您好，我一直在尝试在Flutter中实现Willpopscope，但此回调功能仍然无法正常工作，它仍然关闭或返回上一屏幕，并且我希望在用户按下后退时显示警报对话框按钮，而不是显示对话框，而是返回上一个屏幕。请帮我哪里做错了。
编辑代码
import 'package:deep6/audio_player/click_player.dart';
import 'package:deep6/main_menu.dart';
import 'package:deep6/utility/countDown.dart';
import 'package:deep6/utility/preference.dart';
import 'package:flutter/material.dart';
import
'package:flutter_local_notifications/flutter_local_notifications.dart';
import 'package:shared_preferences/shared_preferences.dart';
class SceneStory extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
debugShowCheckedModeBanner: false,
home: Scene(
character: null,
text: null,
mainTextColor: null,
avatar: null,
lbText: null,
lbTextTarget: null,
lbTextColor: null,
rbText: null,
rbTextTarget: null,
rbTextColor: null,
),
);
}
}
class Scene extends StatefulWidget {
List<String> character = new List<String>();
List<String> text = new List<String>();
List<List<int>> mainTextColor = new List<List<int>>();
List<String> avatar = new List<String>();
List<String> lbText = new List<String>();
List<int> lbTextTarget = new List<int>();
List<List<int>> lbTextColor = new List<List<int>>();
List<String> rbText = new List<String>();
List<int> rbTextTarget = new List<int>();
List<List<int>> rbTextColor = new List<List<int>>();
Scene(
{Key key,
this.character,
this.text,
this.mainTextColor,
this.avatar,
this.lbText,
this.lbTextTarget,
this.lbTextColor,
this.rbText,
this.rbTextTarget,
this.rbTextColor})
: super(key: key);
@override
SceneState createState() => new SceneState();
}
String name, text, buttonLeftText, buttonRightText;
String avatar = 'assets/images/profile_cure.png';
int sceneId, leftTarget, rightTarget;
class SceneState extends State<Scene> with TickerProviderStateMixin {
double width, height;
List<String> content = new List<String>();
CountDown customTimer;
PrefsKeys prefs;
int mainIndex = 0;
bool isEnabled = false;
List<String> character = new List<String>();
List<String> text = new List<String>();
List<List<int>> mainTextColor = new List<List<int>>();
List<String> avatar = new List<String>();
List<String> lbText = new List<String>();
List<int> lbTextTarget = new List<int>();
List<List<int>> lbTextColor = new List<List<int>>();
List<String> rbText = new List<String>();
List<int> rbTextTarget = new List<int>();
List<List<int>> rbTextColor = new List<List<int>>();
Image charImage;
Text charName, mainText, leftText, rightText;
MaterialButton leftButton, rightButton;
ClickPlayer cPlay;
AnimationController controller;
@override
void initState() {
super.initState();
character = widget.character;
text = widget.text;
mainTextColor = widget.mainTextColor;
avatar = widget.avatar;
lbText = widget.lbText;
lbTextTarget = widget.lbTextTarget;
lbTextColor = widget.lbTextColor;
rbText = widget.rbText;
rbTextTarget = widget.rbTextTarget;
rbTextColor = widget.rbTextColor;
animation();
cPlay = new ClickPlayer();
preference();
}
void preference() async {
SharedPreferences pref = await SharedPreferences.getInstance().then((pref)
{
pref.setBool(PrefsKeys.bool_continuation, true);
});
}
void animation() async {
controller = new AnimationController(
duration: const Duration(milliseconds: 4000), vsync: this);
await controller.forward();
controller.dispose();
}
Future onSelectNotification(String payload) async {
if (payload != null) {
debugPrint('notification payload: ' + payload);
}
Navigator.pushReplacement(
context,
MaterialPageRoute(
builder: (context) => MenuScreen(),
),
);
print("Notifications is Clicked $payload");
}
void showNotification() async {
FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin;
var initializationSettingsAndroid;
var initializationSettingsIOS;
var initializationSettings;
flutterLocalNotificationsPlugin = new FlutterLocalNotificationsPlugin();
initializationSettingsAndroid =
new AndroidInitializationSettings('ic_launcher');
initializationSettingsIOS = new IOSInitializationSettings();
initializationSettings = new InitializationSettings(
initializationSettingsAndroid, initializationSettingsIOS);
flutterLocalNotificationsPlugin.initialize(initializationSettings,
selectNotification: onSelectNotification);
var scheduledNotificationDateTime =
new DateTime.now().add(new Duration(minutes: 2));
var androidPlatformChannelSpecifics = new AndroidNotificationDetails(
'0', 'Anas', 'Notification',
importance: Importance.Max, priority: Priority.High);
var iOSPlatformChannelSpecifics = new IOSNotificationDetails();
var platformChannelSpecifics = new NotificationDetails(
androidPlatformChannelSpecifics, iOSPlatformChannelSpecifics);
await flutterLocalNotificationsPlugin.schedule(
0,
'DEEP 6',
'NOW YOU CAN CONTINUE.',
scheduledNotificationDateTime,
platformChannelSpecifics);
print("Inside Notifications class");
}
void leftButtonClick() async {
cPlay.playClick();
mainIndex = lbTextTarget[mainIndex];
print("$mainIndex mainindex");
if (mainIndex == 18) {
showNotification();
SharedPreferences pref =
await SharedPreferences.getInstance().then((pref) {
pref.setInt(
PrefsKeys.str_timestamp, new
DateTime.now().millisecondsSinceEpoch);
pref.setString(PrefsKeys.str_character, character[mainIndex]);
pref.setString(PrefsKeys.str_mainText, text[mainIndex]);
pref.setString(PrefsKeys.str_avatar, avatar[mainIndex]);
pref.setString(PrefsKeys.str_lbText, lbText[mainIndex]);
List<String> color = new List<String>();
color.add(mainTextColor[mainIndex][0].toString());
color.add(mainTextColor[mainIndex][1].toString());
color.add(mainTextColor[mainIndex][2].toString());
pref.setStringList(PrefsKeys.list_color, color);
Navigator.pushReplacement(
context,
MaterialPageRoute(
builder: (context) => MainMenu(),
),
);
});
} else {
isEnabled = false;
setState(() {
charImage = null;
charName = null;
mainText = null;
leftText = null;
rightText = null;
charImage = new Image.asset(
avatar[mainIndex],
fit: BoxFit.contain,
height: height * 0.2,
);
charName = new Text(
character[mainIndex],
style: new TextStyle(
color: Color.fromRGBO(mainTextColor[mainIndex][0],
mainTextColor[mainIndex][1], mainTextColor[mainIndex][2],
1.0),
fontSize: 20.0,
),
);
mainText = new Text(
text[mainIndex],
style: new TextStyle(
color: Color.fromRGBO(mainTextColor[mainIndex][0],
mainTextColor[mainIndex][1], mainTextColor[mainIndex][2],
1.0),
fontSize: 22.0,
),
textAlign: TextAlign.start,
);
animation();
leftText = new Text(
lbText[mainIndex],
style: new TextStyle(
color: Color.fromRGBO(lbTextColor[mainIndex][0],
lbTextColor[mainIndex][1], lbTextColor[mainIndex][2], 1.0)),
textAlign: TextAlign.center,
softWrap: true,
maxLines: 10,
);
if (rbText[mainIndex] == "") {
rightText = null;
rightButton = new MaterialButton(
key: null,
onPressed: () {},
color: Color.fromRGBO(0, 0, 0, 0.8),
height: 0.0,
minWidth: 0.0,
child: null,
);
} else {
rightText = new Text(
rbText[mainIndex],
style: new TextStyle(
color: Color.fromRGBO(rbTextColor[mainIndex][0],
rbTextColor[mainIndex][1], rbTextColor[mainIndex][2], 1.0),
),
textAlign: TextAlign.center,
);
}
});
}
}
void rightButtonClick() async {
cPlay.playClick();
mainIndex = rbTextTarget[mainIndex];
print("$mainIndex mainindex");
if (mainIndex == 18) {
showNotification();
SharedPreferences pref =
await SharedPreferences.getInstance().then((pref) {
pref.setInt(
PrefsKeys.str_timestamp, new DateTime.now().millisecondsSinceEpoch);
Navigator.pushReplacement(
context,
MaterialPageRoute(
builder: (context) => MainMenu(),
),
);
});
} else {
isEnabled = false;
setState(() {
charImage = null;
charName = null;
mainText = null;
leftText = null;
rightText = null;
charImage = new Image.asset(
avatar[mainIndex],
fit: BoxFit.contain,
height: height * 0.2,
);
charName = new Text(
character[mainIndex],
style: new TextStyle(
color: Color.fromRGBO(mainTextColor[mainIndex][0],
mainTextColor[mainIndex][1], mainTextColor[mainIndex][2], 1.0),
fontSize: 22.0,
),
);
mainText = new Text(
text[mainIndex],
style: new TextStyle(
color: Color.fromRGBO(mainTextColor[mainIndex][0],
mainTextColor[mainIndex][1], mainTextColor[mainIndex][2], 1.0),
fontSize: 20.0,
),
textAlign: TextAlign.start,
);
animation();
leftText = new Text(
lbText[mainIndex],
style: new TextStyle(
color: Color.fromRGBO(lbTextColor[mainIndex][0],
lbTextColor[mainIndex][1], lbTextColor[mainIndex][2], 1.0)),
textAlign: TextAlign.center,
softWrap: true,
maxLines: 10,
);
if (rbText[mainIndex] == "") {
rightText = null;
rightButton = new MaterialButton(
key: null,
onPressed: () {},
color: Color.fromRGBO(0, 0, 0, 0.8),
height: 0.0,
minWidth: 0.0,
child: null,
);
} else {
rightText = new Text(
rbText[mainIndex],
style: new TextStyle(
color: Color.fromRGBO(rbTextColor[mainIndex][0],
rbTextColor[mainIndex][1], rbTextColor[mainIndex][2], 1.0),
),
textAlign: TextAlign.center,
);
}
});
}
}
Future<bool> _showDialog() {
print("Show dialog");
return showDialog(
context: context,
builder: (BuildContext contxt) {
return AlertDialog(
title: new Text(
"Exit!!!",
style: TextStyle(color: Colors.black),
),
content: new Text(
"Are You sure you want to exit?",
style: TextStyle(color: Colors.black),
),
actions: <Widget>[
new FlatButton(
child: new Text(
"Yes",
style: TextStyle(color: Colors.blue),
),
onPressed: null,
)
],
);
});
}
@override
Widget build(BuildContext context) {
final mediaQueryData = MediaQuery.of(context);
width = mediaQueryData.size.width;
height = mediaQueryData.size.height;
Animation<int> _characterCount = new StepTween(
begin: 0, end: text[mainIndex].length)
.animate(new CurvedAnimation(parent: controller, curve: Curves.easeIn));
controller.addStatusListener((status) {
if (status == AnimationStatus.completed) {
isEnabled = true;
}
});
charImage = new Image.asset(
avatar[mainIndex],
fit: BoxFit.contain,
height: height * 0.2,
);
charName = new Text(
character[mainIndex],
style: new TextStyle(
color: Color.fromRGBO(mainTextColor[mainIndex][0],
mainTextColor[mainIndex][1], mainTextColor[mainIndex][2], 1.0),
fontSize: 22.0,
),
);
mainText = new Text(
text[mainIndex],
style: new TextStyle(
color: Color.fromRGBO(mainTextColor[mainIndex][0],
mainTextColor[mainIndex][1], mainTextColor[mainIndex][2], 1.0),
fontSize: 20.0,
),
textAlign: TextAlign.start,
);
leftText = new Text(
lbText[mainIndex],
style: new TextStyle(
color: Color.fromRGBO(lbTextColor[mainIndex][0],
lbTextColor[mainIndex][1], lbTextColor[mainIndex][2], 1.0)),
textAlign: TextAlign.center,
softWrap: true,
maxLines: 10,
);
rightText = new Text(
rbText[mainIndex],
style: new TextStyle(
color: Color.fromRGBO(rbTextColor[mainIndex][0],
rbTextColor[mainIndex][1], rbTextColor[mainIndex][2], 1.0),
),
textAlign: TextAlign.center,
);
leftButton = new MaterialButton(
key: null,
onPressed: () {
if (isEnabled) {
leftButtonClick();
}
},
color: Color.fromRGBO(0, 0, 0, 0.8),
height: height * 0.2,
minWidth: width * 0.49,
child: new Container(
child: leftText,
),
);
rightButton = new MaterialButton(
key: null,
onPressed: () {
if (isEnabled) {
rightButtonClick();
}
},
color: Color.fromRGBO(0, 0, 0, 0.8),
height: height * 0.2,
minWidth: width * 0.49,
child: rightText,
);
return new WillPopScope(
child: new Scaffold(
backgroundColor: new Color(0xFF000000),
body: new Container(
height: double.infinity,
width: double.infinity,
decoration: new BoxDecoration(
image: DecorationImage(
image: new AssetImage('assets/images/blury_background.png'),
fit: BoxFit.fill)),
child: new Column(
mainAxisAlignment: MainAxisAlignment.spaceAround,
mainAxisSize: MainAxisSize.max,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
charImage,
new Container(
padding: const EdgeInsets.fromLTRB(0.0, 5.0, 0.0, 5.0),
child: new Center(
child: charName,
),
color: Color.fromRGBO(0, 0, 0, 0.8),
),
new AnimatedBuilder(
animation: _characterCount,
builder: (BuildContext context, Widget child) {
String txt =
text[mainIndex].substring(0, _characterCount.value);
return new Container(
color: Color.fromRGBO(0, 0, 0, 0.8),
child: new Text(
txt,
style: new TextStyle(
color: Color.fromRGBO(
mainTextColor[mainIndex][0],
mainTextColor[mainIndex][1],
mainTextColor[mainIndex][2],
1.0),
fontSize: 20.0,
),
textAlign: TextAlign.start,
),
padding: const EdgeInsets.all(20.0),
//fromLTRB(12.0, 0.0, 5.0, 0.0),
height: height * 0.5,
);
}),
new Row(
mainAxisAlignment: MainAxisAlignment.spaceAround,
mainAxisSize: MainAxisSize.max,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
new Container(
child: leftButton,
),
new Container(
child: rightButton,
),
],
),
]),
),
),
onWillPop: () {
print("on back is pressed");
},
);
}
}
这是我全班的代码。现在，如果我做错了，请帮助我。
答案 0 :(得分：0)
尝试仅将body包装在WillPopScope中，而不是整个Scaffold
UPD
如果我理解正确-您可以通过以下方式调用此屏幕：
Navigator.of(context).push(MaterialPageRoute(builder: (context) => SceneStory()));
那样做
Navigator.of(context).push(MaterialPageRoute(builder: (context) => Scene()));