填充内部扩展

Question

我需要使用 Flutter 创建一个全屏表格。由于我无法使用Table/DataTable我正在尝试使用Flex/ Expanded。

Everithing 按预期工作，但我不能设置样式Expanded's child，因此例如我似乎无法设置填充。

到目前为止，这是我的代码。

main.dart：

import 'package:flutter/material.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      home: Calendar2(),
    );
  }
}

calendar2.dart：

import 'package:flutter/material.dart';

class Calendar2 extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _Calendar2State();

}

class _Calendar2State extends State<Calendar2> {

  @override
  Widget build(BuildContext context) {
    List<CalendarRow> tableRows = buildTable();
    print(tableRows);

    return Scaffold(
      body: Flex(
        direction: Axis.vertical,
        children: tableRows,
      )
    );
  }

  List<CalendarRow> buildTable() {
    List<CalendarRow> rows = <CalendarRow>[];

    for(int i=0; i<4; i++) {
      List<Widget> children = [];
      for(int j=0; j<7; j++) {
        children.add(
          CalendarCell(
            child: Text((i * 7 + j + 1).toString())
          )
        );
      }
      rows.add(
        CalendarRow(
          children: children
        )
      );
    }
    return rows;
  }

}

class CalendarCell extends StatelessWidget {
  Widget child;

  CalendarCell({this.child}) {}

  @override
  Widget build(BuildContext context) {
    return Expanded (
      flex: 1,
      child: Padding(
        child: child,
        padding: EdgeInsets.all(0.0), // this doesn't work for top and bottom
      )
    );
  }
}

class CalendarRow extends StatelessWidget {
  List<Widget> children = <Widget>[];

  CalendarRow({this.children}) {}

  @override
  Widget build(BuildContext context) {
    return Expanded(
      flex: 1,
      child: Flex(
          direction: Axis.horizontal,
          children: children
      )
    );
  }
}

我怎样才能child在里面Expanded穿出风格？

Answer 1

这就是在 flutter 中使用 Expanded 小部件完成填充的方式

    class DicePage extends StatelessWidget {
    @override
     Widget build(BuildContext context) {
      return Center(
       child: Row(
        children: <Widget>[
         Expanded(
          child: Padding(
           padding: const EdgeInsets.all(16.0),
          child: Image.asset('images/dice1.png'),
        ),
      ),
      Expanded(
        child: Padding(
          padding: const EdgeInsets.all(16.0),
          child: Image.asset('images/dice1.png'),
        ),
      ),
    ],
  ),
);

Answer 2

您的 CalendarCell 没有垂直内边距。在 CalendarRow 中，您正在使用 Expanded，因此所有行都在屏幕上展开。使用灵活代替

class Calendar2 extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _Calendar2State();

}

class _Calendar2State extends State<Calendar2> {

  @override
  Widget build(BuildContext context) {
    List<CalendarRow> tableRows = buildTable();
    print(tableRows);

    return Scaffold(
        body: Flex(
          mainAxisAlignment: MainAxisAlignment.center,
          direction: Axis.vertical,
          children: tableRows,
        )
    );
  }

  List<CalendarRow> buildTable() {
    List<CalendarRow> rows = <CalendarRow>[];

    for(int i=0; i<4; i++) {
      List<Widget> children = [];
      for(int j=0; j<7; j++) {
        children.add(
            CalendarCell(
                child: Text((i * 7 + j + 1).toString())
            )
        );
      }
      rows.add(
          CalendarRow(
              children: children
          )
      );
    }
    return rows;
  }

}

class CalendarCell extends StatelessWidget {
  final Widget child;

  CalendarCell({this.child});

  @override
  Widget build(BuildContext context) {
    return Expanded (
        flex: 1,
        child: Padding(
          child: child,
          padding: EdgeInsets.all(0.0), // this doesn't work for top and bottom
        )
    );
  }
}

class CalendarRow extends StatelessWidget {
  final List<Widget> children;

  CalendarRow({this.children = const <Widget>[]});

  @override
  Widget build(BuildContext context) {
    return Flexible(
        child: Flex(
            direction: Axis.horizontal,
            children: children
        )
    );
  }
}