Flutter中如何创建按钮

Question

How do you create these buttons this way? Needed for my academic work. Please help me.

Answer 1

Here is how you make an ElevatedButton :

ElevatedButton(
  child: Text('Press me!'),
  onPressed: () {
    print('Hello');
  },
),

You can also make other kinds of buttons. See the documentation for details.

• TextButton
• OutlinedButton

Answer 2

Welcome to SOF & Flutter.

For every question, there is an answer, please check the code below, the complete source code is included:)

I used CustomPaint to draw the rounded corner triangle, using this handy website: https://fluttershapemaker.com/

import 'package:flutter/material.dart';
import 'dart:ui' as ui;

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
        // This makes the visual density adapt to the platform that you run
        // the app on. For desktop platforms, the controls will be smaller and
        // closer together (more dense) than on mobile platforms.
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  var WIDTH = 192.0;
  var HEIGHT = 48.0;

  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      backgroundColor: Color(0xFF4B0A2B),
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug painting" (press "p" in the console, choose the
          // "Toggle Debug Paint" action from the Flutter Inspector in Android
          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
          // to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Container(width: WIDTH, height: HEIGHT, child: customButtonWidget()),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }

  Widget customButtonWidget() {
    List<Color> _colors = [Colors.deepOrange, Colors.yellow];
    List<double> _stops = [0.0, 0.7];
    return Stack(
      children: [
        // round box
        Padding(
          padding: EdgeInsetsDirectional.fromSTEB(WIDTH*0.19, 0, 0, 0),
          child: Container(
              decoration: new BoxDecoration(
                  gradient: LinearGradient(
                    colors: _colors,
                    stops: _stops,
                  ),
                  borderRadius: new BorderRadius.only(
                    topLeft: const Radius.circular(0.0),
                    topRight: const Radius.circular(40.0),
                    bottomRight: const Radius.circular(40.0),
                    bottomLeft: const Radius.circular(0.0),
                  )),
              child: new Center(
                child: new Text("View",textScaleFactor: 2.0,),
              )),
        ),
        CustomPaint(
          size: Size(64, HEIGHT), //You can Replace [WIDTH] with your desired width for Custom Paint and height will be calculated automatically
          painter: RPSCustomPainter(),
        ),
      ],
    );
  }
}


class RPSCustomPainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {

    Path path_0 = Path();
    path_0.moveTo(size.width*0.6154700,size.height*0.9259259);
    path_0.cubicTo(size.width*0.5641500,size.height*1.024691,size.width*0.4358500,size.height*1.024691,size.width*0.3845300,size.height*0.9259259);
    path_0.lineTo(size.width*0.02368650,size.height*0.2314815);
    path_0.cubicTo(size.width*-0.02763350,size.height*0.1327159,size.width*0.03651650,size.height*0.009259167,size.width*0.1391565,size.height*0.009259185);
    path_0.lineTo(size.width*0.8608450,size.height*0.009259241);
    path_0.cubicTo(size.width*0.9634850,size.height*0.009259259,size.width*1.027635,size.height*0.1327161,size.width*0.9763150,size.height*0.2314815);
    path_0.lineTo(size.width*0.6154700,size.height*0.9259259);
    path_0.close();

    Paint paint_0_fill = Paint()..style=PaintingStyle.fill;
    paint_0_fill.shader = ui.Gradient.linear(Offset(size.width,size.height*0.5000000), Offset(size.width*0.1166667,size.height*0.5000000),
        [Color(0xffcccccc).withOpacity(1),Colors.white.withOpacity(1)], [0,1]);
    canvas.drawPath(path_0,paint_0_fill);
    Paint paint_0_stroke = Paint()..style=PaintingStyle.stroke;
    paint_0_stroke.shader = ui.Gradient.linear(Offset(size.width,size.height*0.5000000), Offset(size.width*0.1166667,size.height*0.5000000),
        [Color(0xffffff).withOpacity(1),Colors.white.withOpacity(0.9)], [0,1]);
    paint_0_stroke.strokeWidth=3;
    canvas.drawPath(path_0,paint_0_stroke);

  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) {
    return true;
  }
}

Answer 3

you can use ElevatedButton Widget

 Widget buttonElevated() { return ElevatedButton( child: Text("Elevated Button", style: TextStyle(fontSize: 30)) onPressed: onPress,//function ); }