优化

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

@@ -68,7 +68,7 @@ class BookInfoViewModel(application: Application) : BaseViewModel(application) {
                             toastOnUi(R.string.error_get_book_info)
                         }
                 } ?: let {
-                    chapterListData.postValue(null)
+                    chapterListData.postValue(emptyList())
                     toastOnUi(R.string.error_no_source)
                 }
             }
@@ -104,11 +104,11 @@ class BookInfoViewModel(application: Application) : BaseViewModel(application) {
                                 toastOnUi(R.string.chapter_list_empty)
                             }
                         }.onError {
-                            chapterListData.postValue(null)
+                            chapterListData.postValue(emptyList())
                             toastOnUi(R.string.error_get_chapter_list)
                         }
                 } ?: let {
-                    chapterListData.postValue(null)
+                    chapterListData.postValue(emptyList())
                     toastOnUi(R.string.error_no_source)
                 }
             }

app/src/main/java/io/legado/app/ui/config/BackupRestoreUi.kt

@@ -3,7 +3,6 @@ package io.legado.app.ui.config
 import android.app.Activity.RESULT_OK
 import android.content.Intent
 import android.net.Uri
-import androidx.activity.result.contract.ActivityResultContracts
 import androidx.documentfile.provider.DocumentFile
 import androidx.fragment.app.Fragment
 import io.legado.app.R
@@ -104,13 +103,17 @@ object BackupRestoreUi {
     }
 
     private fun restoreUsePermission(fragment: Fragment, path: String) {
-        fragment.registerForActivityResult(ActivityResultContracts.RequestMultiplePermissions()) {
+        PermissionsCompat.Builder(fragment)
+            .addPermissions(*Permissions.Group.STORAGE)
+            .rationale(R.string.tip_perm_request_storage)
+            .onGranted {
                 Coroutine.async {
                     AppConfig.backupPath = path
                     Restore.restoreDatabase(path)
                     Restore.restoreConfig(path)
                 }
-        }.launch(Permissions.Group.STORAGE)
+            }
+            .request()
     }
 
     fun importOldData(fragment: Fragment) {

app/src/main/java/io/legado/app/ui/rss/read/ReadRssViewModel.kt

@@ -53,7 +53,7 @@ class ReadRssViewModel(application: Application) : BaseViewModel(application),
                     rssArticle = rssStar?.toRssArticle() ?: appDb.rssArticleDao.get(origin, link)
                     rssArticle?.let { rssArticle ->
                         if (!rssArticle.description.isNullOrBlank()) {
-                            contentLiveData.postValue(rssArticle.description)
+                            contentLiveData.postValue(rssArticle.description!!)
                         } else {
                             rssSource?.let {
                                 val ruleContent = it.ruleContent