Google Maps Activity V2 Android Studio

我在将Google Maps API v2集成到我的应用程序时遇到了麻烦。

我正在使用Android Studio。我创建了一个新的地图活动，并遵循google_maps_api.xml：

<resources>
    <string name="google_maps_key_instructions">
    <!--
    TODO: Before you run your application, you need a Google Maps API key.

    To get one, follow this link, follow the directions and press "Create" at the end:

https://console.developers.google.com/flows/enableapi?apiid=maps_android_backend&keyType=CLIENT_SIDE_ANDROID&r=XXXXhashXXX%3Bat.schickermueller.taxameter.activity

    You can also add your credentials to an existing key, using this line:    
    XXXXhashXXX;at.schickermueller.taxameter.activity

    Once you have your key (it starts with "AIza"), replace the "google_maps_key"
    string in this file.
    -->
    </string>
    <string name="google_maps_key" templateMergeStrategy="preserve">AIzaXXXXXXXXXXXXXXXXXXXXX</string>
</resources>

我还激活了Android maps v2 API：

但是活动显示空白地图，并且出现以下错误：

08-23 12：30：45.845 11659-11829 / at.schickermueller.taxameter E / Google Maps Android API：无法加载地图。与Google服务器联系时出错。这可能是身份验证问题（但可能是由于网络错误）。

我已经尝试过一些在堆栈溢出线程中发布的“解决方案”（例如Android-Google Maps Api v2-身份验证错误）

我的清单包含以下内容：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="at.schickermueller.taxameter" >

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".activity.StartActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <service
            android:name=".service.TrackService"
            android:enabled="true"
            android:exported="true" >
        </service>

        <activity
            android:name=".activity.DriveListActivity"
            android:label="@string/title_activity_drive_list" >
        </activity>
        <activity
            android:name=".activity.DriveDetailActivity"
            android:label="@string/title_activity_drive_detail"
            android:theme="@style/Theme.AppCompat" >
        </activity>

        <meta-data
            android:name="com.google.android.gms.version"
            android:value="@integer/google_play_services_version" />
        <meta-data
            android:name="com.google.android.maps.v2.API_KEY"
            android:value="@string/google_maps_key" />

        <activity
            android:name=".activity.MapsActivity2"
            android:label="@string/title_activity_maps_activity2" >
        </activity>
    </application>

    <permission
        android:name="at.schickermueller.taxameter.permission.MAPS_RECEIVE"
        android:protectionLevel="signature" />

    <uses-feature
        android:glEsVersion="0x00020000"
        android:required="true" />

    <uses-permission android:name="at.schickermueller.taxameter.activity.permission.MAPS_RECEIVE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <!--
         The ACCESS_COARSE/FINE_LOCATION permissions are not required to use
         Google Maps Android API v2, but are recommended.
    -->
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

</manifest>

我希望你能帮帮我