How To MAke Android Game

Step 1: Download the sample app

For this developer guide, you will need to download the Type-a-Number Challenge sample Android application.
To download and set up the sample application in Android Studio:

1. Download the Android samples from the samples download page.
2. Import the BasicSamples project. This project includes TypeANumber and other Android game samples. To do this in Android Studio:
   1. Click File > Import Project.
   2. Browse to the directory where you downloaded android-basic-samples on your development machine. Select the file android-basic-samples/BasicSamples/build.gradle and click OK.
3. In the TypeANumber module, open AndroidManifest.xml and change the package name from com.google.example.games.tanc to a different package name of your own. The new package name must not start with com.google, com.example, or com.android.

Step 2: Set up the game in the Google Play Developer Console

The Google Play Google Play Developer Console is where you manage Google Play games services for your game, and configure metadata for authorizing and authenticating your game.
To set up the sample game in the Google Play Developer Console:

1. Point your web browser to the Google Play Developer Console, and sign in. If you haven't registered for the Google Play Developer Console before, you will be prompted to do so.
2. Follow these instruction to add your game to the Google Play Developer Console.
   1. When asked if you use Google APIs in your app, select I don’t use any Google APIs in my game yet.
   2. For the purpose of this developer guide, you can fill up the form with your own game details. For convenience, you can use the placeholder icons and screenshots provided in the Downloads page.
3. Follow these instructions to generate an OAuth 2.0 client ID for your Android app.
   1. When linking your Android app, make sure to specify the exact package name you used previously when renaming sample package.
   2. You can use the Generate Signed APK Wizard in Android Studio to generate a new keystore and signed certificate if you don’t have one already. To learn how to run the Generate Signed APK Wizard, see Signing Your App in Android Studio.
4. Make sure to record the following information for later:
   1. Your application ID: This is a string consisting only of digits (typically 12 or more), at the beginning of your client ID.
   2. Your signing certificate: Note which certificate you used when setting up your API access (the certificate whose SHA1 fingerprint you provided). You should use the same certificate to sign your app when testing or releasing your app.
5. Configure achievements for Type-a-Number Challenge:
   1. Select the Achievements tab in the Google Play Developer Console.
   2. Add the following sample achievements:

      Name	Description	Special Instructions
      Prime	Get a score that's a prime number.	None
      Humble	Request a score of 0.	None
      Don't get cocky, kid	Request a score of 9999 in either mode.	None
      OMG U R TEH UBER LEET!	Receive a score of 1337.	Make this a hidden achievement.
      Bored	Play the game 10 times.	Make this an an incremental achievement with 10 steps to unlock.
      Really Really Bored	Play the game 100 times.	Make this an an incremental achievement with 100 steps to unlock.

   3. Record the IDs (long alphanumeric strings) for each achievement that you created.
   4. Configure achievements that are appropriate for your game. To learn more, see the concepts behind achievements and how to implement achievements in Android.
6. Configure the leaderboards for Type-a-Number Challenge:
   1. Select the Leaderboards tab in the Google Play Developer Console.
   2. Add two sample leaderboards: one named “Easy High Scores” and another named “Hard High Scores”. Both leaderboards should use Integer score formatting with 0 decimal places, and an ordering type of Larger is better.
   3. Record the IDs (long alphanumeric strings) for each leaderboard you created.
   4. Configure leaderboards that are appropriate for your game. To learn more, see the concepts behind leaderboards and how to implement leaderboards in Android.
7. Add test accounts for your game. This step is needed only for apps that have not yet been published in the Google Play Developer Console. Before the app is published, only the test accounts listed in the Google Play Developer Console can log in. However, once an application is published, everyone is allowed to log in.

Warning: If you try to make Play Games SDK calls for an unpublished game by using an account that's not listed as a test account, the Google Play games services will behave as if the game did not exist and you'll get back the ConnectionResult.SIGN_IN_REQUIRED return code. If you attempt to launch ConnectionResult.startResolutionForResult(), you'll get back GamesActivityResultCodes.RESULT_SIGN_IN_FAILED.

Step 3: Modify your code

To run the game, you need to configure the application ID as a resource in your Android project. You will also need to add games metadata in the AndroidManifest.xml.

1. Open res/values/ids.xml and replace the placeholder IDs. If you are creating an Android game from scratch, you will need to create this file first.
   1. Specify your application ID in the app_id resource.
   2. Specify each achievement ID that you created earlier in the corresponding achievement_* resource.
   3. Specify each leaderboard ID that you created earlier in the corresponding leaderboard_* resource.
2. Open AndroidManifest.xml and enter your package name in the package attribute of the <manifest> element. If you are creating an Android game from scratch, make sure that you also add the following code inside the <application> element:

      <meta-data android:name="com.google.android.gms.games.APP_ID"
           android:value="@string/app_id" />
      <meta-data android:name="com.google.android.gms.version"
          android:value="@integer/google_play_services_version"/>
      

Step 4: Test your game

To ensure that Google Play games services are functioning correctly in your game, test the application before you publish it on Google Play.

Note: It's recommended that you test on a physical Android device. However, if you do not have a physical device, you can test against the Android Emulator. To do so, download the emulator system image that includes the Google Play Services, under Android 4.2.2, from the SDK Manager.

To run your game on your physical test device:

1. Verify that you have set up the test account that you are using to log in to the app (as described in Step 2).
2. Export an APK and sign it with the same certificate that you used to set up the project in Google Play Developer Console. To export a signed APK in Android Studio, click Build > Generate Signed APK.
3. Install the signed APK on your physical test device by using the adb tool. To learn how to install an application, see Running on a Device.

Warning: When you run the application directly from Android Studio, Android Studio will sign the application with your debug certificate by default. If you did not use this debug certificate when setting up the application in Google Play Developer Console, this will cause errors. Make sure to run an APK that you exported and signed with a certificate that matches one of the certificates you used during the application setup in Google Play Developer Console.