优化

app/src/main/java/io/legado/app/ui/book/read/ReadBookActivity.kt

@@ -938,7 +938,7 @@ class ReadBookActivity : BaseReadBookActivity(),
             }
         }
 
-        if (previousResult.chapterIndex != searchResult.chapterIndex) {
+        if (searchResult.chapterIndex != previousResult?.chapterIndex) {
             viewModel.openChapter(searchResult.chapterIndex) {
                 jumpToPosition()
             }

app/src/main/java/io/legado/app/ui/book/read/SearchMenu.kt

@@ -46,8 +46,8 @@ class SearchMenu @JvmOverloads constructor(
         get() = searchResultList.isNotEmpty()
     val selectedSearchResult: SearchResult?
         get() = searchResultList.getOrNull(currentSearchResultIndex)
-    val previousSearchResult: SearchResult
-        get() = searchResultList[lastSearchResultIndex]
+    val previousSearchResult: SearchResult?
+        get() = searchResultList.getOrNull(lastSearchResultIndex)
 
     init {
         initAnimation()