优化

app/src/main/java/io/legado/app/model/AudioPlay.kt

@@ -114,28 +114,30 @@ object AudioPlay {
     fun prev(context: Context) {
         Coroutine.async {
             book?.let { book ->
-                if (book.durChapterIndex <= 0) {
-                    return@let
-                }
+                if (book.durChapterIndex > 0) {
                     book.durChapterIndex = book.durChapterIndex - 1
                     book.durChapterPos = 0
                     durChapter = null
                     saveRead()
                     play(context)
+                } else {
+                    stop(context)
+                }
             }
         }
     }
 
     fun next(context: Context) {
         book?.let { book ->
-            if (book.durChapterIndex >= book.totalChapterNum) {
-                return@let
-            }
+            if (book.durChapterIndex + 1 < book.totalChapterNum) {
                 book.durChapterIndex = book.durChapterIndex + 1
                 book.durChapterPos = 0
                 durChapter = null
                 saveRead()
                 play(context)
+            } else {
+                stop(context)
+            }
         }
     }
 

app/src/main/java/io/legado/app/ui/book/audio/AudioPlayActivity.kt

@@ -269,6 +269,10 @@ class AudioPlayActivity :
         }
         observeEventSticky<String>(EventBus.AUDIO_SUB_TITLE) {
             binding.tvSubTitle.text = it
+            AudioPlay.book?.let { book ->
+                binding.ivSkipPrevious.isEnabled = book.durChapterIndex > 0
+                binding.ivSkipNext.isEnabled = book.durChapterIndex < book.totalChapterNum - 1
+            }
         }
         observeEventSticky<Int>(EventBus.AUDIO_SIZE) {
             binding.playerProgress.max = it