我试图从单击按钮时传递一个值,我想要在代码中将值从Button窗口小部件传递给另一个名为pdfNo的页面变量。这是我的代码:
FlatButton(
padding: EdgeInsets.fromLTRB(2, 5, 5, 5),
child: ListTile(
leading: Icon(Icons.book, color: Color(0xFFEB3549)),
title: Text('Book5'),
),
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => PDFPage() ));
print('Pressed 6');
},
),`
这是第一页上的按钮,在按下时,我想将一个值传递给一个子函数,因此我创建了一个变量,但无法弄清楚下一步如何处理:
var pdfNo = 2;
bool _isLoading = true;
PDFDocument document;
@override
void initState() {
super.initState();
changePDF(pdfNo);
loadDocument();
}
changePDF(value) async {
setState(() => _isLoading = true);
if (value == 1) {
document = await PDFDocument.fromAsset('assets/sample2.pdf');
} else if (value == 2) {
document = await PDFDocument.fromURL(
"http://conorlastowka.com/book/CitationNeededBook-Sample.pdf");
} else {
document = await PDFDocument.fromAsset('assets/sample.pdf');
}
setState(() => _isLoading = false);
}
因此,我想将int从第1页的Staleful Class的按钮传递给第二页的有状态的类,以更改PDF(此处)。
请帮帮我。 PS Flutter的新手,Dart
您可以创建to
自变量...
这样的东西
class LoginWidgetArguments {
final String username;
LoginWidgetArguments(
{this.username});
}
class LoginWidget extends StatefulWidget {
@override
State<StatefulWidget> createState() => _LoginWidgetState();
}
class _LoginWidgetState extends State<LoginWidget>{
LoginWidgetArguments args;
@override
void initState() {
//Get context
// I do this because sometimes it doesn't get the context without the FutureDelay... This workaround I used with the first flutter versions, maybe now its not needed
Future.delayed(Duration.zero, () {
args = ModalRoute.of(context).settings.arguments;
if (args != null) {
print(args.username)
}
});
}
....
}
和导航
Navigator.pushNamed(context, LoginPage.routeName,
arguments: LoginWidgetArguments(
user: "[email protected]");