how to set textfield width based on it's text in flutter

Question

I want to size the textfield based on text length...while typing it's length should be changed according to text..I was suggested to use IntrinsicWidth but its not working..

Container(
              height: 300,
              decoration: BoxDecoration(
                  color: Colors.white,
                  borderRadius: BorderRadius.circular(30)
              ),
              child: Center(
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    Padding(
                      padding: const EdgeInsets.symmetric(horizontal: 40.0),
                      child: IntrinsicWidth(
                        child: TextField(
                          keyboardType: TextInputType.number,
                          textAlign: TextAlign.center,
                          style: TextStyle(
                            fontSize: 30,
                          ),

                          decoration: InputDecoration(
                              hintStyle: TextStyle(fontSize: 20,color: Colors.grey[400]),
                              hintText: 'Enter Income Amount'
                          ),
                        ),
                      ),
                    ),

Answer 1

Create a TextEditingController instance and call setState to update the UI. I am changing hintText to null based on userInput.

 final TextEditingController controller = TextEditingController();
 .....

Padding(
  padding: const EdgeInsets.symmetric(horizontal: 40.0),
  child: IntrinsicWidth(
    child: TextField(
      textAlign: TextAlign.center,
      controller: controller,
      onChanged: (value) {
        setState(() {});
      },
      style: TextStyle(
        fontSize: 30,
      ),
      decoration: InputDecoration(
        hintStyle: TextStyle(fontSize: 20, color: Colors.grey[400]),
        hintText:
            controller.text.isEmpty ? 'Enter Income Amount' : null,
      ),
    ),
  ),
),