Google Oauth Webflow Android

How can you authenticate using OAuth 2.0 with Google APIs? I have tried using the native dialog flow but that recently broken with the GoogleAuthUtil getToken() method returning d

Solution 1:

Make sure to register your application in the Google APIs Console.

Change the status to "On" for the APIs you wish to access.

google_oauth_webflow.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical"android:layout_width="fill_parent"android:layout_height="fill_parent"
        ><WebViewandroid:id="@+id/webview"android:layout_width="fill_parent"android:layout_height="fill_parent"android:layout_weight="1" /></LinearLayout>

arrays.xml

<?xml version="1.0" encoding="utf-8"?><resources><string-arrayname="scopes"><item>https://www.google.com/m8/feeds</item><item>https://www.googleapis.com/auth/userinfo.email</item><item>https://www.googleapis.com/auth/plus.login</item><item>https://www.googleapis.com/auth/userinfo.profile</item></string-array></resources>

GoogleOAuthWebFlowActivity.java

import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.view.Window;
import android.webkit.JavascriptInterface;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.ProgressBar;
import android.widget.Toast;
import com.biggu.shopsavvy.R;
import com.biggu.shopsavvy.utils.Toaster;

import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

publicclassGoogleOAuthWebFlowActivityextendsActivity {
    private WebView webview;
    privatestaticfinalStringTAG="Main";
    private ProgressBar progressBar;

    /** Called when the activity is first created. */@OverridepublicvoidonCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        requestWindowFeature(Window.FEATURE_NO_TITLE | Window.FEATURE_INDETERMINATE_PROGRESS);

        setContentView(R.layout.google_oauth_webflow);

        this.webview = (WebView)findViewById(R.id.webview);

        WebSettingssettings= webview.getSettings();
        settings.setJavaScriptEnabled(true);
        webview.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);
        webview.addJavascriptInterface(newCustomJavaScriptInterface(), "Android");

        finalAlertDialogalertDialog=newAlertDialog.Builder(this).create();

        setProgressBarIndeterminateVisibility(true);

        webview.setWebViewClient(newWebViewClient() {
            publicbooleanshouldOverrideUrlLoading(WebView view, String url) {
                Log.i(TAG, "Processing webview url click...");
                view.loadUrl(url);
                returntrue;
            }

            @OverridepublicvoidonPageFinished(WebView view, String url)  {
                Log.i(TAG, "Finished loading URL: " +url);
                setProgressBarIndeterminateVisibility(false);

                if(url.startsWith("https://accounts.google.com/o/oauth2/approval")){
                    Stringht="javascript:window.Android.retrieveExchangeCode(document.getElementsByTagName('title')[0].innerHTML);";
                    webview.loadUrl(ht);
                }
            }

            publicvoidonReceivedError(WebView view, int errorCode, String description, String failingUrl) {
                Log.e(TAG, "Error: " + description);
                Toaster.makeToast("Oh no! " + description);
                alertDialog.setTitle("Error");
                alertDialog.setMessage(description);
                alertDialog.setButton(getString(android.R.string.ok), newDialogInterface.OnClickListener() {
                    publicvoidonClick(DialogInterface dialog, int which) {
                        return;
                    }
                });
                alertDialog.show();
            }
        });

        StringwebLoginClientId= getString(R.string.client_client_id);
        Stringscope= TextUtils.join(" ", getResources().getStringArray(R.array.scopes));
        Stringredirect_uri= getString(R.string.client_redirect_uri);

        Stringurl="https://accounts.google.com/o/oauth2/auth?scope="+scope
                +"&client_id="+webLoginClientId
                +"&response_type=code&access_type=offline&approval_prompt=force&redirect_uri="+redirect_uri;

        webview.loadUrl(url);
    }

    privateclassCustomJavaScriptInterface {

        @JavascriptInterfacepublicvoidretrieveExchangeCode(String titleTag) {

            StringcodePair= titleTag.substring(titleTag.indexOf("code="), titleTag.length());
            StringcodeValue= codePair.substring(5, codePair.length());

            IntentresultIntent=newIntent();
            resultIntent.putExtra("exchangeCode", codeValue);
            setResult(Activity.RESULT_OK, resultIntent);
            finish();
        }
    }
}