Flutter all button explain






import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
          appBar: AppBar(
            actions: [
              Icon(
                Icons.menu,
                color: Colors.black,
              )
            ],
            backgroundColor: Colors.red,
            elevation: .0,
          ),
          body: Padding(
            padding: EdgeInsets.only(
              top: 50.0,
              left: 140.0,
            ),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.center,
              children: [
                FlatButton(
                  onPressed: () {
                    print("I am flat");
                  },
                  child: Text("OnPressed"),
                  color: Colors.tealAccent,
                  shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(18.0)),
                ),
                SizedBox(
                  height: 10,
                ),
                FlatButton.icon(
                  icon: Icon(Icons.settings),
                  label: Text("Flat icon btn"),
                  onPressed: () {
                    print("icon btn");
                  },
                  color: Colors.tealAccent,
                  shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(18.0)),
                ),
                SizedBox(
                  height: 10.0,
                ),
                Container(
                  width: 60,
                  height: 60,
                  decoration: BoxDecoration(shape: BoxShape.circle),
                  child: RaisedButton(
                    onPressed: () {},
                    elevation: 12.0,
                    color: Colors.tealAccent,
                    child: Icon(Icons.access_alarm_outlined),
                    shape: RoundedRectangleBorder(
                        borderRadius: BorderRadius.circular(89)),
                  ),
                ),
                SizedBox(
                  height: 10.0,
                ),
                FlatButton.icon(
                  onPressed: () {},
                  icon: Icon(Icons.question_answer),
                  label: Text("A+B"),
                  color: Colors.tealAccent,
                  shape: RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(13.0),
                  ),
                ),
                SizedBox(
                  height: 10,
                ),
                InkWell(
                  onTap: () {
                    print("Tapped");
                  },
                  onDoubleTap: () {
                    print("double tapped");
                  },
                  onLongPress: () {
                    print("Long Pressed");
                  },
                  child: Container(
                    height: 50,
                    width: 100,
                    child: Text("InkWell"),
                    color: Colors.tealAccent,
                  ),
                ),
                SizedBox(height: 10.0,),
                GestureDetector(
                  onDoubleTap: () => ("Double Tapped"),
                  onHorizontalDragDown:(values) => print(values),
                  onVerticalDragEnd:(values1) => print(values1),
                    child: Container(
                    height: 50,width: 50,
                    color: Colors.tealAccent,
                    child: Text("Gesture"),
                  ),
                )
              ],
            ),
          )),
    );
  }
}