diff --git a/app/src/main/java/io/legado/app/help/BookHelp.kt b/app/src/main/java/io/legado/app/help/BookHelp.kt
index 9fc9206d1..c121e1781 100644
--- a/app/src/main/java/io/legado/app/help/BookHelp.kt
+++ b/app/src/main/java/io/legado/app/help/BookHelp.kt
@@ -6,10 +6,13 @@ import io.legado.app.data.entities.BookChapter
 import io.legado.app.data.entities.ReplaceRule
 import io.legado.app.utils.getPrefInt
 import io.legado.app.utils.getPrefString
+import io.legado.app.utils.similarity
 import java.io.BufferedWriter
 import java.io.File
 import java.io.FileWriter
 import java.io.IOException
+import kotlin.math.max
+import kotlin.math.min
 
 object BookHelp {
 
@@ -90,8 +93,28 @@ object BookHelp {
             ?: ""
     }
 
-    fun getDurChapterIndexByChapterName() {
-
+    fun getDurChapterIndexByChapterTitle(
+        title: String,
+        index: Int,
+        chapters: List<BookChapter>
+    ): Int {
+        if (chapters.size > index && title == chapters[index].title) {
+            return index
+        }
+        var similarity = 0F
+        var newIndex = index
+        val start = max(index - 10, 0)
+        val end = min(index + 10, chapters.size - 1)
+        if (start < end) {
+            for (i in start..end) {
+                val s = title.similarity(chapters[i].title)
+                if (s > similarity) {
+                    similarity = s
+                    newIndex = i
+                }
+            }
+        }
+        return newIndex
     }
 
     var bookName: String? = null
diff --git a/app/src/main/java/io/legado/app/ui/changesource/ChangeSourceDialog.kt b/app/src/main/java/io/legado/app/ui/changesource/ChangeSourceDialog.kt
index 15e830033..b4ff6b8ba 100644
--- a/app/src/main/java/io/legado/app/ui/changesource/ChangeSourceDialog.kt
+++ b/app/src/main/java/io/legado/app/ui/changesource/ChangeSourceDialog.kt
@@ -117,8 +117,8 @@ class ChangeSourceDialog : DialogFragment(),
                 if (book.coverUrl.isNullOrEmpty()) {
                     book.coverUrl = oldBook.getDisplayCover()
                 }
+                activity.changeTo(book)
             }
-            activity.changeTo(book)
         }
         dismiss()
     }
diff --git a/app/src/main/java/io/legado/app/utils/StringExtensions.kt b/app/src/main/java/io/legado/app/utils/StringExtensions.kt
index 0100b5f9f..856a6c2d9 100644
--- a/app/src/main/java/io/legado/app/utils/StringExtensions.kt
+++ b/app/src/main/java/io/legado/app/utils/StringExtensions.kt
@@ -1,5 +1,7 @@
 package io.legado.app.utils
 
+import kotlin.math.min
+
 // import org.apache.commons.text.StringEscapeUtils
 
 fun String?.safeTrim() = if (this.isNullOrBlank()) null else this.trim()
@@ -33,4 +35,39 @@ fun String.splitNotBlank(regex: Regex, limit: Int = 0): Array<String> = run {
 
 fun String.startWithIgnoreCase(start: String): Boolean {
     return if (this.isBlank()) false else startsWith(start, true)
-}
\ No newline at end of file
+}
+
+
+fun String.similarity(target: String): Float {
+    //计算两个字符串的长度。
+    val len1 = this.length
+    val len2 = target.length
+    //建立上面说的数组，比字符长度大一个空间
+    val dif = Array(len1 + 1) { IntArray(len2 + 1) }
+    //赋初值，步骤B。
+    for (a in 0..len1) {
+        dif[a][0] = a
+    }
+    for (a in 0..len2) {
+        dif[0][a] = a
+    }
+    //计算两个字符是否一样，计算左上的值
+    var temp: Int
+    for (i in 1..len1) {
+        for (j in 1..len2) {
+            temp = if (this[i - 1] == target[j - 1]) {
+                0
+            } else {
+                1
+            }
+            //取三个值中最小的
+            dif[i][j] = min(
+                min(dif[i - 1][j - 1] + temp, dif[i][j - 1] + 1),
+                dif[i - 1][j] + 1
+            )
+        }
+    }
+    //计算相似度
+    return 1 - dif[len1][len2].toFloat() / Math.max(length, target.length)
+}
+