Ask to delete local messages

app/src/main/java/eu/faircode/email/AdapterFolder.java

@@ -343,7 +343,17 @@ public class AdapterFolder extends RecyclerView.Adapter<AdapterFolder.ViewHolder
                     }.execute(context, owner, args, "folder:sync");
                 }
 
-                private void OnActionDeleteLocal(boolean browsed) {
+                private void OnActionDeleteLocal(final boolean browsed) {
+                    View dview = LayoutInflater.from(context).inflate(R.layout.dialog_message, null);
+                    TextView tvMessage = dview.findViewById(R.id.tvMessage);
+
+                    tvMessage.setText(context.getText(R.string.title_ask_delete_local));
+
+                    new DialogBuilderLifecycle(context, owner)
+                            .setView(dview)
+                            .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
+                                @Override
+                                public void onClick(DialogInterface dialog, int which) {
                                     Bundle args = new Bundle();
                                     args.putLong("id", folder.id);
                                     args.putBoolean("browsed", browsed);
@@ -367,6 +377,10 @@ public class AdapterFolder extends RecyclerView.Adapter<AdapterFolder.ViewHolder
                                         }
                                     }.execute(context, owner, args, "folder:delete:local");
                                 }
+                            })
+                            .setNegativeButton(android.R.string.cancel, null)
+                            .show();
+                }
 
                 private void onActionEmptyTrash() {
                     new DialogBuilderLifecycle(context, owner)

app/src/main/res/values/strings.xml

@@ -373,6 +373,7 @@
     <string name="title_ask_show_html">Showing the original message can leak privacy sensitive information</string>
     <string name="title_ask_show_image">Showing images can leak privacy sensitive information</string>
     <string name="title_ask_edit_ref">Edit reformatted replied/forwarded message text?</string>
+    <string name="title_ask_delete_local">Delete local messages which are stored on the remote server too?</string>
 
     <string name="title_compose">Compose</string>
     <string name="title_from">From:</string>