下面的代码在 Android 上运行顺利,但在 iOS 上卡住了,当我单击地图图标时,系统应该更新我的位置:
import 'package:flutter/material.dart';
import 'package:location/location.dart';
import 'package:flutter/services.dart';
import 'package:simple_permissions/simple_permissions.dart';
class LocationState extends State {
String _loca_ext;
Location _location = new Location();
Map<String, double> _currentLocation;
String error;
@override
void initState() {
super.initState();
setState(() {
_loca_ext = 'Clik to update location';
});
}
// Platform messages are asynchronous, so we initialize in an async method.
_getLocation() async {
Map<String, double> location;
// Platform messages may fail, so we use a try/catch PlatformException.
try {
await SimplePermissions.requestPermission(Permission.AccessFineLocation);
location = await _location.getLocation();
error = null;
} on PlatformException catch (e) {
if (e.code == 'PERMISSION_DENIED') {
error = 'Permission denied';
} else if (e.code == 'PERMISSION_DENIED_NEVER_ASK') {
error =
'Permission denied - please ask the user to enable it from the app settings';
}
location = null;
}
print("error $error");
setState(() {
_currentLocation = location;
_loca_ext = ('${_currentLocation["latitude"]}, ${_currentLocation["longitude"]}' ?? 'Grant location Access');
print(_currentLocation);
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text('Baby Name Votes')),
body: _buildBody(context),
);
}
Widget _buildBody(BuildContext context) {
return Padding(
padding: const EdgeInsets.symmetric(horizontal: 16.0, vertical: 8.0),
child: Container(
decoration: BoxDecoration(
border: Border.all(color: Colors.grey),
borderRadius: BorderRadius.circular(5.0),
),
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
ButtonTheme.bar(
child: ButtonBar(
children: <Widget>[
Text.rich(
TextSpan(text: '$_loca_ext'),
),
FlatButton(
child: const Icon(Icons.map),
onPressed: () {
_getLocation();
var alt = _currentLocation["latitude"];
print("my $alt at location is: $_currentLocation");
},
)
])
)
]),
),
);
}
}
在 iOS 上,出现以下错误:
错误权限被拒绝
知道在
Info.plist
中,我添加了以下内容:
<key>NSLocationWhenInUseUsageDescription</key>
<string>This app needs access to location in the background.</string>
<key>NSLocationAlwaysUsageDescription</key>
<string>This app needs access to location when in the background.</string>
<key>NSLocationAlwaysAndWhenInUseUsageDescription</key>
<string>This app needs access to location when open and in the background.</string>
注意
如果我在
settings/privacy/location
中手动授予它,它就可以工作,但我需要以编程方式执行此操作,或者引导用户执行此操作。
您尝试过使用https://pub.dev/packages/permission吗?
示例方法:
import 'package:permission/permission.dart';
var permissions = await Permission.getPermissionsStatus([PermissionName.Calendar, PermissionName.Camera]);
var permissionNames = await Permission.requestPermissions([PermissionName.Calendar, PermissionName.Camera]);
Permission.openSettings;
但是就像评论说的,如果权限被拒绝,那么你必须手动进入设置来启用它。如需更多了解,请参阅medium/在 iOS 中请求位置权限(2018 年 3 月)
用户只有一次机会响应这些警报,因此您希望 在适当的时间提出请求并提供充分的理由。 如果用户不允许访问,他们需要转到设置 启用位置访问。
在我的例子中,我使用 FlutterMap 和 CurrentLocationLayer,它内部使用 Geolocator。因此,当我尝试询问当前位置并同时显示地图时,会抛出异常。
真正奇怪的是,这种情况只发生在 iOS 上,而不是 Android 上。无论如何,知道原因后,您可以通过仅在确定拥有许可时才显示此层来阻止它(或者即使您没有,至少在您已经请求时)。