优化

app/src/main/java/io/legado/app/ui/book/local/ImportBookActivity.kt

@@ -235,12 +235,15 @@ class ImportBookActivity : VMBaseActivity<ImportBookViewModel>(R.layout.activity
      * 扫描当前文件夹
      */
     private fun scanFolder() {
+        launch(IO) {
             rootDoc?.let { doc ->
                 adapter.clearItems()
                 val lastDoc = subDocs.lastOrNull() ?: doc
                 viewModel.scanDoc(lastDoc) {
+                    launch {
                         adapter.addItem(it)
                     }
+                }
             } ?: let {
                 val lastPath = AppConfig.importBookPath
                 if (lastPath.isNullOrEmpty()) {
@@ -249,11 +252,14 @@ class ImportBookActivity : VMBaseActivity<ImportBookViewModel>(R.layout.activity
                     adapter.clearItems()
                     val file = File(path)
                     viewModel.scanFile(file) {
+                        launch {
                             adapter.addItem(it)
                         }
                     }
                 }
             }
+        }
+    }
 
     override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
         super.onActivityResult(requestCode, resultCode, data)

app/src/main/java/io/legado/app/ui/book/local/ImportBookViewModel.kt

@@ -34,7 +34,6 @@ class ImportBookViewModel(application: Application) : BaseViewModel(application)
     }
 
     fun scanDoc(documentFile: DocumentFile, find: (docItem: DocItem) -> Unit) {
-        execute {
         val docList = DocumentUtils.listFiles(context, documentFile.uri)
         docList.forEach { docItem ->
             if (docItem.isDir) {
@@ -48,10 +47,8 @@ class ImportBookViewModel(application: Application) : BaseViewModel(application)
             }
         }
     }
-    }
 
     fun scanFile(file: File, find: (docItem: DocItem) -> Unit) {
-        execute {
         file.listFiles()?.forEach {
             if (it.isDirectory) {
                 scanFile(it, find)
@@ -70,6 +67,5 @@ class ImportBookViewModel(application: Application) : BaseViewModel(application)
             }
         }
     }
-    }
 
 }