Question

我创建了以下的custome小部件：

df1.union(df2).groupBy("key").pivot("date").agg(max("val")).show

+---+----------+----------+----------+                                          
|key|2016-04-16|2017-04-16|2018-04-16|
+---+----------+----------+----------+
|  1|        20|        10|       100|
|  2|      null|      null|       200|
+---+----------+----------+----------+

}

以下是我创建MainButtonWidget类型的对象的方法：

class MainButtonWidget extends StatelessWidget{
  String _text = "";
  TextTheme _textTheme = new TextTheme();
  IconData _icon = null;
  VoidCallback _onPressed;

  MainButtonWidget(String text, TextTheme textTheme, IconData icon, VoidCallback onPressed){
    _text = text;
    _textTheme = textTheme;
    _icon = icon;
    _onPressed = onPressed;
  }

  void setText(String text){
    _text = text;
  }

@override
Widget build(BuildContext context) {
  return new Container(
    child: new RaisedButton(
      padding: const EdgeInsets.fromLTRB(
          Dimens.edgeMainButtonLRB, Dimens.edgeMainButtonT,
          Dimens.edgeMainButtonLRB, Dimens.edgeMainButtonLRB),
      shape: new CircleBorder(side: new BorderSide(
          color: ColorRes.whiteTranslucent2,
          width: Dimens.widthSmallButtonHome)),
      onPressed: (){
        debugPrint("mainButtonWidget before _onPressed");
        _onPressed;
        debugPrint("mainButtonWidget after _onPressed");
        },
      color: Colors.transparent,
      child: new Column(
        children: <Widget>[
          new Icon(
            _icon,
            color: Colors.white,
          ),
          new Text(_text,
            style: _textTheme.button.copyWith(
              color: Colors.white,
            ),)
        ],
      ),
    ),
  );
}

按下按钮时，似乎没有执行VoidCallback的内容。

在日志中显示以下消息： I / flutter（21436）：_onPressed之前的mainButtonWidget I / flutter（21436）：_onPressed之后的mainButtonWidget

我希望看到'mapMainBtn - ＆gt; onPressed称为'在上述消息之间。

Answer 1

要求将其称为()

_onPressed();

Answer 2

调用

_onPressed（）。
请参阅下面的代码：

`onPressed: (){
 debugPrint("mainButtonWidget before _onPressed");
    _onPressed;
    debugPrint("mainButtonWidget after _onPressed");
}`

Flutter - VoidCallback内容未执行

2 个答案: