Example of using Google Signin to access Youtube subscription API

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:weightSum="4"
    tools:context=".SignInActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="3"
        android:gravity="center_horizontal"
        android:orientation="vertical">

        <ImageView
            android:id="@+id/google_icon"
            android:layout_width="48dp"
            android:layout_height="48dp"
            android:layout_marginBottom="10dp"/>

        <TextView
            android:id="@+id/title_text"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="10dp"
            android:text="title"
            android:gravity="center"
            android:textColor="@android:color/white"
            android:textSize="36sp" />

        <TextView
            android:id="@+id/status"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="signout"
            android:textColor="@android:color/white"
            android:textSize="14sp" />

        <TextView
            android:id="@+id/detail"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:fadeScrollbars="true"
            android:gravity="center"
            android:maxLines="5"
            android:padding="10dp"
            android:scrollbars="vertical"
            android:textColor="@android:color/white"
            android:textSize="14sp" />

        <Button
            android:id="@+id/button_optional_action"
            style="@style/Base.Widget.AppCompat.Button.Borderless.Colored"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:visibility="gone"
            tools:text="Optional Action"
            tools:visibility="visible" />

    </LinearLayout>


    <RelativeLayout
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight="1">

        <com.google.android.gms.common.SignInButton
            android:id="@+id/sign_in_button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:visibility="visible"
            tools:visibility="gone" />

        <LinearLayout
            android:id="@+id/sign_out_and_disconnect"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:orientation="horizontal"
            android:paddingLeft="16dp"
            android:paddingRight="16dp"
            android:visibility="gone"
            tools:visibility="visible">

            <Button
                android:id="@+id/sign_out_button"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="signout"/>

            <Button
                android:id="@+id/disconnect_button"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="disconnect" />
        </LinearLayout>

    </RelativeLayout>

</LinearLayout>

build.gradle

apply plugin: 'com.android.application'
android {

    compileSdkVersion 24
    buildToolsVersion "23.0.3"

    defaultConfig {
        applicationId "com.example.test"
        minSdkVersion 19
        targetSdkVersion 24
        versionCode 12
        versionName "1.83"
    }

    buildTypes {
        release {
            minifyEnabled true
            zipAlignEnabled true
            signingConfig signingConfigs.playStore
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

    lintOptions {
        abortOnError false
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile "com.android.support:appcompat-v7:24.2.0"
    compile 'com.android.support:design:24.2.0'
    compile 'com.android.support:recyclerview-v7:24.2.0'

    compile 'com.google.android.gms:play-services-auth:10.0.1'
    compile 'com.google.api-client:google-api-client-android:1.22.0' exclude module: 'httpclient'
    compile 'com.google.apis:google-api-services-youtube:v3-rev182-1.22.0'
}

apply plugin: 'com.google.gms.google-services'

RestApiActivity.java

package com.github.akinaru.hcidebugger.activity;

import android.accounts.Account;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

import com.github.akinaru.hcidebugger.R;
import com.google.android.gms.auth.api.Auth;
import com.google.android.gms.auth.api.signin.GoogleSignInAccount;
import com.google.android.gms.auth.api.signin.GoogleSignInOptions;
import com.google.android.gms.auth.api.signin.GoogleSignInResult;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.SignInButton;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.OptionalPendingResult;
import com.google.android.gms.common.api.ResultCallback;
import com.google.android.gms.common.api.Scope;
import com.google.android.gms.common.api.Status;
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.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.services.youtube.YouTube;
import com.google.api.services.youtube.model.Subscription;
import com.google.api.services.youtube.model.SubscriptionListResponse;

import java.io.IOException;
import java.util.Collections;
import java.util.List;

/**
 * Activity to demonstrate using the Google Sign In API with a Google API that uses the Google
 * Java Client Library rather than a Google Play services API. See {@link GetContactsTask}
 * for how to access the People API using this method.
 * <p>
 * In order to use this Activity you must enable the People API on your project. Visit the following
 * link and replace 'YOUR_PROJECT_ID' to enable the API:
 * https://console.developers.google.com/apis/api/people.googleapis.com/overview?project=YOUR_PROJECT_ID
 */
public class RestApiActivity extends AppCompatActivity implements
        GoogleApiClient.OnConnectionFailedListener,
        View.OnClickListener {

    private static final String TAG = "RestApiActivity";

    // Scope for reading user's contacts
    private static final String YOUTUBE_SCOPE = "https://www.googleapis.com/auth/youtube";

    // Bundle key for account object
    private static final String KEY_ACCOUNT = "key_account";

    // Request codes
    private static final int RC_SIGN_IN = 9001;
    private static final int RC_RECOVERABLE = 9002;

    // Global instance of the HTTP transport
    private static final HttpTransport HTTP_TRANSPORT = AndroidHttp.newCompatibleTransport();

    // Global instance of the JSON factory
    private static final JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();

    private GoogleApiClient mGoogleApiClient;

    private Account mAccount;

    private TextView mStatusTextView;
    private TextView mDetailTextView;
    private ProgressDialog mProgressDialog;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Views
        mStatusTextView = (TextView) findViewById(R.id.status);
        mDetailTextView = (TextView) findViewById(R.id.detail);

        // Button listeners
        findViewById(R.id.sign_in_button).setOnClickListener(this);
        findViewById(R.id.sign_out_button).setOnClickListener(this);

        // For this example we don't need the disconnect button
        findViewById(R.id.disconnect_button).setVisibility(View.GONE);

        // Restore instance state
        if (savedInstanceState != null) {
            mAccount = savedInstanceState.getParcelable(KEY_ACCOUNT);
        }

        // Configure sign-in to request the user's ID, email address, basic profile,
        // and readonly access to contacts.
        GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
                .requestScopes(new Scope(YOUTUBE_SCOPE))
                .requestEmail()
                .build();

        // Build a GoogleApiClient with access to the Google Sign-In API and the
        // options specified by gso.
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .enableAutoManage(this /* FragmentActivity */, this /* OnConnectionFailedListener */)
                .addApi(Auth.GOOGLE_SIGN_IN_API, gso)
                .build();

        // Show a standard Google Sign In button. If your application does not rely on Google Sign
        // In for authentication you could replace this with a "Get Google Contacts" button
        // or similar.
        SignInButton signInButton = (SignInButton) findViewById(R.id.sign_in_button);
        signInButton.setSize(SignInButton.SIZE_STANDARD);
    }

    @Override
    public void onStart() {
        super.onStart();

        OptionalPendingResult<GoogleSignInResult> opr = Auth.GoogleSignInApi.silentSignIn(mGoogleApiClient);
        if (opr.isDone()) {
            // If the user's cached credentials are valid, the OptionalPendingResult will be "done"
            // and the GoogleSignInResult will be available instantly.
            Log.d(TAG, "Got cached sign-in");
            GoogleSignInResult result = opr.get();
            handleSignInResult(result);
        } else {
            // If the user has not previously signed in on this device or the sign-in has expired,
            // this asynchronous branch will attempt to sign in the user silently.  Cross-device
            // single sign-on will occur in this branch.
            showProgressDialog();
            opr.setResultCallback(new ResultCallback<GoogleSignInResult>() {
                @Override
                public void onResult(GoogleSignInResult googleSignInResult) {
                    hideProgressDialog();
                    handleSignInResult(googleSignInResult);
                }
            });
        }
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putParcelable(KEY_ACCOUNT, mAccount);
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        // Result returned from launching the Intent from GoogleSignInApi.getSignInIntent(...);
        if (requestCode == RC_SIGN_IN) {
            GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);
            handleSignInResult(result);
        }

        // Handling a user-recoverable auth exception
        if (requestCode == RC_RECOVERABLE) {
            if (resultCode == RESULT_OK) {
                getSubscriptions();
            } else {
                Toast.makeText(this, "failed", Toast.LENGTH_SHORT).show();
            }
        }
    }

    private void signIn() {
        Intent signInIntent = Auth.GoogleSignInApi.getSignInIntent(mGoogleApiClient);
        startActivityForResult(signInIntent, RC_SIGN_IN);
    }

    private void signOut() {
        // Signing out clears the current authentication state and resets the default user,
        // this should be used to "switch users" without fully un-linking the user's google
        // account from your application.
        Auth.GoogleSignInApi.signOut(mGoogleApiClient).setResultCallback(
                new ResultCallback<Status>() {
                    @Override
                    public void onResult(@NonNull Status status) {
                        updateUI(false);
                    }
                });
    }

    private void handleSignInResult(GoogleSignInResult result) {
        Log.d(TAG, "handleSignInResult:" + result.isSuccess());
        if (result.isSuccess()) {
            // Get the account from the sign in result
            GoogleSignInAccount account = result.getSignInAccount();

            // Signed in successfully, show authenticated UI.
            mStatusTextView.setText(account.getDisplayName());
            updateUI(true);

            // Store the account from the result
            mAccount = account.getAccount();

            // Asynchronously access the People API for the account
            getSubscriptions();
        } else {
            Log.v(TAG, "fail : " + result.getStatus());
            // Clear the local account
            mAccount = null;

            // Signed out, show unauthenticated UI.
            updateUI(false);
        }
    }

    private void getSubscriptions() {
        if (mAccount == null) {
            Log.w(TAG, "getContacts: null account");
            return;
        }
        new GetSubscriptionTask().execute(mAccount);
    }

    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
        Log.w(TAG, "onConnectionFailed:" + connectionResult);
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.sign_in_button:
                signIn();
                break;
            case R.id.sign_out_button:
                signOut();
                break;
        }
    }

    private void showProgressDialog() {
        if (mProgressDialog == null) {
            mProgressDialog = new ProgressDialog(this);
            mProgressDialog.setMessage("loading");
            mProgressDialog.setIndeterminate(true);
        }

        mProgressDialog.show();
    }

    private void hideProgressDialog() {
        if (mProgressDialog != null && mProgressDialog.isShowing()) {
            mProgressDialog.hide();
        }
    }

    private void updateUI(boolean signedIn) {
        if (signedIn) {
            findViewById(R.id.sign_in_button).setVisibility(View.GONE);
            findViewById(R.id.sign_out_and_disconnect).setVisibility(View.VISIBLE);
        } else {
            mStatusTextView.setText("signout");
            mDetailTextView.setText(null);

            findViewById(R.id.sign_in_button).setVisibility(View.VISIBLE);
            findViewById(R.id.sign_out_and_disconnect).setVisibility(View.GONE);
        }
    }

    /**
     * AsyncTask that uses the credentials from Google Sign In to access Youtube subscription API.
     */
    private class GetSubscriptionTask extends AsyncTask<Account, Void, List<Subscription>> {

        @Override
        protected void onPreExecute() {
            showProgressDialog();
        }

        @Override
        protected List<Subscription> doInBackground(Account... params) {
            try {
                GoogleAccountCredential credential = GoogleAccountCredential.usingOAuth2(
                        RestApiActivity.this,
                        Collections.singleton(YOUTUBE_SCOPE));
                credential.setSelectedAccount(params[0]);

                YouTube youtube = new YouTube.Builder(HTTP_TRANSPORT, JSON_FACTORY, credential)
                        .setApplicationName("Google Sign In Quickstart")
                        .build();

                SubscriptionListResponse connectionsResponse = youtube
                        .subscriptions()
                        .list("snippet")
                        .setChannelId("UCfyuWgCPu5WneQwuLBWd7Pg")
                        .execute();

                return connectionsResponse.getItems();
            } catch (UserRecoverableAuthIOException userRecoverableException) {
                Log.w(TAG, "getSubscription:recoverable exception", userRecoverableException);
                startActivityForResult(userRecoverableException.getIntent(), RC_RECOVERABLE);
            } catch (IOException e) {
                Log.w(TAG, "getSubscription:exception", e);
            }

            return null;
        }

        @Override
        protected void onPostExecute(List<Subscription> subscriptions) {
            hideProgressDialog();

            if (subscriptions != null) {
                Log.d(TAG, "subscriptions : size=" + subscriptions.size());

                // Get names of all connections
                StringBuilder msg = new StringBuilder();
                for (int i = 0; i < subscriptions.size(); i++) {
                    Log.v(TAG, "subscription : " + subscriptions.get(i).getId());
                }
                // Display names
                mDetailTextView.setText(msg.toString());
            } else {
                Log.d(TAG, "subscriptions: null");
                mDetailTextView.setText("None");
            }
        }
    }
}

Hi,

GoogleAccountCredential.usingOAuth2 this method used to log in right, why are you using this method to get subscription SubscriptionListResponse. It looks like another time login.