bottomView.frame = CGRectMake(bottomView.frame.origin.x, self.contentView.frame.size.height - keyboardHeight - kContentSize.height - textViewBgAndCursor*2, bottomView.frame.size.width, kContentSize.height + textViewBgAndCursor * 2);
所有的相关属性 都不是自己调用自己,因此,不会出现 a - 3 - 5,