修复bug

app/src/main/java/io/legado/app/ui/book/changecover/ChangeCoverDialog.kt

@@ -7,7 +7,6 @@ import android.view.View
 import android.view.ViewGroup
 import androidx.appcompat.widget.Toolbar
 import androidx.fragment.app.FragmentManager
-import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.GridLayoutManager
 import io.legado.app.R
 import io.legado.app.base.BaseDialogFragment
@@ -93,9 +92,7 @@ class ChangeCoverDialog : BaseDialogFragment(),
             binding.toolBar.menu.applyTint(requireContext(), Theme.getTheme())
         })
         viewModel.searchBooksLiveData.observe(viewLifecycleOwner, {
-            val diffResult = DiffUtil.calculateDiff(DiffCallBack(adapter.getItems(), it))
             adapter.setItems(it)
-            diffResult.dispatchUpdatesTo(adapter)
         })
     }
 

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

@@ -5,7 +5,6 @@ import android.view.*
 import androidx.appcompat.widget.SearchView
 import androidx.appcompat.widget.Toolbar
 import androidx.fragment.app.FragmentManager
-import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import io.legado.app.App
@@ -145,9 +144,7 @@ class ChangeSourceDialog : BaseDialogFragment(),
             binding.toolBar.menu.applyTint(requireContext())
         })
         viewModel.searchBooksLiveData.observe(viewLifecycleOwner, {
-            val diffResult = DiffUtil.calculateDiff(DiffCallBack(adapter.getItems(), it))
             adapter.setItems(it)
-            diffResult.dispatchUpdatesTo(adapter)
         })
         App.db.bookSourceDao.liveGroupEnabled().observe(this, {
             groups.clear()

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

@@ -102,7 +102,7 @@ class ChangeSourceViewModel(application: Application) : BaseViewModel(applicatio
     private fun startSearch() {
         execute {
             bookSourceList.clear()
-            if (searchGroup.isNullOrBlank()) {
+            if (searchGroup.isBlank()) {
                 bookSourceList.addAll(App.db.bookSourceDao.allEnabled)
             } else {
                 bookSourceList.addAll(App.db.bookSourceDao.getEnabledByGroup(searchGroup))