content: /*
   * 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 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;
  
  import com.cjj.bb.R;
  
  /**
   * 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];
              }
          };
      }
  }