Android Span富文本简单使用 - Spannable

###为文字实现很丰富的特殊效果，下面来实现几种很常用的操作

so... 直接上效果：

​先简单介绍下Spanable中的常用常量：

Spanned.SPAN_EXCLUSIVE_EXCLUSIVE -- 不包含start和end所在的端点              (a,b)

Spanned.SPAN_EXCLUSIVE_INCLUSIVE -- 不包含端start，但包含end所在的端点       (a,b]

Spanned.SPAN_INCLUSIVE_EXCLUSIVE -- 包含start，但不包含end所在的端点         [a,b)

Spanned.SPAN_INCLUSIVE_INCLUSIVE -- 包含start和end所在的端点                [a,b]

 

#1 设置部分文字的大小/颜色以及改变字体：

 ##改变大小：AbsoluteSizeSpan/RelativeSizeSpan

//设置部分文字的大小 AbsoluteSizeSpan/RelativeSizeSpan
sb.setSpan(
            AbsoluteSizeSpan(size),
            index,
            index + TEXT_SUB.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )

 ##改变大小：ForegroundColorSpan

//改变部分文字的颜色
sb.setSpan(
            ForegroundColorSpan(color),
            index,
            index + TEXT_SUB.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )

 ##除了上面的简单的两种，我们还可以用：TextAppearanceSpan

//更改Text的一些属性
sb.setSpan(
            TextAppearanceSpan(this, R.style.DateTextOther),
            index,
            index + TEXT_SUB.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )

 cc：使用TextAppearanceSpan，可以直接同时更改Text的各种属性，再贴上简单的style： R.style.DateTextOther

<style name="DateTextOther">
        <item name="android:textSize">12sp</item>
        <item name="android:textColor">@color/colorAccent</item>
        <item name="android:textAllCaps">true</item>
        <item name="android:typeface">serif</item>
        <item name="android:fontFamily">@font/graphik_bold</item>
    </style>

 

#2 设置部分文字的背景色：BackgroundColorSpan

//设置部分文字背景色
sb.setSpan(
            BackgroundColorSpan(color),
            index,
            index + TEXT_SUB.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )

 

#3 设置部分文字的下划线/删除线：UnderlineSpan/StrikethroughSpan

//设置部分文字添加下划线
sb.setSpan(
            UnderlineSpan(),
            index,
            index + TEXT_SUB.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )

 

#4 设置部分文字的上下标：SuperscriptSpan/SubscriptSpan

//设置为上标
sb.setSpan(
            SuperscriptSpan(),
            indexTH,
            indexTH + TEXT_TH.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )

//设置为下标
sb.setSpan(
            SubscriptSpan(),
            index,
            index + TEXT_SUB.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )

 

##最后贴上Activity示例：

class TextSpanActivity : AppCompatActivity() {

    companion object {
        private const val TEXT_CONTENT = "Today is Jul 25th"
        private const val TEXT_SUB = "Jul"
        private const val TEXT_TH = "th"
    }

    private val index by lazy { TEXT_CONTENT.indexOf(TEXT_SUB) }
    private val indexTH by lazy { TEXT_CONTENT.indexOf(TEXT_TH) }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_text_span)
        initView()
    }

    private fun initView() {
        text_type_size.text = getAbsoluteSizeSpan(12.toDp())
        text_type_color.text = getTextForegroundColorSpan(resources.getColor(R.color.colorAccent))
        text_type_text.text = getTextAppearanceSpan(R.style.DateTextOther)
        text_type_background.text = getBackgroundColorSpan(resources.getColor(R.color.colorAccent))
        text_type_underline.text = getUnderlineSpan()
        text_type_strikethrough.text = getStrikethroughSpan()
        text_type_superscript.text = getSuperscript_SubscriptSpan()
    }

    //设置部分文字的大小 AbsoluteSizeSpan/RelativeSizeSpan
    private fun getAbsoluteSizeSpan(size: Int): Spannable {
        val sb = SpannableStringBuilder(TEXT_CONTENT)
        sb.setSpan(
            AbsoluteSizeSpan(size),
            index,
            index + TEXT_SUB.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )
        return sb
    }

    //设置部分文字的颜色
    private fun getTextForegroundColorSpan(color: Int): Spannable {
        val sb = SpannableStringBuilder(TEXT_CONTENT)
        sb.setSpan(
            ForegroundColorSpan(color),
            index,
            index + TEXT_SUB.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )
        return sb
    }

    //设置部分文字的字体/大小/颜色
    private fun getTextAppearanceSpan(appearance: Int): Spannable {
        val sb = SpannableStringBuilder(TEXT_CONTENT)
        sb.setSpan(
            TextAppearanceSpan(this, appearance),
            index,
            index + TEXT_SUB.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )
        return sb
    }

    //设置部分文字背景色
    private fun getBackgroundColorSpan(color: Int): Spannable {
        val sb = SpannableStringBuilder(TEXT_CONTENT)
        sb.setSpan(
            BackgroundColorSpan(color),
            index,
            index + TEXT_SUB.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )
        return sb
    }

    //设置部分文字添加下划线
    private fun getUnderlineSpan(): Spannable {
        val sb = SpannableStringBuilder(TEXT_CONTENT)
        sb.setSpan(
            UnderlineSpan(),
            index,
            index + TEXT_SUB.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )
        return sb
    }

    //设置部分文字添加删除线
    private fun getStrikethroughSpan(): Spannable {
        val sb = SpannableStringBuilder(TEXT_CONTENT)
        sb.setSpan(
            StrikethroughSpan(),
            index,
            index + TEXT_SUB.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )
        return sb
    }

    //设置部分文字 上下标 Superscript/SubscriptSpan
    private fun getSuperscript_SubscriptSpan(): Spannable {
        val sb = SpannableStringBuilder(TEXT_CONTENT)
        //设置上标文字的字体/大小/颜色
        sb.setSpan(
            TextAppearanceSpan(this, R.style.DateTextOther),
            indexTH,
            indexTH + TEXT_TH.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )
        //设置为上标
        sb.setSpan(
            SuperscriptSpan(),
            indexTH,
            indexTH + TEXT_TH.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )

        //设置下标文字的字体/大小/颜色
        sb.setSpan(
            TextAppearanceSpan(this, R.style.DateTextOther),
            index,
            index + TEXT_SUB.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )
        //设置为下标
        sb.setSpan(
            SubscriptSpan(),
            index,
            index + TEXT_SUB.length,
            Spannable.SPAN_INCLUSIVE_EXCLUSIVE
        )
        return sb
    }
}

Spanable未完待续...

>>URLSpan/ClickableSpan 

>>ReplacementSpan

>>ImageSpan

本文地址：https://blog.csdn.net/qq_20613731/article/details/107500213