问题：
颤振：在屏幕开始处实现权限处理程序
上官波鸿
Permission\u处理程序。飞奔
import 'package:flutter/material.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:status_saver/utils/splash_screen.dart';
class PermissionHandler extends StatefulWidget {
const PermissionHandler({ Key? key }) : super(key: key);
@override
_PermissionHandlerState createState() => _PermissionHandlerState();
}
class _PermissionHandlerState extends State<PermissionHandler> {
Future<Widget> permissionCheck() async {
var permissionStatus = await Permission.storage.status;
if (!permissionStatus.isGranted){
await Permission.storage.request();
}
permissionStatus = await Permission.storage.status;
if(permissionStatus.isGranted) return SplashScreen();
else {
return AlertDialog(
title: Text('Permission Required'), // To display the title it is optional
content: Text('Cannot proceed without permission'), // Message which will be pop up on the screen
// Action widget which will provide the user to acknowledge the choice
actions: [
TextButton( // FlatButton widget is used to make a text to work like a button
child: Text('Open App Settings'),
onPressed: () => openAppSettings(),
// function used to perform after pressing the button
),
],
);
}
}
@override
Widget build(BuildContext context) {
return FutureBuilder(
builder: (ctx, snapshot) {
// Checking if future is resolved or not
if (snapshot.connectionState == ConnectionState.done) {
// If we got an error
if (snapshot.hasError) {
return Center(
child: Text(
'${snapshot.error} occured',
style: TextStyle(fontSize: 18),
),
);
// if we got our data
} else {
return snapshot.data as Widget;
}
}
// Displaying LoadingSpinner to indicate waiting state
return Center(
child: CircularProgressIndicator(),
);
},
// Future that needs to be resolved
// inorder to display something on the Canvas
future: permissionCheck(),
);
}
}
主要的飞奔
import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:status_saver/services/permission_handler.dart';
import 'package:status_saver/utils/router.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return GetMaterialApp(
title: 'Hello World',
debugShowCheckedModeBanner: false,
onGenerateRoute: AppRouter.generateRoute,
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: PermissionHandler(),
);
}
}
>
在应用程序开始时，我想请求存储权限我做了什么-创建类PermissionHandler并将其分配给属性
PermissionHandler（）-有状态小部件，应在完成其业务逻辑后触发splashscreen
- 请求用户权限，直到用户授予它
- 在应用程序启动时一次性请求权限，如果接受，则加载启动屏幕，否则会弹出一个新对话框，将用户带到应用程序设置
return Center(
child: CircularProgressIndicator(),
);
[ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: PlatformException(PermissionHandler.PermissionManager, A request for permissions is
already running, please wait for it to finish before doing another request (note that you can request multiple permissions at the same time)., null, null)
[ ] E/flutter ( 787): #0 StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:607:7)
[ ] E/flutter ( 787): #1 MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:156:18)
[ ] E/flutter ( 787): <asynchronous suspension>
[ ] E/flutter ( 787): #2 MethodChannelPermissionHandler.requestPermissions
(package:permission_handler_platform_interface/src/method_channel/method_channel_permission_handler.dart:71:9)
[ ] E/flutter ( 787): <asynchronous suspension>
[ ] E/flutter ( 787): #3 _PermissionHandlerScreenState.permissionServices (package:status_saver/services/permission_handler.dart:38:50)
[ ] E/flutter ( 787): <asynchronous suspension>
[ ] E/flutter ( 787): #4 _PermissionHandlerScreenState.permissionServiceCall (package:status_saver/services/permission_handler.dart:19:5)
[ ] E/flutter ( 787): <asynchronous suspension>
[ ] E/flutter ( 787):
按下拒绝按钮时引发错误
从应用程序设置授予权限后，抛出错误：清单中没有为以下内容定义权限：[]
清单文件定义了存储权限，（我删除了相机和麦克风的代码以便于测试，因此它们不是问题）
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
共有1个答案
孙修德
请参考以下示例代码
解决方案1：限制用户导航到任何其他路线/屏幕，而不允许所述的所有权限
class MyApp extends StatelessWidget {
MyApp({Key key}) : super(key: key);
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primaryColor: Color(0xfff00B074),
textTheme: const TextTheme(
bodyText1: TextStyle(
fontSize: 18.0,
fontFamily: 'Barlow-Medium',
color: Color(0xff464255)),
),
),
home: PermissionHandlerScreen(),
);
}
}
class PermissionHandlerScreen extends StatefulWidget {
@override
_PermissionHandlerScreenState createState() =>
_PermissionHandlerScreenState();
}
class _PermissionHandlerScreenState extends State<PermissionHandlerScreen> {
@override
void initState() {
super.initState();
permissionServiceCall();
}
permissionServiceCall() async {
await permissionServices().then(
(value) {
if (value != null) {
if (value[Permission.storage].isGranted &&
value[Permission.camera].isGranted &&
value[Permission.microphone].isGranted) {
/* ========= New Screen Added ============= */
Navigator.pushReplacement(
context,
MaterialPageRoute(builder: (context) => SplashScreen()),
);
}
}
},
);
}
/*Permission services*/
Future<Map<Permission, PermissionStatus>> permissionServices() async {
// You can request multiple permissions at once.
Map<Permission, PermissionStatus> statuses = await [
Permission.storage,
Permission.camera,
Permission.microphone,
//add more permission to request here.
].request();
if (statuses[Permission.storage].isPermanentlyDenied) {
await openAppSettings().then(
(value) async {
if (value) {
if (await Permission.storage.status.isPermanentlyDenied == true &&
await Permission.storage.status.isGranted == false) {
openAppSettings();
// permissionServiceCall(); /* opens app settings until permission is granted */
}
}
},
);
} else {
if (statuses[Permission.storage].isDenied) {
permissionServiceCall();
}
}
if (statuses[Permission.microphone].isPermanentlyDenied) {
await openAppSettings().then(
(value) async {
if (value) {
if (await Permission.microphone.status.isPermanentlyDenied == true &&
await Permission.microphone.status.isGranted == false) {
openAppSettings();
// permissionServiceCall(); /* opens app settings until permission is granted */
}
}
},
);
} else {
if (statuses[Permission.microphone].isDenied) {
permissionServiceCall();
}
}
if (statuses[Permission.camera].isPermanentlyDenied) {
await openAppSettings().then(
(value) async {
if (value) {
if (await Permission.camera.status.isPermanentlyDenied == true &&
await Permission.camera.status.isGranted == false) {
openAppSettings();
// permissionServiceCall(); /* opens app settings until permission is granted */
}
}
},
);
//openAppSettings();
//setState(() {});
} else {
if (statuses[Permission.camera].isDenied) {
permissionServiceCall();
}
}
/*{Permission.camera: PermissionStatus.granted, Permission.storage: PermissionStatus.granted}*/
return statuses;
}
@override
Widget build(BuildContext context) {
permissionServiceCall();
return WillPopScope(
onWillPop: () {
SystemNavigator.pop();
},
child: Scaffold(
body: Container(
child: Center(
child: InkWell(
onTap: () {
permissionServiceCall();
},
child: Text("Click here to enable Enable Permission Screen")),
),
),
),
);
}
}
class SplashScreen extends StatelessWidget {
const SplashScreen({Key key}) : super(key: key);
@override
Widget build(BuildContext context) {
return WillPopScope(
onWillPop: () {
SystemNavigator.pop();
},
child: Scaffold(
body: Center(
child: Text(
"Splash Screen",
),
),
),
);
}
}
解决方案2：
class MyApp extends StatelessWidget {
MyApp({Key key}) : super(key: key);
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primaryColor: Color(0xfff00B074),
textTheme: const TextTheme(
bodyText1: TextStyle(
fontSize: 18.0,
fontFamily: 'Barlow-Medium',
color: Color(0xff464255)),
),
),
home: PermissionHandlerScreen(),
);
}
}
class PermissionHandlerScreen extends StatefulWidget {
@override
_PermissionHandlerScreenState createState() =>
_PermissionHandlerScreenState();
}
class _PermissionHandlerScreenState extends State<PermissionHandlerScreen> {
@override
void initState() {
super.initState();
permissionServiceCall();
}
permissionServiceCall() async {
await permissionServices().then(
(value) {
if (value != null) {
if (value[Permission.storage].isGranted &&
value[Permission.camera].isGranted &&
value[Permission.microphone].isGranted) {
/* ========= New Screen Added ============= */
Navigator.pushReplacement(
context,
MaterialPageRoute(builder: (context) => SplashScreen()),
);
}
}
},
);
}
/*Permission services*/
Future<Map<Permission, PermissionStatus>> permissionServices() async {
// You can request multiple permissions at once.
Map<Permission, PermissionStatus> statuses = await [
Permission.storage,
Permission.camera,
Permission.microphone,
//add more permission to request here.
].request();
if (statuses[Permission.storage].isPermanentlyDenied) {
openAppSettings();
//setState(() {});
} else {
if (statuses[Permission.storage].isDenied) {
permissionServiceCall();
}
}
if (statuses[Permission.microphone].isPermanentlyDenied) {
openAppSettings();
// setState(() {});
} else {
if (statuses[Permission.microphone].isDenied) {
permissionServiceCall();
}
}
if (statuses[Permission.camera].isPermanentlyDenied) {
openAppSettings();
// setState(() {});
} else {
if (statuses[Permission.camera].isDenied) {
permissionServiceCall();
}
}
/*{Permission.camera: PermissionStatus.granted, Permission.storage: PermissionStatus.granted}*/
return statuses;
}
@override
Widget build(BuildContext context) {
return WillPopScope(
onWillPop: () {
SystemNavigator.pop();
},
child: Scaffold(
body: Container(
child: Center(
child: InkWell(
onTap: () {
permissionServiceCall();
},
child: Text("Click here to enable Enable Permissions")),
),
),
),
);
}
}
class SplashScreen extends StatelessWidget {
const SplashScreen({Key key}) : super(key: key);
@override
Widget build(BuildContext context) {
return WillPopScope(
onWillPop: () {
SystemNavigator.pop();
},
child: Scaffold(
body: Center(
child: Text(
"Splash Screen",
),
),
),
);
}
}
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