//定義兩個變量，這個兩個變量是表示滑動時候，positionOffset 是從大到 //小的變化，還是從小到大的變化。用于在滑動時候，避免多次調用一個方法 private boolean isSmallToBig = true; private boolean isBigToSmall = false;  //記錄上一次滑動的positionOffsetPixels值  private int lastValue = -1;  @Override  public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {    if (positionOffset != 0) {      mCurrentPage = position;      boolean isLeft = true;      if (lastValue >= positionOffsetPixels) {        //右滑        isLeft = false;      } else if (lastValue < positionOffsetPixels) {        //左滑        isLeft = true;      }      setIndiactorView(positionOffset,isLeft);    }    lastValue = positionOffsetPixels;  }  private void setIndiactorView(float positionOffset,boolean isLeft) {        //設定滑動的邊界，這里設置的滑動到一半    float radiusOffsetHead = 0.5f;    //如果滑動小于一半，通過isSmallToBig這個變量來避免多次調用    // initIndicatorView 方法    if (positionOffset <= radiusOffsetHead && !isSmallToBig) {      initIndicatorView(mCurrentPage);      isSmallToBig = true;      isBigToSmall = false;    } else if (positionOffset > radiusOffsetHead && !isBigToSmall) {     //超過一半。如果是左滑，就-1，如果是右滑，就+1      int currnt = isLeft ? mCurrentPage + 1 : mCurrentPage - 1;      initIndicatorView(currnt);      isBigToSmall = true;      isSmallToBig = false;    }  }