位置包示例对我不起作用 Flutter

Question

我是新来的，并试图从我的移动应用程序中获取当前位置的纬度和经度，为此我使用的是位置 1.4.1，并且还找到了我在下面的链接中提到的这个示例，我完全按照他们提到的步骤进行了操作一步一步的过程，但仍然是它的抛出错误。

请通过示例

Exception has occurred.
PlatformException(PERMISSION_DENIED, The user explicitly denied the use of location services for this app or location services are currently disabled in Settings., null)

这是我运行代码时遇到的异常，但在该示例中有一个针对 PlatformException 的 try catch。我卡在这里，请帮帮我，谢谢。

我的 AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.latlong">

    <!-- The INTERNET permission is required for development. Specifically,
         flutter needs it to communicate with the running application
         to allow setting breakpoints, to provide hot reload, etc.
    -->
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

    <!-- io.flutter.app.FlutterApplication is an android.app.Application that
         calls FlutterMain.startInitialization(this); in its onCreate method.
         In most cases you can leave this as-is, but you if you want to provide
         additional functionality it is fine to subclass or reimplement
         FlutterApplication and put your custom class here. -->
    <application
        android:name="io.flutter.app.FlutterApplication"
        android:label="lat_long"
        android:icon="@mipmap/ic_launcher">
        <activity
            android:name=".MainActivity"
            android:launchMode="singleTop"
            android:theme="@style/LaunchTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density"
            android:hardwareAccelerated="true"
            android:windowSoftInputMode="adjustResize">
            <!-- This keeps the window background of the activity showing
                 until Flutter renders its first frame. It can be removed if
                 there is no splash screen (such as the default splash screen
                 defined in @style/LaunchTheme). -->
            <meta-data
                android:name="io.flutter.app.android.SplashScreenUntilFirstFrame"
                android:value="true" />
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
    </application>
</manifest>

主要.dart：

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:location/location.dart';

void main() {
  runApp(new MyApp());
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => new _MyAppState();
}

class _MyAppState extends State<MyApp> {
  Map<String, double> _startLocation;
  Map<String, double> _currentLocation;

  StreamSubscription<Map<String, double>> _locationSubscription;

  Location _location = new Location();
  bool _permission = false;
  String error;

  bool currentWidget = true;

  Image image1;

  @override
  void initState() {
    super.initState();

    initPlatformState();

    _locationSubscription =
        _location.onLocationChanged().listen((Map<String,double> result) {
          setState(() {
            _currentLocation = result;
          });
        });
  }

  // Platform messages are asynchronous, so we initialize in an async method.
  initPlatformState() async {
    Map<String, double> location;
    // Platform messages may fail, so we use a try/catch PlatformException.

    try {
      _permission = await _location.hasPermission();
      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;
    }

    // If the widget was removed from the tree while the asynchronous platform
    // message was in flight, we want to discard the reply rather than calling
    // setState to update our non-existent appearance.
    //if (!mounted) return;

    setState(() {
        _startLocation = location;
    });

  }

  @override
  Widget build(BuildContext context) {
    List<Widget> widgets;


    if (_currentLocation == null) {
      widgets = new List();
    } else {
      widgets = [
        new Image.network(
            "https://maps.googleapis.com/maps/api/staticmap?"+
            "center=${_currentLocation["latitude"]},${_currentLocation["longitude"]}"+
            "&zoom=18&size=640x400&key=xxxxxxxxxxx")
      ];
    }

    widgets.add(new Center(
        child: new Text(_startLocation != null
            ? 'Start location: $_startLocation\n'
            : 'Error: $error\n')));

    widgets.add(new Center(
        child: new Text(_currentLocation != null
            ? 'Continuous location: $_currentLocation\n'
            : 'Error: $error\n')));

    widgets.add(new Center(
      child: new Text(_permission 
            ? 'Has permission : Yes' 
            : "Has permission : No")));

    return new MaterialApp(
        home: new Scaffold(
            appBar: new AppBar(
              title: new Text('Location plugin example app'),
            ),
            body: new Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              mainAxisSize: MainAxisSize.min,
              children: widgets,
            )));
  }
}

和我的 pubspec.yaml ：

name: lat_long
description: A new Flutter project.

dependencies:
  flutter:
    sdk: flutter

  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^0.1.2
  location: ^1.4.1

dev_dependencies:
  flutter_test:
    sdk: flutter


# For information on the generic Dart part of this file, see the
# following page: https://www.dartlang.org/tools/pub/pubspec

# The following section is specific to Flutter.
flutter:

  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
  uses-material-design: true

  # To add assets to your application, add an assets section, like this:
  # assets:
  #  - images/a_dot_burr.jpeg
  #  - images/a_dot_ham.jpeg

  # An image asset can refer to one or more resolution-specific "variants", see
  # https://flutter.io/assets-and-images/#resolution-aware.

  # For details regarding adding assets from package dependencies, see
  # https://flutter.io/assets-and-images/#from-packages

  # To add custom fonts to your application, add a fonts section here,
  # in this "flutter" section. Each entry in this list should have a
  # "family" key with the font family name, and a "fonts" key with a
  # list giving the asset and other descriptors for the font. For
  # example:
  # fonts:
  #   - family: Schyler
  #     fonts:
  #       - asset: fonts/Schyler-Regular.ttf
  #       - asset: fonts/Schyler-Italic.ttf
  #         style: italic
  #   - family: Trajan Pro
  #     fonts:
  #       - asset: fonts/TrajanPro.ttf
  #       - asset: fonts/TrajanPro_Bold.ttf
  #         weight: 700
  #
  # For details regarding fonts from package dependencies,
  # see https://flutter.io/custom-fonts/#from-packages

Answer 1

我在少数 android 设备上遇到了同样的问题。但我已经找到了解决办法——

您需要做的就是设置 Geolocator()..forceAndroidLocationManager = true 的值。

final Geolocator geolocator = Geolocator()..forceAndroidLocationManager = true;