处理颤振中表单字段的更改

Question

How to disable submit button unless forms form fields are edited/changed in flutter dart? I'm able to disable the submit button when form fields are empty but i want to disable it when they are edited

Answer 1

For this king operation use Stream or any state management solutions. this is just a basic example. I hope this may help you.

    var textValue = "";




    TextFormField(
            onChanged :(v){
             textValue =  v;
              setState((){});
           })


RaisedButton(
      onPressed: textValue.isEmpty
                 ? null
                  : () {
                        // do something
                   },
                child: Text("Button"),
                  )

Button will be disabled onPressed has null or not implemented!