我有点困惑，因为我真的不知道为什么 Alloy Analyzer 没有找到这个简单问题的解决方案。我只想为每个人提供一个唯一的 ID...
abstract sig Person {
id: Int
} {id > 0}
sig Candidato extends Person {
votiRicevuti: Int
}
sig Elettore extends Person {
votiDati: set Voto
}
sig Voto {
votante: Elettore,
votato: Candidato
}
fact {
#Candidato > 0
#Elettore > 0
}
fact {
all p1, p2: Person |
p1.id != p2.id
}
run {} for 4 but 4 Elettore, 4 Candidato
我正在努力寻找一种解决方案来管理容器边框的颜色，而无需每次都对它们进行硬编码。
我想在 ThemeData 中为白天模式和夜间模式的边框定义自定义颜色，但我找不到正确的属性。目前 Dart 为边框选择的颜色是深色。
只是为了清楚起见...我想写一些这样的东西：
border: Border.all(
width: width * 0.002,
),
未指定颜色。
我遇到了一个关于 Provider 包的烦人问题。我想实现夜间模式开关。我试过在单独的屏幕上使用 Provider，而且可以正常工作，但显然在我需要它的地方，它却不行 :)
我的主题课
class MyTheme {
static ThemeData lightTheme = ThemeData(
//something very nice
);
static ThemeData nightTheme = ThemeData(
//something very nice
);
}
我的根页面
class MyApp extends StatelessWidget {
const MyApp({super.key});
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return ChangeNotifierProvider(
create: (context) => ThemeProvider(),
builder: (context, child) {
final provider = Provider.of<ThemeProvider>(context);
return MaterialApp(
debugShowCheckedModeBanner: true,
initialRoute: LoginScreen.id,
onGenerateRoute: RouteGenerator.generateRoute,
theme: provider.themeData,
home: const HomeScreen(),
);
});
}
}
我的主页（其中有用于更改模式的按钮）
class _HomeScreenState extends State<HomeScreen> {
final GlobalKey<ScaffoldState> _globalKey = GlobalKey<ScaffoldState>();
@override
Widget build(BuildContext context) {
double height = MediaQuery.of(context).size.height;
double width = MediaQuery.of(context).size.width;
return Scaffold(
key: _globalKey,
drawer: MyAppDrawer(
height: height,
width: width,
colore: MyTheme.coloreTesto,
),
body:
MyAppDrawer 小部件
class MyAppDrawer extends StatelessWidget {
const MyAppDrawer(
{super.key,
required this.height,
required this.width,
required this.colore});
final double height;
final double width;
final Color colore;
@override
Widget build(BuildContext context) {
final provider = Provider.of<ThemeProvider>(context);
return Drawer(
width: width * 0.7,
child: Container(
padding: EdgeInsets.only(
top: height * 0.1, left: width * 0.08, right: width * 0.08),
color: Colors.white,
child: Column(
mainAxisAlignment: MainAxisAlignment.start,
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Container(
margin: EdgeInsets.symmetric(vertical: height * 0.01),
child: Row(
children: [
Container(
child: ElevatedButton(
style: ButtonStyle(
backgroundColor:
MaterialStateProperty.all(Colors.white),
elevation: MaterialStateProperty.all(0.0),
padding: MaterialStateProperty.all(EdgeInsets.zero),
shape:
MaterialStateProperty.all<RoundedRectangleBorder>(
RoundedRectangleBorder(
borderRadius: BorderRadius.all(
Radius.circular(width * 0.015))))),
onPressed: () {
debugPrint('nightModePremuto');
provider.toggleTheme;
},
child: Icon(
size: width * 0.06,
Icons.dark_mode,
color: colore,
),
),
),
Text(
'Night Mode',
style: TextStyle(
color: colore,
fontSize: width * 0.04,
),
),
],
),
),
提供者类
class ThemeProvider extends ChangeNotifier {
ThemeData _themeData = MyTheme.lightTheme;
ThemeData get themeData => _themeData;
void toggleTheme() {
debugPrint('Siamo entrati nel toggle');
final isLight = _themeData == MyTheme.lightTheme;
isLight ? _themeData = MyTheme.nightTheme : _themeData = MyTheme.lightTheme;
notifyListeners();
}
}
我试过调试模式，发现它甚至没有进入 toggleTheme() 方法（Provider 类中的方法）。我真的不知道为什么。
我有这个自定义小部件
class MyEventCard extends StatelessWidget {
const MyEventCard({
super.key,
required this.height,
required this.width,
required this.coloreChiaroSfondo,
required this.coloreScuro,
required this.data,
required this.image,
required this.sottotitolo,
required this.titolo,
});
final double height;
final double width;
final Color coloreChiaroSfondo;
final Color coloreScuro;
final String image;
final String data;
final String titolo;
final String sottotitolo;
@override
Widget build(BuildContext context) {
return GestureDetector(
onTap: () {},
child: Container(
margin: EdgeInsets.symmetric(vertical: height * 0.005),
padding: EdgeInsets.symmetric(
horizontal: width * 0.02, vertical: width * 0.02),
decoration: BoxDecoration(
borderRadius: BorderRadius.all(Radius.circular(width * 0.02)),
color: coloreChiaroSfondo,
border: Border.all(
color: coloreScuro, // Colore del bordo
width: width * 0.001, // Larghezza del bordo
),
),
child: Row(
children: [
Container(
constraints: BoxConstraints(
maxHeight: height * 0.4, maxWidth: width * 0.25),
child: ClipRRect(
borderRadius: BorderRadius.all(Radius.circular(width * 0.01)),
child: Image.asset(
image,
fit: BoxFit.cover,
),
),
),
Padding(
padding: EdgeInsets.symmetric(horizontal: width * 0.04),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
data,
style:
TextStyle(color: coloreScuro, fontSize: width * 0.035),
),
Text(
titolo,
style: TextStyle(
color: coloreScuro,
fontWeight: FontWeight.bold,
fontSize: width * 0.035,
),
),
Text(
sottotitolo,
style: TextStyle(
color: coloreScuro,
fontWeight: FontWeight.bold,
fontSize: width * 0.035,
),
),
],
),
),
Expanded(
child: SizedBox(
width: width * 0.1,
),
),
IconButton(
onPressed: () {
debugPrint('puntini premuti');
},
icon: Icon(
Icons.favorite_outline,
size: width * 0.06,
color: coloreScuro,
))
],
),
),
);
}
}
当文本小部件中的某些字符串太长时，就会导致溢出：
我希望得到这样的结果：
因此，如果行中没有足够的空间，我希望文本小部件内的文本自动转到下一行。
您知道如何解决这个问题吗？我已经尝试将文本小部件放入灵活或扩展小部件中，但没有成功。