public class ForegroundColorSpan extends CharacterStyle
        implements UpdateAppearance, ParcelableSpan {

    private final int mColor;

    public ForegroundColorSpan(@ColorInt int color) {
        mColor = color;
    }
    ....... 忽略無(wú)關(guān)代碼
   
    @ColorInt
    public int getForegroundColor() {
        return mColor;
    }
    /// 重要函數(shù)
    @Override
    public void updateDrawState(@NonNull TextPaint textPaint) {
        textPaint.setColor(mColor);
    }
}

class MutableForegroundColorSpan : ForegroundColorSpan {
    // 動(dòng)畫(huà)漸變值預(yù)設(shè)
    companion object {
        val MUTABLE_FOREGROUND_COLOR_SPAN_FC_PROPERTY: Property<MutableForegroundColorSpan, Int> =
            object : Property<MutableForegroundColorSpan, Int>(
                Int::class.java, "MUTABLE_FOREGROUND_COLOR_SPAN_FC_PROPERTY"
            ) {
                override operator fun set(span: MutableForegroundColorSpan, value: Int) {
                    span.foregroundColor = value
                }

                override operator fun get(span: MutableForegroundColorSpan): Int {
                    return span.foregroundColor
                }
            }
    }

    private var mAlpha = 255
    private var mForegroundColor: Int

    constructor(alpha: Int, color: Int) : super(color) {
        mAlpha = alpha
        mForegroundColor = color
    }
    // 原構(gòu)造函數(shù)繼承
    constructor(src: Parcel): super(src) {

        mForegroundColor = src.readInt()
        mAlpha = src.readInt()
    }

    override fun writeToParcel(dest: Parcel, flags: Int) {
        super.writeToParcel(dest, flags)
        dest.writeInt(mForegroundColor)
        dest.writeInt(mAlpha)
    }
    // 動(dòng)畫(huà)設(shè)置
    fun animationColorChange(startColor: Int,endColor:Int) : ObjectAnimator{
        val objectAnimator: ObjectAnimator = ObjectAnimator.ofInt(
            this,
            MutableForegroundColorSpan.MUTABLE_FOREGROUND_COLOR_SPAN_FC_PROPERTY,
            startColor,
            endColor
        )
        objectAnimator.setEvaluator(ArgbEvaluator())
        objectAnimator.duration = 3000
        return objectAnimator
    }

    // 透明度
    fun setAlpha(alpha: Int) {
        mAlpha = alpha
    }

    fun setForegroundColor(foregroundColor: Int) {
        mForegroundColor = foregroundColor
    }

    // 更新畫(huà)筆顏色
    override fun updateDrawState(ds: TextPaint) {
        ds.color = foregroundColor
    }
     // 獲取文本顏色
    override fun getForegroundColor(): Int {
        return Color.argb(
            mAlpha,
            Color.red(mForegroundColor),
            Color.green(mForegroundColor),
            Color.blue(mForegroundColor)
        )
    }
   
}
 // 樣式設(shè)置 監(jiān)聽(tīng)動(dòng)畫(huà)回調(diào)重新設(shè)置樣式從而刷新文本
private var mutableForegroundColorSpan =
    MutableForegroundColorSpan(255, Color.BLACK)
mutableForegroundColorSpan.animationColorChange(
    Color.BLACK,
    Color.RED
).run {
    addUpdateListener {
        mutableForegroundColorView.text = animationColor()
    }
    start()
}

// 文本樣式配置
private fun animationColor(): SpannableStringBuilder {
    var spannableString = SpannableStringBuilder("")
    spannableString.also { span ->
        span.append(SpannableString("xxxxMutableForegroundColorSpanyyyy").also {
            it.setSpan(
                mutableForegroundColorSpan,
                4,
                "MutableForegroundColorSpan".length,
                Spannable.SPAN_EXCLUSIVE_EXCLUSIVE
            )
        })
    }
    return spannableString
}