Android Quickstart

Complete the steps described in the rest of this page, and in about ten minutes you'll have a simple Android application that makes requests to the Drive API.

Prerequisites

To run this quickstart, you'll need:

  • Android Studio SDK 1.2 or later.
  • Android SDK packages for API 23 or later, including the latest versions of Google Repository, Android Support Library and Google Play Services.
  • Access to the internet on your test device.
  • A Google account with Google Drive enabled.

This quickstart will assume you are using the Android Studio IDE (as opposed to the stand-alone SDK Tools) and are comfortable finding, creating and editing files within a Studio project.

Step 1: Acquire a SHA1 fingerprint

In a terminal, run the folowing Keytool utility command to get the SHA1 fingerprint you will use to enable the API.

keytool -exportcert -alias androiddebugkey -keystore ~/.android/debug.keystore -list -v

When asked for a keystore password, enter "android".

The Keytool prints the fingerprint to the shell. For example:

$ keytool -exportcert -alias androiddebugkey -keystore ~/.android/debug.keystore -list -v
Enter keystore password: Type "android" if using debug.keystore
Alias name: androiddebugkey
Creation date: Dec 4, 2014
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: 503bd581
Valid from: Mon Aug 27 13:16:01 PDT 2012 until: Wed Aug 20 13:16:01 PDT 2042
Certificate fingerprints:
   MD5:  1B:2B:2D:37:E1:CE:06:8B:A0:F0:73:05:3C:A3:63:DD
   SHA1: D8:AA:43:97:59:EE:C5:95:26:6A:07:EE:1C:37:8E:F4:F0:C8:05:C8
   SHA256: F3:6F:98:51:9A:DF:C3:15:4E:48:4B:0F:91:E3:3C:6A:A0:97:DC:0A:3F:B2:D2:E1:FE:23:57:F5:EB:AC:13:30
   Signature algorithm name: SHA1withRSA
   Version: 3

Copy the SHA1 fingerprint, which is highlighted in the example above.

Step 2: Turn on the Drive API

  1. Use this wizard to create or select a project in the Google Developers Console and automatically turn on the API. Click Continue, then Go to credentials.
  2. On the Add credentials to your project page, click the Cancel button.
  3. At the top of the page, select the OAuth consent screen tab. Select an Email address, enter a Product name if not already set, and click the Save button.
  4. Select the Credentials tab, click the Create credentials button and select OAuth client ID.
  5. Select the application type Android.
  6. Copy the SHA1 fingerprint from Step 1 into the Signing-certificate fingerprint field.
  7. In the Package name field, enter com.example.quickstart.
  8. Click the Create button.

Step 3: Create a new Android project

  1. Open Android Studio, and start a New Android Studio Project.
  2. In the New Project screen, name the application "Quickstart".
  3. Set Company Domain to "example.com" and verify that the package name automatically produced matches the one you entered into the Developer Console in Step 2. Click Next.
  4. In the Target Android Devices screen, check the Phone and Tablet checkbox and choose a Minimum SDK of "API 11: Android 3.0 (Honeycomb)". Leave the other checkboxes unchecked. Click Next.
  5. In the Add an activity to Mobile screen, click Add No Activity.
  6. Click Finish.

At this point Android Studio will create and open the project.

Step 4: Prepare the project

In the Project sidebar you will see an expandable list of the default project files Android Studio has created. One of these is the "build.gradle" file associated with the "app" module (not the project).

  1. Open the app build.gradle file and replace its contents with the following:
  2. In the toolbar, select Tools > Android > Sync Project with Gradle Files. This will acquire and make available the libraries your project needs.
  3. Find and open the default src/main/AndroidManifest.xml file and replace its contents with the following code:
    <?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.example.quickstart">
    
        <uses-permission android:name="android.permission.INTERNET" />
        <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
        <uses-permission android:name="android.permission.GET_ACCOUNTS" />
    
        <application
            android:allowBackup="true"
            android:icon="@mipmap/ic_launcher"
            android:label="Drive API Android Quickstart"
            android:theme="@style/AppTheme" >
            <activity
                android:name=".MainActivity"
                android:label="Drive API Android Quickstart" >
                <intent-filter>
                    <action android:name="android.intent.action.MAIN" />
                    <category android:name="android.intent.category.LAUNCHER" />
                </intent-filter>
            </activity>
    
        </application>
    </manifest>
    

Step 5: Setup the sample

Create a new Java class called "MainActivity" and replace the contents of the new file with the following code.

package com.example.quickstart;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GoogleApiAvailability;
import com.google.api.client.extensions.android.http.AndroidHttp;
import com.google.api.client.googleapis.extensions.android.gms.auth.GoogleAccountCredential;
import com.google.api.client.googleapis.extensions.android.gms.auth.GooglePlayServicesAvailabilityIOException;
import com.google.api.client.googleapis.extensions.android.gms.auth.UserRecoverableAuthIOException;

import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.client.util.ExponentialBackOff;

import com.google.api.services.drive.DriveScopes;

import com.google.api.services.drive.model.*;

import android.Manifest;
import android.accounts.AccountManager;
import android.app.Activity;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.text.TextUtils;
import android.text.method.ScrollingMovementMethod;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import pub.devrel.easypermissions.AfterPermissionGranted;
import pub.devrel.easypermissions.EasyPermissions;

public class MainActivity extends Activity
    implements EasyPermissions.PermissionCallbacks {
    GoogleAccountCredential mCredential;
    private TextView mOutputText;
    private Button mCallApiButton;
    ProgressDialog mProgress;

    static final int REQUEST_ACCOUNT_PICKER = 1000;
    static final int REQUEST_AUTHORIZATION = 1001;
    static final int REQUEST_GOOGLE_PLAY_SERVICES = 1002;
    static final int REQUEST_PERMISSION_GET_ACCOUNTS = 1003;

    private static final String BUTTON_TEXT = "Call Drive API";
    private static final String PREF_ACCOUNT_NAME = "accountName";
    private static final String[] SCOPES = { DriveScopes.DRIVE_METADATA_READONLY };

    /**
     * Create the main activity.
     * @param savedInstanceState previously saved instance data.
     */
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        LinearLayout activityLayout = new LinearLayout(this);
        LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
                LinearLayout.LayoutParams.MATCH_PARENT,
                LinearLayout.LayoutParams.MATCH_PARENT);
        activityLayout.setLayoutParams(lp);
        activityLayout.setOrientation(LinearLayout.VERTICAL);
        activityLayout.setPadding(16, 16, 16, 16);

        ViewGroup.LayoutParams tlp = new ViewGroup.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT);

        mCallApiButton = new Button(this);
        mCallApiButton.setText(BUTTON_TEXT);
        mCallApiButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mCallApiButton.setEnabled(false);
                mOutputText.setText("");
                getResultsFromApi();
                mCallApiButton.setEnabled(true);
            }
        });
        activityLayout.addView(mCallApiButton);

        mOutputText = new TextView(this);
        mOutputText.setLayoutParams(tlp);
        mOutputText.setPadding(16, 16, 16, 16);
        mOutputText.setVerticalScrollBarEnabled(true);
        mOutputText.setMovementMethod(new ScrollingMovementMethod());
        mOutputText.setText(
                "Click the \'" + BUTTON_TEXT +"\' button to test the API.");
        activityLayout.addView(mOutputText);

        mProgress = new ProgressDialog(this);
        mProgress.setMessage("Calling Drive API ...");

        setContentView(activityLayout);

        // Initialize credentials and service object.
        mCredential = GoogleAccountCredential.usingOAuth2(
                getApplicationContext(), Arrays.asList(SCOPES))
                .setBackOff(new ExponentialBackOff());
    }

    

    /**
     * Attempt to call the API, after verifying that all the preconditions are
     * satisfied. The preconditions are: Google Play Services installed, an
     * account was selected and the device currently has online access. If any
     * of the preconditions are not satisfied, the app will prompt the user as
     * appropriate.
     */
    private void getResultsFromApi() {
        if (! isGooglePlayServicesAvailable()) {
            acquireGooglePlayServices();
        } else if (mCredential.getSelectedAccountName() == null) {
            chooseAccount();
        } else if (! isDeviceOnline()) {
            mOutputText.setText("No network connection available.");
        } else {
            new MakeRequestTask(mCredential).execute();
        }
    }

    /**
     * Attempts to set the account used with the API credentials. If an account
     * name was previously saved it will use that one; otherwise an account
     * picker dialog will be shown to the user. Note that the setting the
     * account to use with the credentials object requires the app to have the
     * GET_ACCOUNTS permission, which is requested here if it is not already
     * present. The AfterPermissionGranted annotation indicates that this
     * function will be rerun automatically whenever the GET_ACCOUNTS permission
     * is granted.
     */
    @AfterPermissionGranted(REQUEST_PERMISSION_GET_ACCOUNTS)
    private void chooseAccount() {
        if (EasyPermissions.hasPermissions(
                this, Manifest.permission.GET_ACCOUNTS)) {
            String accountName = getPreferences(Context.MODE_PRIVATE)
                    .getString(PREF_ACCOUNT_NAME, null);
            if (accountName != null) {
                mCredential.setSelectedAccountName(accountName);
                getResultsFromApi();
            } else {
                // Start a dialog from which the user can choose an account
                startActivityForResult(
                        mCredential.newChooseAccountIntent(),
                        REQUEST_ACCOUNT_PICKER);
            }
        } else {
            // Request the GET_ACCOUNTS permission via a user dialog
            EasyPermissions.requestPermissions(
                    this,
                    "This app needs to access your Google account (via Contacts).",
                    REQUEST_PERMISSION_GET_ACCOUNTS,
                    Manifest.permission.GET_ACCOUNTS);
        }
    }

    /**
     * Called when an activity launched here (specifically, AccountPicker
     * and authorization) exits, giving you the requestCode you started it with,
     * the resultCode it returned, and any additional data from it.
     * @param requestCode code indicating which activity result is incoming.
     * @param resultCode code indicating the result of the incoming
     *     activity result.
     * @param data Intent (containing result data) returned by incoming
     *     activity result.
     */
    @Override
    protected void onActivityResult(
            int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch(requestCode) {
            case REQUEST_GOOGLE_PLAY_SERVICES:
                if (resultCode != RESULT_OK) {
                    mOutputText.setText(
                            "This app requires Google Play Services. Please install " +
                            "Google Play Services on your device and relaunch this app.");
                } else {
                    getResultsFromApi();
                }
                break;
            case REQUEST_ACCOUNT_PICKER:
                if (resultCode == RESULT_OK && data != null &&
                        data.getExtras() != null) {
                    String accountName =
                            data.getStringExtra(AccountManager.KEY_ACCOUNT_NAME);
                    if (accountName != null) {
                        SharedPreferences settings =
                                getPreferences(Context.MODE_PRIVATE);
                        SharedPreferences.Editor editor = settings.edit();
                        editor.putString(PREF_ACCOUNT_NAME, accountName);
                        editor.apply();
                        mCredential.setSelectedAccountName(accountName);
                        getResultsFromApi();
                    }
                }
                break;
            case REQUEST_AUTHORIZATION:
                if (resultCode == RESULT_OK) {
                    getResultsFromApi();
                }
                break;
        }
    }

    /**
     * Respond to requests for permissions at runtime for API 23 and above.
     * @param requestCode The request code passed in
     *     requestPermissions(android.app.Activity, String, int, String[])
     * @param permissions The requested permissions. Never null.
     * @param grantResults The grant results for the corresponding permissions
     *     which is either PERMISSION_GRANTED or PERMISSION_DENIED. Never null.
     */
    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           @NonNull String[] permissions,
                                           @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        EasyPermissions.onRequestPermissionsResult(
                requestCode, permissions, grantResults, this);
    }

    /**
     * Callback for when a permission is granted using the EasyPermissions
     * library.
     * @param requestCode The request code associated with the requested
     *         permission
     * @param list The requested permission list. Never null.
     */
    @Override
    public void onPermissionsGranted(int requestCode, List<String> list) {
        // Do nothing.
    }

    /**
     * Callback for when a permission is denied using the EasyPermissions
     * library.
     * @param requestCode The request code associated with the requested
     *         permission
     * @param list The requested permission list. Never null.
     */
    @Override
    public void onPermissionsDenied(int requestCode, List<String> list) {
        // Do nothing.
    }

    /**
     * Checks whether the device currently has a network connection.
     * @return true if the device has a network connection, false otherwise.
     */
    private boolean isDeviceOnline() {
        ConnectivityManager connMgr =
                (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
        return (networkInfo != null && networkInfo.isConnected());
    }

    /**
     * Check that Google Play services APK is installed and up to date.
     * @return true if Google Play Services is available and up to
     *     date on this device; false otherwise.
     */
    private boolean isGooglePlayServicesAvailable() {
        GoogleApiAvailability apiAvailability =
                GoogleApiAvailability.getInstance();
        final int connectionStatusCode =
                apiAvailability.isGooglePlayServicesAvailable(this);
        return connectionStatusCode == ConnectionResult.SUCCESS;
    }

    /**
     * Attempt to resolve a missing, out-of-date, invalid or disabled Google
     * Play Services installation via a user dialog, if possible.
     */
    private void acquireGooglePlayServices() {
        GoogleApiAvailability apiAvailability =
                GoogleApiAvailability.getInstance();
        final int connectionStatusCode =
                apiAvailability.isGooglePlayServicesAvailable(this);
        if (apiAvailability.isUserResolvableError(connectionStatusCode)) {
            showGooglePlayServicesAvailabilityErrorDialog(connectionStatusCode);
        }
    }


    /**
     * Display an error dialog showing that Google Play Services is missing
     * or out of date.
     * @param connectionStatusCode code describing the presence (or lack of)
     *     Google Play Services on this device.
     */
    void showGooglePlayServicesAvailabilityErrorDialog(
            final int connectionStatusCode) {
        GoogleApiAvailability apiAvailability = GoogleApiAvailability.getInstance();
        Dialog dialog = apiAvailability.getErrorDialog(
                MainActivity.this,
                connectionStatusCode,
                REQUEST_GOOGLE_PLAY_SERVICES);
        dialog.show();
    }

    /**
     * An asynchronous task that handles the Drive API call.
     * Placing the API calls in their own task ensures the UI stays responsive.
     */
    private class MakeRequestTask extends AsyncTask<Void, Void, List<String>> {
        private com.google.api.services.drive.Drive mService = null;
        private Exception mLastError = null;

        MakeRequestTask(GoogleAccountCredential credential) {
            HttpTransport transport = AndroidHttp.newCompatibleTransport();
            JsonFactory jsonFactory = JacksonFactory.getDefaultInstance();
            mService = new com.google.api.services.drive.Drive.Builder(
                    transport, jsonFactory, credential)
                    .setApplicationName("Drive API Android Quickstart")
                    .build();
        }

        /**
         * Background task to call Drive API.
         * @param params no parameters needed for this task.
         */
        @Override
        protected List<String> doInBackground(Void... params) {
            try {
                return getDataFromApi();
            } catch (Exception e) {
                mLastError = e;
                cancel(true);
                return null;
            }
        }

        /**
         * Fetch a list of up to 10 file names and IDs.
         * @return List of Strings describing files, or an empty list if no files
         *         found.
         * @throws IOException
         */
        private List<String> getDataFromApi() throws IOException {
            // Get a list of up to 10 files.
            List<String> fileInfo = new ArrayList<String>();
            FileList result = mService.files().list()
                 .setPageSize(10)
                 .setFields("nextPageToken, files(id, name)")
                 .execute();
            List<File> files = result.getFiles();
            if (files != null) {
                for (File file : files) {
                    fileInfo.add(String.format("%s (%s)\n",
                            file.getName(), file.getId()));
                }
            }
            return fileInfo;
        }


        @Override
        protected void onPreExecute() {
            mOutputText.setText("");
            mProgress.show();
        }

        @Override
        protected void onPostExecute(List<String> output) {
            mProgress.hide();
            if (output == null || output.size() == 0) {
                mOutputText.setText("No results returned.");
            } else {
                output.add(0, "Data retrieved using the Drive API:");
                mOutputText.setText(TextUtils.join("\n", output));
            }
        }

        @Override
        protected void onCancelled() {
            mProgress.hide();
            if (mLastError != null) {
                if (mLastError instanceof GooglePlayServicesAvailabilityIOException) {
                    showGooglePlayServicesAvailabilityErrorDialog(
                            ((GooglePlayServicesAvailabilityIOException) mLastError)
                                    .getConnectionStatusCode());
                } else if (mLastError instanceof UserRecoverableAuthIOException) {
                    startActivityForResult(
                            ((UserRecoverableAuthIOException) mLastError).getIntent(),
                            MainActivity.REQUEST_AUTHORIZATION);
                } else {
                    mOutputText.setText("The following error occurred:\n"
                            + mLastError.getMessage());
                }
            } else {
                mOutputText.setText("Request cancelled.");
            }
        }
    }
}

Step 6: Run the app

  1. You can test the app by clicking the Run > Run app menu item.
  2. You will be prompted to select a connected device (recommended) or emulation to run the app on. If you choose to run on an emulation, make sure it is configured to use one of the with Google APIs system images. If you attempt to run the quickstart on a device that does not currently have Google Play services installed, the quickstart will produce a dialog from which you can install it.
  3. If running on an emulator, allow it to fully start and establish its network connection.
  4. If starting the emulator for the first time, you may need to unlock its screen. Regardless, the quickstart app should start automatically.
  5. The first time you run the app it will prompt you to specify an account. Select one of the ones suggested or select Add account and follow the instruction prompts to choose an account to connect to.
  6. After selecting an account, the app will prompt you to authorize access. Click OK to authorize.

Notes

  • Authorization information is stored with the app, so subsequent executions will not prompt for authorization.

Further reading

Troubleshooting

Unregistered Android application

When the OAuth dialog contains an entry that reads "Unregistered Android application" it means that the OAuth2 client ID you created in Step 2 cannot be found and Android is falling back to a default client. The default client won't be configured to use this API, so requests will fail with errors like accessNotConfigured or mention the default project number 608941808256.

To fix the issue, make sure the SHA1 fingerprint you retrieved in Step 1 and the applicationId listed in your build.gradle file match exactly with the values you set in the Google Developers console.

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