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。

要在按钮中使用任何形状，请确保执行button小部件内的所有代码:

 **shape: RoundedRectangleBorder(
        borderRadius: new BorderRadius.circular(18.0),
        side: BorderSide(color: Colors.red) ),**

如果你想让它变成正方形，使用BorderRadius.circular(0.0)，它会自动把它变成正方形。

按钮是这样的:

下面是给出UI屏幕的所有源代码:

 Scaffold(
    backgroundColor: Color(0xFF8E44AD),
    body: new Center(
      child: Column(
        children: <Widget>[
          Container(
            margin: EdgeInsets.fromLTRB(90, 10, 20, 0),
            padding: new EdgeInsets.only(top: 92.0),
            child: Text(
              "Currency Converter",
              style: TextStyle(
                fontSize: 48,
                fontWeight: FontWeight.bold,
                color: Colors.white,
              ),
            ),
          ),
          Container(
            margin: EdgeInsets.only(),
            padding: EdgeInsets.all(25),
            child: TextFormField(
              decoration: new InputDecoration(
                filled: true,
                fillColor: Colors.white,
                labelText: "Amount",
                border: OutlineInputBorder(
                  borderRadius: BorderRadius.circular(10),
                ),
              ),
            ),
          ),
          Container(
            padding: EdgeInsets.all(25),
            child: TextFormField(
              decoration: new InputDecoration(
                filled: true,
                fillColor: Colors.white,
                labelText: "From",
                border: OutlineInputBorder(
                  borderRadius: BorderRadius.circular(10),
                ),
              ),
            ),
          ),
          Container(
            padding: EdgeInsets.all(25),
            child: TextFormField(
              decoration: new InputDecoration(
                  filled: true,
                  fillColor: Colors.white,
                  labelText: "To",
                  border: OutlineInputBorder(
                    borderRadius: BorderRadius.circular(10),
                  )),
            ),
          ),
          SizedBox(height: 20.0),
          MaterialButton(
            height: 58,
            minWidth: 340,
            shape: RoundedRectangleBorder(
                borderRadius: new BorderRadius.circular(12)),
            onPressed: () {},
            child: Text(
              "CONVERT",
              style: TextStyle(
                fontSize: 24,
                color: Colors.black,
              ),
            ),
            color: Color(0xFFF7CA18),
          ),
        ],
      ),
    ),
  ),
);

如果你使用材质应用程序作为你的主小部件，你总是可以使用材质按钮。

Padding(
  padding: EdgeInsets.symmetric(vertical: 16.0),
  child: Material(
    borderRadius: BorderRadius.circular(30.0),//Set this up for rounding corners.
    shadowColor: Colors.lightBlueAccent.shade100,
    child: MaterialButton(
      minWidth: 200.0,
      height: 42.0,
      onPressed: (){//Actions here//},
      color: Colors.lightBlueAccent,
      child: Text('Log in', style: TextStyle(color: Colors.white),),
    ),
  ),
)

试试这个:

SizedBox(
  height: 40.0,
  child: MaterialButton(
    child: Text("Button"),
    color: Colors.blue,
    disabledColor: Colors.blue,
    shape: RoundedRectangleBorder(
      borderRadius: BorderRadius.all(
        Radius.circular(10.0), // Change your border radius here
      ),
    ),
    onPressed: () {},
  ),
),

你也可以使用ButtonTheme():

下面是示例代码

ButtonTheme(
    minWidth: 200.0,
    shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(18.0),
        side: BorderSide(color: Colors.green)),
    child: RaisedButton(
        elevation: 5.0,
        hoverColor: Colors.green,
        color: Colors.amber,
        child: Text(
            "Place Order",
            style: TextStyle(
                     color: Colors.white, fontWeight: FontWeight.bold),
        ),
        onPressed: () {},
    ),
),

addButton() {
return Row(
  mainAxisAlignment: MainAxisAlignment.center,
  children: <Widget>[
    Padding(
      padding: const EdgeInsets.symmetric(vertical: 10.0),
      child: SizedBox(
        height: 45,
        width: 200,
        child: ElevatedButton.icon(
          onPressed: () async {},
          style: ButtonStyle(
            shape: MaterialStateProperty.all<RoundedRectangleBorder>(
                RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(30.0),
                  )),
            elevation: MaterialStateProperty.all(1),
            backgroundColor: MaterialStateProperty.all(Colors.blue),
          ),
          icon: Icon(Icons.add, size: 18),
          label: Text("Add question"),
        ),
      ),
    ),
  ],
);

}