Flutter：自定义小部件不显示元素

Question

我创建了自定义小部件 (cardChild)，但它没有显示任何元素

class ReuseableCard extends StatelessWidget {
  ReuseableCard({required this.colour, required this.cardChild});
  Color colour;
  final Widget cardChild;

应用程序中未显示图标和文本

                Expanded(
                  child: ReuseableCard(
                    colour: activeCardColour,
                    cardChild: Column(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: [
                        Icon(
                          FontAwesomeIcons.mars,
                          size: 80.0,
                        ),
                        Text(
                          'Male',
                          style: TextStyle(
                              fontSize: 18.0, color: Color(0xFF8D8E98)),
                        )],
                    ),
                  ),),

flutter没有报错并请说明为什么widget需要“required”才能构建。

Answer 1

class ReuseableCard extends StatelessWidget {
  ReuseableCard({required this.colour, required this.cardChild});
  Color colour;
  final Widget cardChild;

  @override
  Widget build(BuildContext context) {
    return Container(
      child: cardChild,    //Here 
      margin: const EdgeInsets.all(15.0),
      decoration: BoxDecoration(
        borderRadius: BorderRadius.circular(10.0),
        color: colour,
      ),
    );}
}

我们需要在Container中添加cardChild。

Answer 2

希望这能解决您的问题..

class SecondRoute extends StatelessWidget {
  const SecondRoute({Key? key, required this.argumentWidget}) : super(key: key);
  
  final Widget argumentWidget;

  @override
  Widget build(BuildContext context) {
    
    return Scaffold(
      body: Column(
        children: [
          argumentWidget,/// this widget is come from FirstRoute screen as you can see we are on second route screen
          customMyWidget(stringData: 'myNameIsFlutterDev'),//this is from your class 
        ],
      ),
    );
  }
  
  // the below widget is your customWidget inside the class
  
  Widget customMyWidget({required String stringData}){
    return Text(stringData);
  }
}

Flutter：自定义小部件不显示元素

Flutter: Custom Widget not showing elements

android

flutter

custom-widgets