Handle dismiss action of Flutter Dismissible.

dismissible_handle_dismiss.dart

handleDismiss(DismissDirection direction, int index) {
    // Get a reference to the swiped item
    final swipedEmail = items[index];

    // Remove it from the list
    items.removeAt(index);

    String action;
    if (direction == DismissDirection.startToEnd) {
      deleteItem();
      action = "Deleted";
    } else {
      archiveItem();
      action = "Archived";
    }
    _scaffoldKey.currentState
        .showSnackBar(
          SnackBar(
            content: Text("$action. Do you want to undo?"),
            duration: Duration(seconds: 5),
            action: SnackBarAction(
                label: "Undo",
                textColor: Colors.yellow,
                onPressed: () {
                  // Deep copy the email
                  final copiedEmail = Email.copy(swipedEmail);
                  // Insert it at swiped position and set state
                  setState(() => items.insert(index, copiedEmail));
                }),
          ),
        )
        .closed
        .then((reason) {
      if (reason != SnackBarClosedReason.action) {
        // The SnackBar was dismissed by some other means
        // that's not clicking of action button
        // Make API call to backend
        
      }
    });
  }