Enable R8 and fix errors.

app/src/main/java/com/etesync/syncadapter/ui/AccountListFragment.kt

@@ -47,7 +47,7 @@ class AccountListFragment : ListFragment(), LoaderManager.LoaderCallbacks<Array<
     }
 
     override fun onItemClick(parent: AdapterView<*>, view: View, position: Int, id: Long) {
-        val account = listAdapter.getItem(position) as Account
+        val account = listAdapter?.getItem(position) as Account
 
         val intent = Intent(context, AccountActivity::class.java)
         intent.putExtra(AccountActivity.EXTRA_ACCOUNT, account)

app/src/main/java/com/etesync/syncadapter/ui/CollectionMembersListFragment.kt

@@ -104,7 +104,7 @@ class CollectionMembersListFragment : ListFragment(), AdapterView.OnItemClickLis
     }
 
     override fun onItemClick(parent: AdapterView<*>, view: View, position: Int, id: Long) {
-        val member = listAdapter.getItem(position) as JournalManager.Member
+        val member = listAdapter?.getItem(position) as JournalManager.Member
 
         AlertDialog.Builder(activity!!)
                 .setIcon(R.drawable.ic_info_dark)

app/src/main/java/com/etesync/syncadapter/ui/importlocal/ImportActivity.kt

@@ -103,7 +103,7 @@ class ImportActivity : BaseActivity(), SelectImportMethod, ResultFragment.OnImpo
 
         private var mSelectImportMethod: SelectImportMethod? = null
 
-        override fun onAttach(context: Context?) {
+        override fun onAttach(context: Context) {
             super.onAttach(context)
             // This makes sure that the container activity has implemented
             // the callback interface. If not, it throws an exception
@@ -115,14 +115,14 @@ class ImportActivity : BaseActivity(), SelectImportMethod, ResultFragment.OnImpo
 
         }
 
-        override fun onAttach(activity: Activity?) {
+        override fun onAttach(activity: Activity) {
             super.onAttach(activity)
             // This makes sure that the container activity has implemented
             // the callback interface. If not, it throws an exception
             try {
                 mSelectImportMethod = activity as SelectImportMethod?
             } catch (e: ClassCastException) {
-                throw ClassCastException(activity!!.toString() + " must implement MyInterface ")
+                throw ClassCastException(activity.toString() + " must implement MyInterface ")
             }
 
         }

app/src/main/java/com/etesync/syncadapter/ui/importlocal/ResultFragment.kt

@@ -22,7 +22,7 @@ class ResultFragment : DialogFragment() {
         result = arguments!!.getSerializable(KEY_RESULT) as ImportResult
     }
 
-    override fun onDismiss(dialog: DialogInterface?) {
+    override fun onDismiss(dialog: DialogInterface) {
         super.onDismiss(dialog)
         val activity = activity
         if (activity is DialogInterface) {

app/src/main/java/com/etesync/syncadapter/ui/journalviewer/ListEntriesFragment.kt

@@ -87,7 +87,7 @@ class ListEntriesFragment : ListFragment(), AdapterView.OnItemClickListener {
     }
 
     override fun onItemClick(parent: AdapterView<*>, view: View, position: Int, id: Long) {
-        val entry = listAdapter.getItem(position) as EntryEntity
+        val entry = listAdapter?.getItem(position) as EntryEntity
         startActivity(JournalItemActivity.newIntent(context!!, account, info, entry.content))
     }
 

gradle.properties

@@ -1,4 +1,3 @@
 android.enableJetifier=true
 android.useAndroidX=true
-android.enableR8 = false
 org.gradle.jvmargs=-Xmx2048M