优化

app/src/main/java/io/legado/app/ui/book/changesource/ChangeBookSourceDialog.kt

@@ -298,7 +298,7 @@ class ChangeBookSourceDialog() : BaseDialogFragment(R.layout.dialog_book_change_
         waitDialog.setText(R.string.load_toc)
         waitDialog.show()
         val book = searchBook.toBook()
-        viewModel.getToc(book, {
+        val coroutine = viewModel.getToc(book, {
             waitDialog.dismiss()
             toastOnUi(it)
         }) { toc, source ->
@@ -306,6 +306,9 @@ class ChangeBookSourceDialog() : BaseDialogFragment(R.layout.dialog_book_change_
             callBack?.changeTo(source, book, toc)
             onSuccess?.invoke()
         }
+        waitDialog.setOnCancelListener {
+            coroutine.cancel()
+        }
     }
 
     /**

app/src/main/java/io/legado/app/ui/book/changesource/ChangeBookSourceViewModel.kt

@@ -275,8 +275,8 @@ open class ChangeBookSourceViewModel(application: Application) : BaseViewModel(a
         book: Book,
         onError: (msg: String) -> Unit,
         onSuccess: (toc: List<BookChapter>, source: BookSource) -> Unit
-    ) {
+    ): Coroutine<Pair<List<BookChapter>, BookSource>> {
-        execute {
+        return execute {
             val toc = tocMap[book.bookUrl]
             if (toc != null) {
                 val source = appDb.bookSourceDao.getBookSource(book.origin)