我有这个委托功能：
Widget SignupPage() {
return new Scaffold(body: Container(
height: MediaQuery.of(context).size.height,
decoration: BoxDecoration(
color: Colors.white,
image: DecorationImage(
colorFilter: new ColorFilter.mode(
Colors.black.withOpacity(0.05), BlendMode.dstATop),
image: AssetImage('assets/images/mountains.jpg'),
fit: BoxFit.cover,
),
),
child: new Column(
children: <Widget>[
Container(
padding: EdgeInsets.all(100.0),
child: Center(
child: Icon(
Icons.headset_mic,
color: Colors.redAccent,
size: 50.0,
),
),
),
new Row(
children: <Widget>[
new Expanded(
child: new Padding(
padding: const EdgeInsets.only(left: 40.0),
child: new Text(
"EMAIL",
style: TextStyle(
fontWeight: FontWeight.bold,
color: Colors.redAccent,
fontSize: 15.0,
),
),
),
),
],
),
new Container(
width: MediaQuery.of(context).size.width,
margin: const EdgeInsets.only(left: 40.0, right: 40.0, top: 10.0),
alignment: Alignment.center,
decoration: BoxDecoration(
border: Border(
bottom: BorderSide(
color: Colors.redAccent,
width: 0.5,
style: BorderStyle.solid),
),
),
padding: const EdgeInsets.only(left: 0.0, right: 10.0),
child: new Row(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
new Expanded(
child: TextField(
obscureText: true,
textAlign: TextAlign.left,
decoration: InputDecoration(
border: InputBorder.none,
hintText: 'PLEASE ENTER YOUR EMAIL',
hintStyle: TextStyle(color: Colors.grey),
),
),
),
],
),
),
Divider(
height: 24.0,
),
new Row(
children: <Widget>[
new Expanded(
child: new Padding(
padding: const EdgeInsets.only(left: 40.0),
child: new Text(
"PASSWORD",
style: TextStyle(
fontWeight: FontWeight.bold,
color: Colors.redAccent,
fontSize: 15.0,
),
),
),
),
],
),
new Container(
width: MediaQuery.of(context).size.width,
margin: const EdgeInsets.only(left: 40.0, right: 40.0, top: 10.0),
alignment: Alignment.center,
decoration: BoxDecoration(
border: Border(
bottom: BorderSide(
color: Colors.redAccent,
width: 0.5,
style: BorderStyle.solid),
),
),
padding: const EdgeInsets.only(left: 0.0, right: 10.0),
child: new Row(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
new Expanded(
child: TextField(
obscureText: true,
textAlign: TextAlign.left,
decoration: InputDecoration(
border: InputBorder.none,
hintText: '*********',
hintStyle: TextStyle(color: Colors.grey),
),
),
),
],
),
),
Divider(
height: 24.0,
),
new Row(
children: <Widget>[
new Expanded(
child: new Padding(
padding: const EdgeInsets.only(left: 40.0),
child: new Text(
"CONFIRM PASSWORD",
style: TextStyle(
fontWeight: FontWeight.bold,
color: Colors.redAccent,
fontSize: 15.0,
),
),
),
),
],
),
new Container(
width: MediaQuery.of(context).size.width,
margin: const EdgeInsets.only(left: 40.0, right: 40.0, top: 10.0),
alignment: Alignment.center,
decoration: BoxDecoration(
border: Border(
bottom: BorderSide(
color: Colors.redAccent,
width: 0.5,
style: BorderStyle.solid),
),
),
padding: const EdgeInsets.only(left: 0.0, right: 10.0),
child: new Row(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
new Expanded(
child: TextField(
obscureText: true,
textAlign: TextAlign.left,
decoration: InputDecoration(
border: InputBorder.none,
hintText: '*********',
hintStyle: TextStyle(color: Colors.grey),
),
),
),
],
),
),
Divider(
height: 24.0,
),
new Row(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
Padding(
padding: const EdgeInsets.only(right: 20.0),
child: new FlatButton(
child: new Text(
"Already have an account?",
style: TextStyle(
fontWeight: FontWeight.bold,
color: Colors.redAccent,
fontSize: 15.0,
),
textAlign: TextAlign.end,
),
onPressed: () => {},
),
),
],
),
new Container(
width: MediaQuery.of(context).size.width,
margin: const EdgeInsets.only(left: 30.0, right: 30.0, top: 50.0),
alignment: Alignment.center,
child: new Row(
children: <Widget>[
new Expanded(
child: new FlatButton(
shape: new RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(30.0),
),
color: Colors.redAccent,
onPressed: () => authHandler.handleSignInEmail(emailController.text, passwordController.text)
.then((FirebaseUser user) {
Navigator.push(context, new MaterialPageRoute(builder: (context) => HomePage()));
}).catchError((e) => print(e)),
child: new Container(
padding: const EdgeInsets.symmetric(
vertical: 20.0,
horizontal: 20.0,
),
child: new Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Expanded(
child: Text(
"SIGN UP",
textAlign: TextAlign.center,
style: TextStyle(
color: Colors.white,
fontWeight: FontWeight.bold),
),
),
],
),
),
),
),
],
),
),
],
),
));
}
这是我要尝试的方法：
extension AppDelegate: SirenDelegate {
func sirenNetworkCallDidReturnWithNewVersionInformation(lookupModel: SirenLookupModel) {
// ^ need to convert the results into a string that can be used elsewhere
}
}
（在updateMessage：变量下）
siren.alertMessaging = SirenAlertMessaging(updateTitle: "Plese update!",
updateMessage: SirenDelegate.sirenNetworkCallDidReturnWithNewVersionInformation.(lookupModel: <#T##SirenDelegate#>),
updateButtonMessage: "Update Now",
nextTimeButtonMessage: "Remind Me",
skipVersionButtonMessage: "Skip")
但是它给我错误（“。”之后的预期成员名称），但是没有其他名称可以使用...
该委托函数以这种方式返回数据：
updateMessage: SirenDelegate.sirenNetworkCallDidReturnWithNewVersionInformation.(lookupModel: <#T##SirenDelegate#>)
我正在尝试将有关“这是一个错误修复更新”的部分显示为字符串中的消息。
答案 0 :(得分：0)
不要自己调用委托方法。委托方法由目标类调用。
委托方法返回您在lookupModel参数中需要的信息。调用时显示警报。
我不确定SirenLookupModel实际包含的内容，因此lookupModel.results[0].releaseNotes可能是错误的，但是它给您留下了工作流程的印象。
func sirenNetworkCallDidReturnWithNewVersionInformation(lookupModel: SirenLookupModel) {
siren.alertMessaging = SirenAlertMessaging(updateTitle: "Please update!",
updateMessage: lookupModel.results[0].releaseNotes,
updateButtonMessage: "Update Now",
nextTimeButtonMessage: "Remind Me",
skipVersionButtonMessage: "Skip")
}
答案 1 :(得分：0)
这是错误的方法，因为您不应该自己调用委托函数，这将由您自己完成，相反，在委托方法中，您应该注意参数中的结果，例如< / p>
var updateMessage: String?
func sirenNetworkCallDidReturnWithNewVersionInformation(lookupModel: SirenLookupModel) {
self.updateMessage = lookupModel.results[0].releaseNotes
}
，然后在您的警报中使用updateMessage属性