使用自定义的LineHeightSpan替代lineSpacing小于1时的LineSpacingSpan。

示例代码如下：

class CustomLineHeightSpan(private val height: Int) : LineHeightSpan {

    override fun chooseHeight(
        text: CharSequence?,
        start: Int,
        end: Int,
        spanstartv: Int,
        v: Int,
        fm: Paint.FontMetricsInt?
    ) {
        if (fm != null) {
            val lineHeight = fm.bottom - fm.top
            if (lineHeight < height) {
                val delta = (height - lineHeight) / 2
                fm.top -= delta
                fm.ascent -= delta
                fm.bottom += delta
                fm.descent += delta
            }
        }
    }
}

// 可以在代码中设置TextView的行高
textView.setLineSpacing(0f, 1.5f)

// 在设置 SpannableString 时使用自定义的 LineHeightSpan
val spannableString = SpannableString("This is a text with background color")
val backgroundColorSpan = BackgroundColorSpan(Color.RED)
val lineHeightSpan =
    CustomLineHeightSpan((textView.textSize * (1 + 1.5f)).toInt())
spannableString.setSpan(
    backgroundColorSpan,
    5,
    10,
    Spanned.SPAN_INCLUSIVE_EXCLUSIVE
)
spannableString.setSpan(
    lineHeightSpan,
    5,
    10,
    Spanned.SPAN_INCLUSIVE_EXCLUSIVE
)