优化

app/src/main/java/io/legado/app/ui/book/info/BookInfoActivity.kt

@@ -300,9 +300,7 @@ class BookInfoActivity :
             }
         }
         tvChangeSource.setOnClickListener {
-            viewModel.bookData.value?.let {
+            showDialogFragment(ChangeBookSourceDialog(viewModel.name, viewModel.author))
-                showDialogFragment(ChangeBookSourceDialog(it.name, it.author))
-            }
         }
         tvTocView.setOnClickListener {
             if (!viewModel.inBookshelf) {

app/src/main/java/io/legado/app/ui/book/info/BookInfoViewModel.kt

@@ -27,6 +27,8 @@ import kotlinx.coroutines.Dispatchers.IO
 class BookInfoViewModel(application: Application) : BaseViewModel(application) {
     val bookData = MutableLiveData<Book>()
     val chapterListData = MutableLiveData<List<BookChapter>>()
+    var name = ""
+    var author = ""
     var durChapterIndex = 0
     var inBookshelf = false
     var bookSource: BookSource? = null
@@ -34,8 +36,8 @@ class BookInfoViewModel(application: Application) : BaseViewModel(application) {
 
     fun initData(intent: Intent) {
         execute {
-            val name = intent.getStringExtra("name") ?: ""
+            name = intent.getStringExtra("name") ?: ""
-            val author = intent.getStringExtra("author") ?: ""
+            author = intent.getStringExtra("author") ?: ""
             val bookUrl = intent.getStringExtra("bookUrl") ?: ""
             appDb.bookDao.getBook(name, author)?.let {
                 inBookshelf = true