -1;

    private int mActivePointerId = INVALID_POINTER;

    private boolean mIsDragging;

    private final Runnable mFadeRunnable = new Runnable() {

      @Override public void run() {

        if (!mFades) return;

        final int alpha = Math.max(mPaint.getAlpha() - mFadeBy, 0);

        mPaint.setAlpha(alpha);

        invalidate();

        if (alpha > 0) {

          postDelayed(this, FADE_FRAME_MS);

        }

      }

    };

    public UnderlinePageIndicator(Context context) {

        this(context, null);

    }

    public UnderlinePageIndicator(Context context, AttributeSet attrs) {

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

    }

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

        super(context, attrs, defStyle);

        if (isInEditMode()) return;

        final Resources res = getResources();

        //Load defaults from resources

        final boolean defaultFades = res.getBoolean(R.bool.default_underline_indicator_fades);

        final int defaultFadeDelay = res.getInteger(R.integer.default_underline_indicator_fade_delay);

        final int defaultFadeLength = res.getInteger(R.integer.default_underline_indicator_fade_length);

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

        //Retrieve styles attributes

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

        setFades(a.getBoolean(R.styleable.UnderlinePageIndicator_fades, defaultFades));

        setSelectedColor(a.getColor(R.styleable.UnderlinePageIndicator_selectedColor, defaultSelectedColor));

        setFadeDelay(a.getInteger(R.styleable.UnderlinePageIndicator_fadeDelay, defaultFadeDelay));

        setFadeLength(a.getInteger(R.styleable.UnderlinePageIndicator_fadeLength, defaultFadeLength));

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

        if (background != null) {

          setBackgroundDrawable(background);

        }

        a.recycle();

        final ViewConfiguration configuration = ViewConfiguration.get(context);

        mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration);

    }

    public boolean getFades() {

        return mFades;

    }

    public void setFades(boolean fades) {

        if (fades != mFades) {

            mFades = fades;

            if (fades) {

                post(mFadeRunnable);

            } else {

                removeCallbacks(mFadeRunnable);

                mPaint.setAlpha(0xFF);

                invalidate();

            }

        }

    }

    public int getFadeDelay() {

        return mFadeDelay;

    }

    public void setFadeDelay(int fadeDelay) {

        mFadeDelay = fadeDelay;

    }

    public int getFadeLength() {

        return mFadeLength;

    }

    public void setFadeLength(int fadeLength) {

        mFadeLength = fadeLength;

        mFadeBy = 0xFF / (mFadeLength / FADE_FRAME_MS);

    }

    public int getSelectedColor() {

        return mPaint.getColor();

    }

    public void setSelectedColor(int selectedColor) {

        mPaint.setColor(selectedColor);

        invalidate();

    }

    @Override

    protected void onDraw(Canvas canvas) {

        super.onDraw(canvas);

        if (mViewPager == null) {

            return;

        }

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

        if (count == 0) {

            return;

        }

        if (mCurrentPage >= count) {

            setCurrentItem(count - 1);

            return;

        }

        final int paddingLeft = getPaddingLeft();

        final float pageWidth = (getWidth() - paddingLeft - getPaddingRight()) / (1f * count);

        final float left = paddingLeft + pageWidth * (mCurrentPage + mPositionOffset);

        final float right = left + pageWidth;

        final float top = getPaddingTop();

        final float bottom = getHeight() - getPaddingBottom();

        canvas.drawRect(left, top, right, bottom, mPaint);

    }

    public boolean onTouchEvent(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;

                    if ((mCurrentPage > 0) && (ev.getX() < halfWidth - sixthWidth)) {

                        if (action != MotionEvent.ACTION_CANCEL) {

                            mViewPager.setCurrentItem(mCurrentPage - 1);

                        }

                        return true;

                    } else if ((mCurrentPage < count - 1) && (ev.getX() > halfWidth + sixthWidth)) {

                        if (action != MotionEvent.ACTION_CANCEL) {

                            mViewPager.setCurrentItem(mCurrentPage + 1);

                        }

                        return true;

                    }

                }

                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;

    }

    @Override

    public void setViewPager(ViewPager viewPager) {

        if (mViewPager == viewPager) {

            return;

        }

        if (mViewPager != null) {

            //Clear us from the old pager.

            mViewPager.setOnPageChangeListener(null);

        }

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

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

        }

        mViewPager = viewPager;

        mViewPager.setOnPageChangeListener(this);

        invalidate();

        post(new Runnable() {

            @Override public void run() {

                if (mFades) {

                    post(mFadeRunnable);

                }

            }

        });

    }

    @Override

    public void setViewPager(ViewPager view, int initialPosition) {

        setViewPager(view);

        setCurrentItem(initialPosition);

    }

    @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 notifyDataSetChanged() {

        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;

        mPositionOffset = positionOffset;

        if (mFades) {

            if (positionOffsetPixels > 0) {

                removeCallbacks(mFadeRunnable);

                mPaint.setAlpha(0xFF);

            } else if (mScrollState != ViewPager.SCROLL_STATE_DRAGGING) {

                postDelayed(mFadeRunnable, mFadeDelay);

            }

        }

        invalidate();

        if (mListener != null) {

            mListener.onPageScrolled(position, positionOffset, positionOffsetPixels);

        }

    }

    @Override

    public void onPageSelected(int position) {

        if (mScrollState == ViewPager.SCROLL_STATE_IDLE) {

            mCurrentPage = position;

            mPositionOffset = 0;

            invalidate();

            mFadeRunnable.run();

        }

        if (mListener != null) {

            mListener.onPageSelected(position);

        }

    }

    @Override

    public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) {

        mListener = listener;

    }

    @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 Creator<SavedState> CREATOR = new Creator<SavedState>() {

            @Override

            public SavedState createFromParcel(Parcel in) {

                return new SavedState(in);

            }

            @Override

            public SavedState[] newArray(int size) {

                return new SavedState[size];

            }

        };

    }

}