Let TextEditingController be null in null_safety

Question

I have converted my project to null-safety Dart 2. I have been working through issues since the conversion. Right now, I need to change this line

clientFNameController.text = widget.trxns!['clientFName'];

so that

clientFNameController.text = null;

This is the line where the controller is declared:

final clientNameController = TextEditingController();

I have tried this

clientFNameController?.text = widget.trxns!['clientFName'];

and this

clientFNameController.text = widget.trxns?['clientFName'];

How do I write the this line

  clientFNameController.text = widget.trxns['clientFName'];

so this can be true

clientFNameController.text = null;

Answer 1

You cannot set the text property of a TextEditingController to null, since the type of the setter is String, not String?.

You can use the empty string "" however. For example, if you wanted your text field to have the text of widget.trxnw['clientFName'] if it was non-null, and be empty otherwise, you could have something like this:

String? clientFName = widget.trxnw['clientFName'];
if (clientFName == null) {
  clientFNameController.text = "";
} else {
  clientFNameController.text = clientFName;
}

This can be shortened to:

String clientFName = widget.trxns['clientFName'] ?? "";  // "if null" operator
clientFNameController.text = clientFName;

Or shortened even further to:

clientFNameController.text = widget.trxns['clientFName'] ?? "";