Flutter Text Field: How to add Icon inside the border

I would like to add the icon in the search bar. Here is my code so far:

new TextField(
     decoration: new InputDecoration(
     icon: new Icon(Icons.search)
     labelText: "Describe Your Issue...",
     enabledBorder: const OutlineInputBorder(
     borderRadius: BorderRadius.all(Radius.circular(20.0)),
     borderSide: const BorderSide(
       color: Colors.grey,
      ),
    ),
    focusedBorder: OutlineInputBorder(
      borderRadius: BorderRadius.all(Radius.circular(10.0)),
      borderSide: BorderSide(color: Colors.blue),
    ),
   ),
  ),

This is the result of the code above (this is not what i want):

Edited Answer

Updating answer as my original answer doesn't actually cover the original context of the question.

You can use the prefixIcon in the TextField or in the TextFormField to get some widget as a leading in your TextField.

Example

    TextField(
//    ...,other fields
      decoration: InputDecoration(
        prefixIcon: prefixIcon??Icon(Icons.done),
      ),
    ),

> PS: Do not get confuse between prefixIcon and prefix as this two > are different things. > https://api.flutter.dev/flutter/material/InputDecoration/prefix.html

Also if you want to achieve something like floating app bar then you can refer to my original answer.

Original answer

You can use my Flutter package to implement Floating AppBar in your application.

You need to add below package in your pub.

rounded_floating_app_bar: ^0.1.0

run $ flutter packages get from the command line.

Now in your Dart code, you can use:

import 'package:rounded_floating_app_bar/rounded_floating_app_bar.dart';
...
NestedScrollView(
  headerSliverBuilder: (context, isInnerBoxScroll) {
    return [
      RoundedFloatingAppBar(
        floating: true,
        snap: true,
        title: TextField(
          decoration: InputDecoration(
            prefixIcon: Icon(Icons.search),
            border: InputBorder.none,
          ),
        ),
      ),
    ];
  },
  body: Container(),
),

Output:

Use the prefixIcon in Just adjust in Boarder Radius

import 'package:flutter/material.dart';

class TextFieldShow extends StatelessWidget {
  TextEditingController _controller = TextEditingController();
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: new Text("Tab demo"),
      ),
      body: Padding(
        padding: const EdgeInsets.all(8.0),
        child: TextField(
            style: TextStyle(
              fontSize: 25.0,
              color: Colors.blueAccent,
            ),
            decoration: InputDecoration(
                contentPadding: EdgeInsets.fromLTRB(20.0, 15.0, 20.0, 15.0),
                prefixIcon: Icon(Icons.people),
                hintText: "Enter Your Name",
                border: OutlineInputBorder(
                    borderSide: BorderSide(color: Colors.blueAccent, width: 32.0),
                    borderRadius: BorderRadius.circular(25.0)),
                focusedBorder: OutlineInputBorder(
                    borderSide: BorderSide(color: Colors.white, width: 32.0),
                    borderRadius: BorderRadius.circular(25.0)))),
      ),
    );
  }
}

Try this way (using prefixIcon), just adjust the border radius

TextField(
          style: TextStyle(fontSize: 25.0),
          decoration: InputDecoration(
          	contentPadding: EdgeInsets.fromLTRB(20.0, 15.0, 20.0, 15.0),
          	prefixIcon: Icon(Icons.search),
          	hintText: "Describe your issue",
          	border: OutlineInputBorder(
            		borderSide: BorderSide(color: Colors.red[300], width: 32.0),
            		borderRadius: BorderRadius.circular(25.0)
	          ),
          	focusedBorder: OutlineInputBorder(
              		borderSide: BorderSide(color: Colors.red[300], width: 32.0),
              		borderRadius: BorderRadius.circular(25.0)))

Hope this help.

use prefixicon

return TextFormField(
  decoration: InputDecoration(
    hintText: hint,
    labelText: label,
    prefixIcon: Icon(Icons.person),
    contentPadding: EdgeInsets.fromLTRB(20.0, 10.0, 20.0, 10.0),
  ),
);

You can use the InputDecoration argument prefixIcon, or suffixIcon.

prefixIcon will show before the text inside your TextField.

TextField(
  decoration: InputDecoration(
    prefixIcon: Icon(Icons.done),
  ),
);

prefixIcon showcase

OR

suffixIcon will show after the text inside your TextField.

TextField(
  decoration: InputDecoration(
    suffixIcon: Icon(Icons.done),
  ),
);

suffixIcon showcase

ATTN: Code above does not include the border styling that is shown on the screenshots :)

You can try this:

Container(
  decoration: BoxDecoration(
    border: Border.all(
      color: Colors.grey.withOpacity(0.5),
      width: 1.0,
    ),
    borderRadius: BorderRadius.circular(4.0),
  ),
  margin: EdgeInsets.all(12),
  child: Row(
    children: <Widget>[
      Padding(
        padding: EdgeInsets.only(left: 8),
        child: Icon(
          Icons.search,
          color: Colors.grey,
          size: 20,
        ),
      ),
      new Expanded(
        child: TextField(
          keyboardType: TextInputType.text,
          decoration: InputDecoration(
            border: InputBorder.none,
            hintText: "Search by Name",
            hintStyle: TextStyle(color: Colors.grey),
            contentPadding:
                EdgeInsets.symmetric(vertical: 8, horizontal: 8),
            isDense: true,
          ),
          style: TextStyle(
            fontSize: 14.0,
            color: Colors.black,
          ),
        ),
      )
    ],
  ),
)

It will be displayed as:

If you need to ad an icon in the Textfield use the arguments prefixIcon and suffixIcon inside it, like

TextField(
  decoration: InputDecoration(
    prefixIcon: Icon(Icons.mail),
    suffixIcon: Icon(Icons.search),
  ),
);

TextField(
      decoration: InputDecoration(
        filled: true,
        fillColor: Color(0xFFFFFFFF),
        prefixIcon: Icon(Icons.search, color: Colors.pink),
        border: OutlineInputBorder(
          borderRadius: BorderRadius.all(
            Radius.circular(30),
          ),
        ),
        hintText: ' Search',
      ),
    ),