public void setNonPrimaryAlpha(float alpha) {
    mNonPrimaryAlpha = (int) (alpha * 255) & 0xFF;
    final int transparentColor = (mNonPrimaryAlpha << 24) | (mTextColor & 0xFFFFFF);
    mPrevText.setTextColor(transparentColor);
    mNextText.setTextColor(transparentColor);
  }
Set the alpha value used for non-primary page titles.

@param alpha Opacity value in the range 0-1f
sample/src/main/java/android/support/v4/view/PagerTitleStripV22.java