谢谢您前面的回答。我正在尝试将GetTextField StatelessWidget中的TextField小部件中的“用户名，电子邮件，密码”传递给GetSignup StatelessWidget中的GestureDetector小部件中的打印功能。我尝试了两种方法，但是在填写字段并按下按钮后，均出现“用户名：null，用户电子邮件：null，用户密码：null”消息。可能有什么问题吗？
方法1：
class SignupScreen extends StatefulWidget {
static const id = "signup_screen";
@override
_SignupScreenState createState() => _SignupScreenState();
}
class _SignupScreenState extends State<SignupScreen> {
@override
Widget build(BuildContext context) {
return Scaffold(
body: CustomPaint(
painter: BackgroundSignup(),
child: Stack(
children: <Widget>[
Padding(
padding: EdgeInsets.symmetric(
horizontal: 35,
),
child: Column(
children: <Widget>[
GetHeader(),
GetTextField(),
GetSignup(),
GetButtonRow(),
],
),
),
GetBackButton(),
],
),
),
);
}
}
class GetTextField extends StatelessWidget {
String email;
String password;
String username;
@override
Widget build(BuildContext context) {
return Expanded(
flex: 4,
child: Column(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
SizedBox(
height: 15,
),
Directionality(
textDirection: TextDirection.rtl,
child: TextField(
onChanged: (value) {
username = value;
},
textAlign: TextAlign.start,
decoration: InputDecoration(
labelText: "الاسم كاملا",
labelStyle:
TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.white),
),
),
),
),
SizedBox(
height: 15,
),
Directionality(
textDirection: TextDirection.rtl,
child: TextField(
onChanged: (value) {
email = value;
},
textAlign: TextAlign.start,
decoration: InputDecoration(
labelText: "الإيميل",
labelStyle:
TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.white),
),
),
),
),
SizedBox(
height: 15,
),
Directionality(
textDirection: TextDirection.rtl,
child: TextField(
onChanged: (value) {
password = value;
},
obscureText: true,
textAlign: TextAlign.start,
decoration: InputDecoration(
labelText: "كلمة السر",
labelStyle:
TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.white),
),
),
),
),
SizedBox(
height: 25,
),
],
),
);
}
}
class GetSignup extends StatelessWidget {
GetTextField getTextField = GetTextField();
@override
Widget build(BuildContext context) {
return Expanded(
flex: 1,
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
GestureDetector(
onTap: () {
print('user name: ${getTextField.username}');
print('user email: {getTextField.email}');
print('user password: ${getTextField.password}');
},
child: CircleAvatar(
backgroundColor: Colors.grey.shade800,
radius: 40,
child: Icon(
Icons.arrow_back,
color: Colors.white,
),
),
),
Text(
"انشئ حسابك",
style: TextStyle(
fontSize: 25,
fontWeight: FontWeight.bold,
),
),
],
),
);
}
}
方法2：
class SignupScreen extends StatefulWidget {
static const id = "signup_screen";
@override
_SignupScreenState createState() => _SignupScreenState();
}
class _SignupScreenState extends State<SignupScreen> {
GetTextField getTextField = GetTextField();
@override
Widget build(BuildContext context) {
return Scaffold(
body: CustomPaint(
painter: BackgroundSignup(),
child: Stack(
children: <Widget>[
Padding(
padding: EdgeInsets.symmetric(
horizontal: 35,
),
child: Column(
children: <Widget>[
GetHeader(),
GetTextField(),
GetSignup(
username: getTextField.username,
email: getTextField.email,
password: getTextField.password,
),
GetButtonRow(),
],
),
),
GetBackButton(),
],
),
),
);
}
}
class GetTextField extends StatelessWidget {
String email;
String password;
String username;
@override
Widget build(BuildContext context) {
return Expanded(
flex: 4,
child: Column(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
SizedBox(
height: 15,
),
Directionality(
textDirection: TextDirection.rtl,
child: TextField(
onChanged: (value) {
username = value;
},
textAlign: TextAlign.start,
decoration: InputDecoration(
labelText: "الاسم كاملا",
labelStyle:
TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.white),
),
),
),
),
SizedBox(
height: 15,
),
Directionality(
textDirection: TextDirection.rtl,
child: TextField(
onChanged: (value) {
email = value;
},
textAlign: TextAlign.start,
decoration: InputDecoration(
labelText: "الإيميل",
labelStyle:
TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.white),
),
),
),
),
SizedBox(
height: 15,
),
Directionality(
textDirection: TextDirection.rtl,
child: TextField(
onChanged: (value) {
password = value;
},
obscureText: true,
textAlign: TextAlign.start,
decoration: InputDecoration(
labelText: "كلمة السر",
labelStyle:
TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.white),
),
),
),
),
SizedBox(
height: 25,
),
],
),
);
}
}
class GetSignup extends StatelessWidget {
final username;
final email;
final password;
GetSignup({this.username, this.email, this.password});
@override
Widget build(BuildContext context) {
return Expanded(
flex: 1,
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
GestureDetector(
onTap: () {
print('user name: $username');
print('user email: $email');
print('user password: $password');
},
child: CircleAvatar(
backgroundColor: Colors.grey.shade800,
radius: 40,
child: Icon(
Icons.arrow_back,
color: Colors.white,
),
),
),
Text(
"انشئ حسابك",
style: TextStyle(
fontSize: 25,
fontWeight: FontWeight.bold,
),
),
],
),
);
}
}
答案 0 :(得分：1)
像这样更新您的GetTextField类：
class GetTextField extends StatelessWidget {
Function(String) onEmail;
Function(String) onPassword;
Function(String) onUsername;
GetTextField({Key key, this.onEmail,this.onPassword,this.onUsername}) : super(key: key);
@override
Widget build(BuildContext context) {
return Expanded(
flex: 4,
child: Column(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
SizedBox(
height: 15,
),
Directionality(
textDirection: TextDirection.rtl,
child: TextField(
onChanged: onUsername,
textAlign: TextAlign.start,
decoration: InputDecoration(
labelText: "الاسم كاملا",
labelStyle:
TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.white),
),
),
),
),
SizedBox(
height: 15,
),
Directionality(
textDirection: TextDirection.rtl,
child: TextField(
onChanged: onEmail
textAlign: TextAlign.start,
decoration: InputDecoration(
labelText: "الإيميل",
labelStyle:
TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.white),
),
),
),
),
SizedBox(
height: 15,
),
Directionality(
textDirection: TextDirection.rtl,
child: TextField(
onChanged: onPassword
obscureText: true,
textAlign: TextAlign.start,
decoration: InputDecoration(
labelText: "كلمة السر",
labelStyle:
TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.white),
),
),
),
),
SizedBox(
height: 25,
),
],
),
);
}
像这样在SignupScreen中使用它：->
class SignupScreen extends StatefulWidget {
static const id = "signup_screen";
@override
_SignupScreenState createState() => _SignupScreenState();
}
class _SignupScreenState extends State<SignupScreen> {
String email="",username="",password="";
@override
Widget build(BuildContext context) {
return Scaffold(
body: CustomPaint(
painter: BackgroundSignup(),
child: Stack(
children: <Widget>[
Padding(
padding: EdgeInsets.symmetric(
horizontal: 35,
),
child: Column(
children: <Widget>[
GetHeader(),
GetTextField(
onEmail(email){
setState(() {
email = email;
});
},
onUsername(username){
setState(() {
username = username;
});
}
onPassword(pass){
setState(() {
password = pass;
});
}
),
GetSignup(
username: username,
email: email,
password: password,
),
GetButtonRow(),
],
),
),
GetBackButton(),
],
),
),
);
}
}
答案 1 :(得分：0)
首先：我尝试实现Shikhar Singh指令，但得到的输出相同：“用户名=空，电子邮件=空，密码=空”，这是修改后的代码”
class SignupScreen extends StatefulWidget {
static const id = "signup_screen";
@override
_SignupScreenState createState() => _SignupScreenState();
}
class _SignupScreenState extends State<SignupScreen> {
String email;
String username;
String password;
@override
Widget build(BuildContext context) {
return Scaffold(
body: CustomPaint(
painter: BackgroundSignup(),
child: Stack(
children: <Widget>[
Padding(
padding: EdgeInsets.symmetric(
horizontal: 35,
),
child: Column(
children: <Widget>[
GetHeader(),
GetTextField(
onEmail: (value) {
setState(() {
value = email;
});
},
onUsername: (value) {
setState(() {
value = username;
});
},
onPassword: (value) {
setState(() {
value = password;
});
},
),
GetSignup(
username: username,
email: email,
password: password,
),
GetButtonRow(),
],
),
),
GetBackButton(),
],
),
),
);
}
}
class GetTextField extends StatelessWidget {
Function(String) onEmail;
Function(String) onPassword;
Function(String) onUsername;
GetTextField({Key key, this.onEmail, this.onPassword, this.onUsername})
: super(key: key);
@override
Widget build(BuildContext context) {
return Expanded(
flex: 4,
child: Column(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
SizedBox(
height: 15,
),
Directionality(
textDirection: TextDirection.rtl,
child: TextField(
onChanged: onUsername,
textAlign: TextAlign.start,
decoration: InputDecoration(
labelText: "الاسم كاملا",
labelStyle:
TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.white),
),
),
),
),
SizedBox(
height: 15,
),
Directionality(
textDirection: TextDirection.rtl,
child: TextField(
onChanged: onEmail,
textAlign: TextAlign.start,
decoration: InputDecoration(
labelText: "الإيميل",
labelStyle:
TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.white),
),
),
),
),
SizedBox(
height: 15,
),
Directionality(
textDirection: TextDirection.rtl,
child: TextField(
onChanged: onPassword,
obscureText: true,
textAlign: TextAlign.start,
decoration: InputDecoration(
labelText: "كلمة السر",
labelStyle:
TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.white),
),
),
),
),
SizedBox(
height: 25,
),
],
),
);
}
}
class GetSignup extends StatelessWidget {
final username;
final email;
final password;
GetSignup({Key key, this.username, this.email, this.password})
: super(key: key);
@override
Widget build(BuildContext context) {
return Expanded(
flex: 1,
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
GestureDetector(
onTap: () {
//TODO: fill circle avatar
print('user name: $username');
print('user email: $email');
print('user password: $password');
},
child: CircleAvatar(
backgroundColor: Colors.grey.shade800,
radius: 40,
child: Icon(
Icons.arrow_back,
color: Colors.white,
),
),
),
Text(
"انشئ حسابك",
style: TextStyle(
fontSize: 25,
fontWeight: FontWeight.bold,
),
),
],
),
);
}
}