修复webDav连接不上时webDav界面无响应的bug

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

@@ -65,11 +65,8 @@ import io.legado.app.ui.widget.PopupAction
 import io.legado.app.ui.widget.dialog.PhotoDialog
 import io.legado.app.ui.widget.dialog.TextDialog
 import io.legado.app.utils.*
+import kotlinx.coroutines.*
 import kotlinx.coroutines.Dispatchers.IO
-import kotlinx.coroutines.Job
-import kotlinx.coroutines.delay
-import kotlinx.coroutines.isActive
-import kotlinx.coroutines.launch
 
 class ReadBookActivity : BaseReadBookActivity(),
     View.OnTouchListener,
@@ -1063,9 +1060,11 @@ class ReadBookActivity : BaseReadBookActivity(),
         backupJob?.cancel()
         backupJob = launch {
             delay(120000)
-            ReadBook.book?.let {
-                AppWebDav.uploadBookProgress(it)
-                Backup.autoBack(this@ReadBookActivity)
+            withContext(IO) {
+                ReadBook.book?.let {
+                    AppWebDav.uploadBookProgress(it)
+                    Backup.autoBack(this@ReadBookActivity)
+                }
             }
         }
     }