diff --git a/app/src/main/java/com/hippo/ehviewer/ui/scene/GalleryCommentsScene.kt b/app/src/main/java/com/hippo/ehviewer/ui/scene/GalleryCommentsScene.kt
index 5b1df2acd..58243a6a8 100644
--- a/app/src/main/java/com/hippo/ehviewer/ui/scene/GalleryCommentsScene.kt
+++ b/app/src/main/java/com/hippo/ehviewer/ui/scene/GalleryCommentsScene.kt
@@ -77,7 +77,7 @@ import com.hippo.ehviewer.dao.Filter
 import com.hippo.ehviewer.ui.MainActivity
 import com.hippo.ehviewer.ui.scene.GalleryListScene.Companion.toStartArgs
 import com.hippo.text.URLImageGetter
-import com.hippo.util.BBCode.toBBCode
+import com.hippo.util.toBBCode
 import com.hippo.util.ExceptionUtils
 import com.hippo.util.ReadableTime
 import com.hippo.util.TextUrl
diff --git a/app/src/main/java/com/hippo/util/BBCode.kt b/app/src/main/java/com/hippo/util/BBCode.kt
index 706ee7735..506b86d2a 100644
--- a/app/src/main/java/com/hippo/util/BBCode.kt
+++ b/app/src/main/java/com/hippo/util/BBCode.kt
@@ -2,70 +2,65 @@ package com.hippo.util
 
 import android.graphics.Typeface
 import android.text.Spanned
-import android.text.style.*
+import android.text.style.CharacterStyle
+import android.text.style.ImageSpan
+import android.text.style.StrikethroughSpan
+import android.text.style.StyleSpan
+import android.text.style.URLSpan
+import android.text.style.UnderlineSpan
 
-object BBCode {
-    fun Spanned.toBBCode(): String {
-        val out = StringBuilder()
-        withinParagraph(out, this, this.length)
-        return out.toString()
-    }
-
-    private fun withinParagraph(out: StringBuilder, text: Spanned, end: Int) {
-        var next: Int
-        var i = 0
-        while (i < text.length) {
-            next = text.nextSpanTransition(i, end, CharacterStyle::class.java)
-            val style = text.getSpans(i, next, CharacterStyle::class.java)
-            for (j in style.indices) {
-                if (style[j] is StyleSpan) {
-                    val s = (style[j] as StyleSpan).style
+fun Spanned.toBBCode(): String {
+    val text = this
+    tailrec fun StringBuilder.processOneSpanTransition(cur: Int = 0) {
+        val next = nextSpanTransition(cur, text.length, CharacterStyle::class.java)
+        getSpans(cur, next, CharacterStyle::class.java).forEach {
+            when (it) {
+                is StyleSpan -> {
+                    val s = it.style
                     if (s and Typeface.BOLD != 0) {
-                        out.append("[b]")
+                        append("[b]")
                     }
                     if (s and Typeface.ITALIC != 0) {
-                        out.append("[i]")
+                        append("[i]")
                     }
                 }
-                if (style[j] is UnderlineSpan) {
-                    out.append("[u]")
+
+                is UnderlineSpan -> append("[u]")
+                is StrikethroughSpan -> append("[s]")
+                is URLSpan -> {
+                    append("[url=")
+                    append(it.url)
+                    append("]")
                 }
-                if (style[j] is StrikethroughSpan) {
-                    out.append("[s]")
-                }
-                if (style[j] is URLSpan) {
-                    out.append("[url=")
-                    out.append((style[j] as URLSpan).url)
-                    out.append("]")
-                }
-                if (style[j] is ImageSpan) {
-                    out.append("[img]")
-                    out.append((style[j] as ImageSpan).source)
-                    out.append("[/img]")
+
+                is ImageSpan -> {
+                    append("[img]")
+                    append(it.source)
+                    append("[/img]")
                 }
             }
-            out.append(text.subSequence(i, next))
-            for (j in style.indices.reversed()) {
-                if (style[j] is URLSpan) {
-                    out.append("[/url]")
-                }
-                if (style[j] is StrikethroughSpan) {
-                    out.append("[/s]")
-                }
-                if (style[j] is UnderlineSpan) {
-                    out.append("[/u]")
-                }
-                if (style[j] is StyleSpan) {
-                    val s = (style[j] as StyleSpan).style
-                    if (s and Typeface.BOLD != 0) {
-                        out.append("[/b]")
-                    }
-                    if (s and Typeface.ITALIC != 0) {
-                        out.append("[/i]")
-                    }
-                }
-            }
-            i = next
         }
+        append(text.subSequence(cur, next))
+        getSpans(cur, next, CharacterStyle::class.java).reversed().forEach {
+            when (it) {
+                is StyleSpan -> {
+                    val s = it.style
+                    if (s and Typeface.BOLD != 0) {
+                        append("[/b]")
+                    }
+                    if (s and Typeface.ITALIC != 0) {
+                        append("[/i]")
+                    }
+                }
+
+                is UnderlineSpan -> append("[/u]")
+                is StrikethroughSpan -> append("[/s]")
+                is URLSpan -> append("[/url]")
+            }
+        }
+        if (next < text.length) processOneSpanTransition(next)
     }
-}
\ No newline at end of file
+    return StringBuilder().apply {
+        processOneSpanTransition()
+    }.toString()
+}