切换按钮颤动不起作用

Question

我仍然是 flutter 的初学者，我正在尝试制作一个小应用程序以允许用户将单位从 SI 转换为 IP 单位...我使用 ToggleButton，尝试一次ToggleButton 切换页面底部的小文本必须更改，但没有任何反应，任何人都可以帮助我做错了什么......代码是

class ToggleButtonPage extends StatefulWidget {
  const ToggleButtonPage({Key key}) : super(key: key);

  @override
  _ToggleButtonPageState createState() => _ToggleButtonPageState();
}

class _ToggleButtonPageState extends State<ToggleButtonPage> {
  bool siUnits;
  String siUnitsText;
  String showText;

  List<bool> isSelected2 = [true, false];

  String textShow(String siUnitsText) {
    if (siUnitsText == 'true') {
      showText = 'ooooooo';
    } else {
      showText = 'xxx';
      print('xxx');
    }
    return showText;
  }

  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Container(
            margin: EdgeInsets.only(top: 50.0),
            child: ToggleButtons(
              fillColor: Colors.lightGreen,
              borderWidth: 2,
              borderColor: Colors.blueGrey,
              selectedBorderColor: Colors.black,
              borderRadius: BorderRadius.circular(10),
              children: [
                Text(
                  'SI',
                  style: TextStyle(
                    fontSize: 15,
                  ),
                ),
                Text(
                  'IP',
                  style: TextStyle(
                    fontSize: 15,
                  ),
                ),
              ],
              onPressed: (int newIndex) {
                setState(() {
                  switch (newIndex) {
                    case 0:
                      siUnitsText = 'true';
                      break;
                    case 1:
                      siUnitsText = 'false';
                      break;
                  }

                  for (int index = 0; index < isSelected2.length; index++) {
                    if (index == newIndex) {
                      isSelected2[index] = true;
                    } else {
                      isSelected2[index] = false;
                    }
                  }
                });
                print(siUnitsText);
              },
              isSelected: isSelected2,
            ),
          ),
          Text('Value is equal to  $showText'),
        ],
      ),
    );
  }
}

这里还有一张布局照片

Answer 1

showText 变量最初为空。在 Text 小部件中显示它之前，您没有设置 showText。如果textShow方法用于设置showText变量，则在setState.

中调用textShow方法

切换按钮颤动不起作用

Toggle Button flutter not functioning

togglebutton

flutter