How to obtain a Google Maps API Key

To use the Google Maps functionality in Android, you need to register for a Maps API key with Google. Until you do this, you will just see a blank grid instead of a map in your applications. You must obtain a Google Maps Android API v2 key - keys from the older Google Maps Android API key v1 will not work.

Obtaining a Maps API v2 key involves the following steps:

1. Retrieve the SHA-1 fingerprint of the keystore that is used to sign the application.
2. Create a project in the Google APIs console.
3. Obtaining the API key.

Obtaining your Signing Key Fingerprint

To request a Maps API key from Google, you need to know the SHA-1 fingerprint of the keystore that is used to sign the application. Typically, this means you will have to determine the SHA-1 fingerprint for the debug keystore, and then the SHA-1 fingerprint for the keystore that is used to sign your application for release.

Run keytool using the following command (using the file paths shown above):

  shell

  keytool -list -v -keystore [STORE FILENAME] -alias [KEY NAME] -storepass [STORE PASSWORD] -keypass [KEY PASSWORD]

Debug.keystore Example

For the default debug key (which is automatically created for you for debugging), use this command:

        cmd

        keytool.exe -list -v -keystore "C:\Users\[USERNAME]\AppData\Local\Xamarin\Mono for Android\debug.keystore" -alias androiddebugkey -storepass android -keypass android
      

        bash

        keytool -list -v -keystore /Users/[USERNAME]/.local/share/Xamarin/Mono\ for\ Android/debug.keystore -alias androiddebugkey -storepass android -keypass android
      

Production Keys

When deploying an app to Google Play, it must be signed with a private key. The keytool will need to be run with the private key details, and the resulting SHA-1 fingerprint used to create a production Google Maps API key. Remember to update the AndroidManifest.xml file with the correct Google Maps API key before deployment.

Keytool Output

You should see something like the following output in your console window:

  shell

  Alias name: androiddebugkey
  Creation date: Jan 01, 2016
  Entry type: PrivateKeyEntry
  Certificate chain length: 1
  Certificate[1]:
  Owner: CN=Android Debug, O=Android, C=US
  Issuer: CN=Android Debug, O=Android, C=US
  Serial number: 4aa9b300
  Valid from: Mon Jan 01 08:04:04 UTC 2013 until: Mon Jan 01 18:04:04 PST 2033
  Certificate fingerprints:
    MD5:  AE:9F:95:D0:A6:86:89:BC:A8:70:BA:34:FF:6A:AC:F9
    SHA1: BB:0D:AC:74:D3:21:E1:43:07:71:9B:62:90:AF:A1:66:6E:44:5D:75
    Signature algorithm name: SHA1withRSA
    Version: 3

You will use the SHA-1 fingerprint (listed after SHA1) later in this guide.

Creating an API project

After you have retrieved the SHA-1 fingerprint of the signing keystore, it is necessary to create a new project in the Google APIs console (or add the Google Maps Android API v2 service to an existing project).

1. In a browser, navigate to the Google Developers Console API & Services Dashboard and click Select a project. Click on a project name or create a new one by clicking NEW PROJECT:

2. If you created a new project, enter the project name in the New Project dialog that is displayed. This dialog will manufacture a unique project ID that is based on your project name. Next, click the Create button as shown in this example:

3. After a minute or so, the project is created and you are taken to the Dashboard page of the project. From there, click ENABLE APIS AND SERVICES:

4. From the API Library page, click Maps SDK for Android. On the next page, click ENABLE to turn on the service for this project:

At this point the API project has been created and Google Maps Android API v2 has been added to it. However, you cannot use this API in your project until you create credentials for it. The next section explains how to create an API key and white-list a Xamarin.Android application so that it is authorized to use this key.

Obtaining the API Key

After the Google Developer Console API project has been created, it is necessary to create an Android API key. Xamarin.Android applications must have an API key before they are granted access to Android Map API v2.

1. In the Maps SDK for Android page that is displayed (after clicking ENABLE in the previous step), go to the Credentials tab and click the Create credentials button:

2. Click API key:

3. After this button is clicked, the API key is generated. Next it is necessary to restrict this key so that only your app can call APIs with this key. Click RESTRICT KEY:

4. Change the Name field from API Key 1 to a name that will help you remember what the key is used for (XamarinMapsDemoKey is used in this example). Next, click the Android apps radio button:

5. To add the SHA-1 fingerprint, click + Add package name and fingerprint:

6. Enter your app's package name and enter the SHA-1 certificate fingerprint (obtained via keytool as explained earlier in this guide). In the following example, the package name for XamarinMapsDemo is entered, followed by the SHA-1 certificate fingerprint obtained from debug.keystore:

7. Note that, in order for your APK to access Google Maps, you must include SHA-1 fingerprints and package names for every keystore (debug and release) that you use to sign your APK. For example, if you use one computer for debug and another computer for generating the release APK, you should include the SHA-1 certificate fingerprint from the debug keystore of the first computer and the SHA-1 certificate fingerprint from the release keystore of the second computer. Click + Add package name and fingerprint to add another fingerprint and package name as shown in this example:

8. Click the Save button to save your changes. Next, you are returned to the list of your API keys. If you have other API keys that you have created earlier, they will also be listed here. In this example, only one API key (created in the previous steps) is listed: