为什么谷歌地图不会显示在flutter中？

Question

我已经从谷歌云生成了一个API密钥，并且还启用了适用于android和ios的Maps SDK。我还在 AndroidManifest.xml 中输入了 API 密钥。但地图不会显示，只是灰屏。就像下面这个一样。 那么这个问题的最终解决方案是什么呢？

AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.ambulance_tracker">
    <!-- 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="ambulance_tracker"
        android:icon="@mipmap/ic_launcher">
        <activity
            android:name=".MainActivity"
            android:launchMode="singleTop"
            android:theme="@style/LaunchTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
            android:hardwareAccelerated="true"
            android:windowSoftInputMode="adjustResize">
            <!-- Specifies an Android theme to apply to this Activity as soon as
                 the Android process has started. This theme is visible to the user
                 while the Flutter UI initializes. After that, this theme continues
                 to determine the Window background behind the Flutter UI. -->
            <meta-data
              android:name="io.flutter.embedding.android.NormalTheme"
              android:resource="@style/NormalTheme"
              />
            <!-- Displays an Android View that continues showing the launch screen
                 Drawable until Flutter paints its first frame, then this splash
                 screen fades out. A splash screen is useful to avoid any visual
                 gap between the end of Android's launch screen and the painting of
                 Flutter's first frame. -->
            <meta-data
              android:name="io.flutter.embedding.android.SplashScreenDrawable"
              android:resource="@drawable/launch_background"
              />
            
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
        <!-- Don't delete the meta-data below.
             This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
        <meta-data
            android:name="flutterEmbedding"
            android:value="2" />
            <meta-data android:name="com.google.android.geo.API_KEY"
              android:value="key=AIzaSyAvQUefjL5----------------"/>
    </application>
</manifest>

---

gmap.dart() 文件：

import 'dart:collection';

import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';

class GMap extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: Scaffold(
        appBar: AppBar(
          backgroundColor: Colors.deepPurple,
        ),
        body: SingleChildScrollView(
          child: Column(
            children: <Widget>[
              Padding(
                padding: const EdgeInsets.only(top: 8.0),
                child: Container(
                  height: MediaQuery.of(context).size.height / 2,
                  width: MediaQuery.of(context).size.width,
                  child: GoogleMap(
                    initialCameraPosition:
                        CameraPosition(target: LatLng(29.9792, 31.1342)),
                    zoomGesturesEnabled: true,
                  ),
                ),
              )
            ],
          ),
        ),
      ),
    );
  }
}

---

main.dart()

import 'package:ambulance_tracker/Screens/gmap.dart';
import 'package:flutter/material.dart';
import 'package:location/location.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'GMap Try',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.deepPurple,
      ),
      home: GMap(),
    );
  }
}

---

pubspec.yaml：

name: ambulance_tracker
description: A new Flutter project.

# The following line prevents the package from being accidentally published to
# pub.dev using `pub publish`. This is preferred for private packages.
publish_to: 'none' # Remove this line if you wish to publish to pub.dev

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# In Android, build-name is used as versionName while build-number used as versionCode.
# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
# Read more about iOS versioning at
# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
version: 1.0.0+1

environment:
  sdk: ">=2.7.0 <3.0.0"

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: ^0.1.3
  firebase_auth: ^0.18.0+1
  firebase_core: ^0.5.0
  flutter_svg: ^0.18.0
  google_maps_flutter: ^0.5.32
  location: ^2.5.0
  
dev_dependencies:
  flutter_test:
    sdk: flutter

# For information on the generic Dart part of this file, see the
# following page: https://dart.dev/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:
    - assets/images/
  #   - images/a_dot_ham.jpeg

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

  # For details regarding adding assets from package dependencies, see
  # https://flutter.dev/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.dev/custom-fonts/#from-packages

---

应用程序屏幕图像：

Answer 1

您在

AndroidManifest.xml

文件中定义了 API 密钥，如下所示：

<meta-data android:name="com.google.android.geo.API_KEY"
           android:value="key=AIzaSyAvQUefjL5----------------"/>

这会导致错误，因为字符串中的

key=

使 Google Maps SDK 识别出无效的 API 密钥，这就是您的地图仅显示灰屏的原因。

API 密钥应该这样定义，从字符串本身中删除

key=

：

<meta-data android:name="com.google.android.geo.API_KEY"
          android:value="AIzaSyAvQUefjL5----------------"/>

Answer 2

启用 Impeller 后，它不会在 Android 上显示

<meta-data android:name="io.flutter.embedding.android.EnableImpeller" android:value="false" />