Only remove PendingContact from UI when removed from DB

bramble-api/src/main/java/org/briarproject/bramble/api/contact/ContactManager.java

@@ -79,8 +79,10 @@ public interface ContactManager {
 	/**
 	 * Removes a {@link PendingContact} that is in state
 	 * {@link PendingContactState FAILED}.
+	 * @param commitAction an action to run on the main thread after removing.
 	 */
-	void removePendingContact(PendingContact pendingContact) throws DbException;
+	void removePendingContact(PendingContact pendingContact,
+			Runnable commitAction) throws DbException;
 
 	/**
 	 * Returns the contact with the given ID.

bramble-core/src/main/java/org/briarproject/bramble/contact/ContactManagerImpl.java

@@ -222,9 +222,15 @@ class ContactManagerImpl implements ContactManager {
 	}
 
 	@Override
-	public void removePendingContact(PendingContact pendingContact) {
+	public void removePendingContact(PendingContact pendingContact,
+			Runnable commitAction) throws DbException {
 		// TODO replace with real implementation
 		pendingContacts.remove(pendingContact);
+		try {
+			Thread.sleep(250);
+		} catch (InterruptedException ignored) {
+		}
+		db.transaction(true, txn -> txn.attach(commitAction));
 	}
 
 	@Override

briar-android/src/main/java/org/briarproject/briar/android/contact/add/remote/PendingContactListActivity.java

@@ -86,8 +86,8 @@ public class PendingContactListActivity extends BriarActivity
 
 	@Override
 	public void onFailedPendingContactRemoved(PendingContact pendingContact) {
-		adapter.remove(pendingContact);
-		viewModel.removePendingContact(pendingContact);
+		viewModel.removePendingContact(pendingContact,
+				() -> adapter.remove(pendingContact));
 	}
 
 	private void onPendingContactsChanged(Collection<PendingContact> contacts) {

briar-android/src/main/java/org/briarproject/briar/android/contact/add/remote/PendingContactListViewModel.java

@@ -81,10 +81,12 @@ public class PendingContactListViewModel extends AndroidViewModel
 		return pendingContacts;
 	}
 
-	void removePendingContact(PendingContact pendingContact) {
+	void removePendingContact(PendingContact pendingContact,
+			Runnable commitAction) {
 		dbExecutor.execute(() -> {
 			try {
-				contactManager.removePendingContact(pendingContact);
+				contactManager
+						.removePendingContact(pendingContact, commitAction);
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 			}