创建圆角按钮的不同方法如下:

用ElevatedButton. stylefrom

ElevatedButton(
          style: ElevatedButton.styleFrom(
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(30.0),
            ),
          ),
          onPressed: () {},
          child:
              Text("Buy now".toUpperCase(), style: TextStyle(fontSize: 14)),
        ),

用ButtonStyle提升按钮

ElevatedButton(
          style: ButtonStyle(
              shape: MaterialStateProperty.all<RoundedRectangleBorder>(
                  RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(50.0),
          ))),
          onPressed: () {},
          child: Text("Submit".toUpperCase()),
        ),

圆形按钮的实际演示可以在下面的Dartpad链接中找到:

圆形按钮演示例子在达特pad

你可以使用这个样式为你的elevatedButton使它成为圆形

style: ButtonStyle(
              elevation: MaterialStateProperty.all(8.0),
              backgroundColor:
                  MaterialStateProperty.all(Constants().orangeColor),
              textStyle: MaterialStateProperty.all(
                TextStyle(
                  fontSize: 16.0,
                ),
              ),
              shape: MaterialStateProperty.all<CircleBorder>(
                CircleBorder(),
              ),
              shadowColor: MaterialStateProperty.all(Constants().orangeColor),
            ),

您可以使用下面的代码创建一个渐变颜色的圆形按钮。

 Container(
          width: 130.0,
          height: 43.0,
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(30.0),
            gradient: LinearGradient(
              // Where the linear gradient begins and ends
              begin: Alignment.topRight,
              end: Alignment.bottomLeft,
              // Add one stop for each color. Stops should increase from 0 to 1
              stops: [0.1, 0.9],
              colors: [
                // Colors are easy thanks to Flutter's Colors class.
                Color(0xff1d83ab),
                Color(0xff0cbab8),
              ],
            ),
          ),
          child: FlatButton(
            child: Text(
              'Sign In',
              style: TextStyle(
                fontSize: 16.0,
                fontFamily: 'Righteous',
                fontWeight: FontWeight.w600,
              ),
            ),
            textColor: Colors.white,
            color: Colors.transparent,
            shape:
                RoundedRectangleBorder(borderRadius: BorderRadius.circular(30.0)),
            onPressed: () {

            },
          ),
        );

更新

由于左侧按钮现在已弃用，请使用右侧按钮。

Deprecated    -->   Recommended

RaisedButton  -->   ElevatedButton
OutlineButton -->   OutlinedButton
FlatButton    -->   TextButton

ElevatedButton

Using StadiumBorder ElevatedButton( onPressed: () {}, child: Text('Button'), style: ElevatedButton.styleFrom(shape: StadiumBorder()), ) Using RoundedRectangleBorder ElevatedButton( onPressed: () {}, child: Text('Button'), style: ElevatedButton.styleFrom( shape: RoundedRectangleBorder( borderRadius: BorderRadius.circular(12), // <-- Radius ), ), ) Using CircleBorder ElevatedButton( onPressed: () {}, child: Text('Button'), style: ElevatedButton.styleFrom( shape: CircleBorder(), padding: EdgeInsets.all(24), ), ) Using BeveledRectangleBorder ElevatedButton( onPressed: () {}, child: Text('Button'), style: ElevatedButton.styleFrom( shape: BeveledRectangleBorder( borderRadius: BorderRadius.circular(12) ), ), )

OutlinedButton

Using StadiumBorder OutlinedButton( onPressed: () {}, child: Text('Button'), style: OutlinedButton.styleFrom( shape: StadiumBorder(), ), ) Using RoundedRectangleBorder OutlinedButton( onPressed: () {}, child: Text('Button'), style: OutlinedButton.styleFrom( shape: RoundedRectangleBorder( borderRadius: BorderRadius.circular(12), ), ), ) Using CircleBorder: OutlinedButton( onPressed: () {}, child: Text('Button'), style: OutlinedButton.styleFrom( shape: CircleBorder(), padding: EdgeInsets.all(24), ), ) Using BeveledRectangleBorder OutlinedButton( onPressed: () {}, child: Text('Button'), style: OutlinedButton.styleFrom( shape: BeveledRectangleBorder( borderRadius: BorderRadius.circular(12), ), ), )

TextButton

TextButton也类似于ElevatedButton和OutlinedButton，但是，你只能看到按钮按下的形状。

RaisedButton(
          child: Text("Button"),
          onPressed: (){},
          shape: RoundedRectangleBorder(borderRadius: new BorderRadius.circular(30.0),
          side: BorderSide(color: Colors.red))
        )

还有另一种方法来做到这一点-只是使用FloatingActionButton适当的圆形按钮。

Scaffold(
      appBar: AppBar(
        title: const Text('Floating Action Button'),
      ),
      body: const Center(child: Text('Press the button below!')),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          // Add your onPressed code here!
        },
        backgroundColor: Colors.green,
        child: const Icon(Icons.navigation),
      ),
    )