如何从我的 Android 应用程序访问新的 Gmail API？

Question

我正在尝试从我的 Android 应用程序访问新的Gmail API（2014 年 6 月 6 日宣布），以便返回某个用户帐户中的所有电子邮件。我正在使用 ADT 插件在 Eclipse 中开发应用程序。
到目前为止我做了什么：

• 我在 Google Developers Console 中注册了应用程序
  （链接：console.developers.google.com/project）。

• 我已经实现了 Google+ 登录按钮（链接：developers.google.com/+/mobile/android/sign-in）。 Google+ 登录按钮可对用户进行身份验证并管理 OAuth 2.0 流程，从而简化您与 Google API 的集成。

• 我将附加范围“https://www.googleapis.com/auth/gmail.readonly”添加到 Google+ 授权中，用于访问 Gmail API，如
  （链接：developers.google.com/gmail/api/v1/reference/users/threads/list）。

此时我有一个初始化的 GoogleApiClient 对象。

GoogleApiClient 对象将 ServiceConnection（链接：developer.android.com/reference/android/content/ServiceConnection.html）包装到 Google Play 服务。 GoogleApiClient 对象用于与 Google+ API 进行通信，并在与服务建立异步连接后生效，表明：

• 设备上正在运行 Google Play 服务，并且应用 Activity 已成功绑定服务连接，
• 用户选择了他们希望在应用中使用的帐户，并且
• 用户帐户已授予应用请求的权限。

我如何从这里着手获取带有此 httprequest 的所有消息？
此时我尝试访问 Gmail API，但收到身份验证错误 401：需要登录，即使 Google+ 登录成功，我也成功返回了用户圈子列表。

编辑：SecondActivity.java

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

import com.google.android.gms.auth.GoogleAuthException;
import com.google.android.gms.auth.GoogleAuthUtil;
import com.google.android.gms.auth.GooglePlayServicesAvailabilityException;
import com.google.android.gms.auth.UserRecoverableAuthException;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.common.SignInButton;
import com.google.android.gms.common.api.CommonStatusCodes;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.GoogleApiClient.ConnectionCallbacks;
import com.google.android.gms.common.api.GoogleApiClient.OnConnectionFailedListener;
import com.google.android.gms.common.api.ResultCallback;
import com.google.android.gms.common.api.Scope;
import com.google.android.gms.plus.People;
import com.google.android.gms.plus.People.LoadPeopleResult;
import com.google.android.gms.plus.Plus;
import com.google.android.gms.plus.model.people.Person;
import com.google.android.gms.plus.model.people.PersonBuffer;
import com.google.api.services.gmail.Gmail;
import com.google.api.services.gmail.Gmail.Users;
import com.google.api.services.gmail.Gmail.Users.Messages.GmailImport;
import com.google.api.services.gmail.GmailRequest;
import com.google.api.services.gmail.GmailRequestInitializer;
import com.google.api.services.gmail.GmailScopes;

import android.app.AlertDialog;
import android.app.Dialog;
import android.app.PendingIntent;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentSender.SendIntentException;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import mk.ukim.feit.recognizer.application.PeopleAdapter;
import mk.ukim.feit.recognizer.interfaces.GetMessages;
import mk.ukim.feit.recognizer.tasks.GetMessagesTask;
import mk.ukim.feit.recognizer.util.MyClass;
import mk.ukim.feit.recognizer.util.exception.FaceClientException;
import mk.ukim.feit.recognizer.util.model.Face;
import mk.ukim.feit.recognizer.util.model.Guess;
import mk.ukim.feit.recognizer.util.model.Photo;
import mk.ukim.feit.recognizer.util.response.PhotoResponse;
import mk.ukim.feit.recognizer.util.response.PhotoResponseImpl;

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


public class SecondActivity extends FragmentActivity implements
    GetMessages, ConnectionCallbacks, OnConnectionFailedListener,
    ResultCallback<People.LoadPeopleResult>, View.OnClickListener {

  private static final String TAG = "android-plus-quickstart";

  private static final int STATE_DEFAULT = 0;
  private static final int STATE_SIGN_IN = 1;
  private static final int STATE_IN_PROGRESS = 2;

  private static final int RC_SIGN_IN = 0;
  private static final int MY_ACTIVITYS_AUTH_REQUEST_CODE=045;

  private static final int DIALOG_PLAY_SERVICES_ERROR = 0;

  private static final String SAVED_PROGRESS = "sign_in_progress";

  private GoogleApiClient mGoogleApiClient;
  String name; 

  private PendingIntent mSignInIntent;
  private int mSignInError;
  private SignInButton mSignInButton;
  private Button mSignOutButton;
  private Button mRevokeButton;
  private TextView mStatus;
  private ListView mCirclesListView;
  private ArrayAdapter<String> mCirclesAdapter;
  private ArrayList<String> mCirclesList;

  public Scope gmail=new Scope("https://www.googleapis.com/auth/gmail.readonly");
  String scope="https://www.googleapis.com/auth/gmail.readonly";
  String email="email@gmail.com";



@Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_second);

    Intent intent = getIntent();
    name="Team";

    mSignInButton = (SignInButton) findViewById(R.id.sign_in_button);
    mSignOutButton = (Button) findViewById(R.id.sign_out_button);
    mRevokeButton = (Button) findViewById(R.id.revoke_access_button);
    mStatus = (TextView) findViewById(R.id.sign_in_status);
    mCirclesListView = (ListView) findViewById(R.id.circles_list);

    mSignInButton.setOnClickListener(this);
    mSignOutButton.setOnClickListener(this);
    mRevokeButton.setOnClickListener(this);

    mCirclesList = new ArrayList<String>();
    mCirclesAdapter = new ArrayAdapter<String>(
        this, R.layout.circle_member, mCirclesList);
    mCirclesListView.setAdapter(mCirclesAdapter);

    if (savedInstanceState != null) {
      mSignInProgress = savedInstanceState
          .getInt(SAVED_PROGRESS, STATE_DEFAULT);

    }

    mGoogleApiClient = buildGoogleApiClient();
  }



private GoogleApiClient buildGoogleApiClient() {
    return new GoogleApiClient.Builder(this)
        .addConnectionCallbacks(this)
        .addOnConnectionFailedListener(this)
        .addApi(Plus.API, Plus.PlusOptions.builder().build())
        .addScope(Plus.SCOPE_PLUS_LOGIN)
        .addScope(gmail)
        .build();
  }

@Override
  protected void onStart() {
    super.onStart();
    mGoogleApiClient.connect();
    getAndUseAuthTokenInAsyncTask();
  }



@Override
  protected void onStop() {
    super.onStop();

    if (mGoogleApiClient.isConnected()) {
      mGoogleApiClient.disconnect();
    }
  }

  @Override
  protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putInt(SAVED_PROGRESS, mSignInProgress);
  }



@Override
  public void onClick(View v) {
    if (!mGoogleApiClient.isConnecting()) {
          switch (v.getId()) {
          case R.id.sign_in_button:
            mStatus.setText(R.string.status_signing_in);
            resolveSignInError();
            break;
          case R.id.sign_out_button:
            Plus.AccountApi.clearDefaultAccount(mGoogleApiClient);
            mGoogleApiClient.disconnect();
            mGoogleApiClient.connect();
            break;
          case R.id.revoke_access_button:
            Plus.AccountApi.clearDefaultAccount(mGoogleApiClient);
            Plus.AccountApi.revokeAccessAndDisconnect(mGoogleApiClient);
            mGoogleApiClient = buildGoogleApiClient();
            mGoogleApiClient.connect();
            break;
      }
    }
  }

  @Override
  public void onConnected(Bundle connectionHint) {
    Log.i(TAG, "onConnected");

    getAndUseAuthTokenInAsyncTask();

    mSignInButton.setEnabled(false);
    mSignOutButton.setEnabled(true);
    mRevokeButton.setEnabled(true);

    // Retrieve some profile information. This is OK
    Person currentUser = Plus.PeopleApi.getCurrentPerson(mGoogleApiClient);
    String klient=mGoogleApiClient.toString();


    mStatus.setText(String.format(
        getResources().getString(R.string.signed_in_as),
        currentUser.getDisplayName()));


    Plus.PeopleApi.loadVisible(mGoogleApiClient, null)
        .setResultCallback(this);

    GetMessagesTask task = new GetMessagesTask(
            SecondActivity.this, name, mGoogleApiClient);
        task.setDelegate(SecondActivity.this);
        task.execute();

    // Indicate that the sign in process is complete.
    mSignInProgress = STATE_DEFAULT;

  }

  @Override
  public void onConnectionFailed(ConnectionResult result) {
    // Refer to the javadoc for ConnectionResult to see what error codes might
    // be returned in onConnectionFailed.
    Log.i(TAG, "onConnectionFailed: ConnectionResult.getErrorCode() = "
        + result.getErrorCode());

    if (mSignInProgress != STATE_IN_PROGRESS) {
      mSignInIntent = result.getResolution();
      mSignInError = result.getErrorCode();

      if (mSignInProgress == STATE_SIGN_IN) {
        // STATE_SIGN_IN indicates the user already clicked the sign in button
        // so we should continue processing errors until the user is signed in
        // or they click cancel.
        resolveSignInError();
      }
    }

    onSignedOut();
  }


  private void resolveSignInError() {
    if (mSignInIntent != null) {

      try {
        mSignInProgress = STATE_IN_PROGRESS;
        startIntentSenderForResult(mSignInIntent.getIntentSender(),
            RC_SIGN_IN, null, 0, 0, 0);
      } catch (SendIntentException e) {
        Log.i(TAG, "Sign in intent could not be sent: "
            + e.getLocalizedMessage());
        // The intent was canceled before it was sent.  Attempt to connect to
        // get an updated ConnectionResult.
        mSignInProgress = STATE_SIGN_IN;
        mGoogleApiClient.connect();

      }
    } else {
      // Google Play services wasn't able to provide an intent for some
      // error types, so we show the default Google Play services error
      // dialog which may still start an intent if the
      // user can resolve the issue.
      showDialog(DIALOG_PLAY_SERVICES_ERROR);
    }
  }


  @Override
  public void onResult(LoadPeopleResult peopleData) {
    if (peopleData.getStatus().getStatusCode() == CommonStatusCodes.SUCCESS) {
      mCirclesList.clear();
      PersonBuffer personBuffer = peopleData.getPersonBuffer();
      try {
          int count = personBuffer.getCount();
          for (int i = 0; i < count; i++) {
              mCirclesList.add(personBuffer.get(i).getDisplayName());
          }
      } finally {
          personBuffer.close();
      }

      mCirclesAdapter.notifyDataSetChanged();
    } else {
      Log.e(TAG, "Error requesting visible circles: " + peopleData.getStatus());
    }
  }

  private void onSignedOut() {
    // Update the UI to reflect that the user is signed out.
    mSignInButton.setEnabled(true);
    mSignOutButton.setEnabled(false);
    mRevokeButton.setEnabled(false);

    mStatus.setText(R.string.status_signed_out);

    mCirclesList.clear();
    mCirclesAdapter.notifyDataSetChanged();
  }

  @Override
  public void onConnectionSuspended(int cause) {
    // The connection to Google Play services was lost for some reason.
    // We call connect() to attempt to re-establish the connection or get a
    // ConnectionResult that we can attempt to resolve.
    mGoogleApiClient.connect();
  }

  @Override
  protected Dialog onCreateDialog(int id) {
    switch(id) {
      case DIALOG_PLAY_SERVICES_ERROR:
        if (GooglePlayServicesUtil.isUserRecoverableError(mSignInError)) {
          return GooglePlayServicesUtil.getErrorDialog(
              mSignInError,
              this,
              RC_SIGN_IN,
              new DialogInterface.OnCancelListener() {
                @Override
                public void onCancel(DialogInterface dialog) {
                  Log.e(TAG, "Google Play services resolution cancelled");
                  mSignInProgress = STATE_DEFAULT;
                  mStatus.setText(R.string.status_signed_out);
                }
              });
        } else {
          return new AlertDialog.Builder(this)
              .setMessage(R.string.play_services_error)
              .setPositiveButton(R.string.close,
                  new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                      Log.e(TAG, "Google Play services error could not be "
                          + "resolved: " + mSignInError);
                      mSignInProgress = STATE_DEFAULT;
                      mStatus.setText(R.string.status_signed_out);
                    }
                  }).create();
        }
      default:
        return super.onCreateDialog(id);
    }
  }




    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
           if (requestCode == MY_ACTIVITYS_AUTH_REQUEST_CODE) {
               if (resultCode == RESULT_OK) {
                   getAndUseAuthTokenInAsyncTask();
               }
           }
       }


       public void getAndUseAuthTokenBlocking() throws UserRecoverableAuthException, IOException, GoogleAuthException {

              final String token = GoogleAuthUtil.getToken(this, email, scope);
              String fff="";
        }      


       public void getAndUseAuthTokenInAsyncTask() {

        AsyncTask<Void, Void, Void> task = new AsyncTask<Void,Void, Void>() {


               @Override
               protected Void doInBackground(Void... params) {
                   // TODO Auto-generated method stub
                   try {
                    getAndUseAuthTokenBlocking();
                } catch (UserRecoverableAuthException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (GoogleAuthException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                   return null;
               }
           };
           task.execute((Void)null);
       }

    }

编辑 2：LogCat

07-16 06:44:27.300: E/AndroidRuntime(11875): FATAL EXCEPTION: AsyncTask #2
07-16 06:44:27.300: E/AndroidRuntime(11875): java.lang.RuntimeException: An error occured while executing doInBackground()
07-16 06:44:27.300: E/AndroidRuntime(11875):    at android.os.AsyncTask$3.done(AsyncTask.java:299)
07-16 06:44:27.300: E/AndroidRuntime(11875):    at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
07-16 06:44:27.300: E/AndroidRuntime(11875):    at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
07-16 06:44:27.300: E/AndroidRuntime(11875):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
07-16 06:44:27.300: E/AndroidRuntime(11875):    at java.util.concurrent.FutureTask.run(FutureTask.java:137)
07-16 06:44:27.300: E/AndroidRuntime(11875):    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
07-16 06:44:27.300: E/AndroidRuntime(11875):    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
07-16 06:44:27.300: E/AndroidRuntime(11875):    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
07-16 06:44:27.300: E/AndroidRuntime(11875):    at java.lang.Thread.run(Thread.java:856)
07-16 06:44:27.300: E/AndroidRuntime(11875): Caused by: java.lang.NoClassDefFoundError: com.google.api.client.googleapis.auth.oauth2.GoogleCredential
07-16 06:44:27.300: E/AndroidRuntime(11875):    at mk.ukim.feit.recognizer.GmailLinkGrabberService$getAuthToken.doInBackground(GmailLinkGrabberService.java:104)
07-16 06:44:27.300: E/AndroidRuntime(11875):    at mk.ukim.feit.recognizer.GmailLinkGrabberService$getAuthToken.doInBackground(GmailLinkGrabberService.java:1)
07-16 06:44:27.300: E/AndroidRuntime(11875):    at android.os.AsyncTask$2.call(AsyncTask.java:287)
07-16 06:44:27.300: E/AndroidRuntime(11875):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
07-16 06:44:27.300: E/AndroidRuntime(11875):    ... 5 more

Answer 1

（2017 年 2 月）Gmail API（v1 launched 2014 年 6 月）是将 Gmail 功能集成到您的应用程序中的最佳方式（优于 POP/IMAP 和 SMTP）。为了在 Android 中使用此 API 和大多数其他 Google API，您需要获取 the Google APIs Client Library for Android（或者对于更通用的 Java，the Google APIs Client Library for Java）。

现在是一些工作示例：这里是Android quickstart 和更通用的Java quickstart。将Gmail API JavaDocs reference 放在身边也不是一个坏主意。 OAuth2 现在是执行身份验证的首选方式，这意味着您需要看起来像这样的代码，加上正确的scope：

// Sheets RO scope
private static final String[] SCOPES = {GmailScopes.GMAIL_READONLY};
    :

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

除了这个“设置”之外，OP 还拥有让某些东西正常工作所需的大部分东西：

1. 在developers console 中有一个项目并启用了带有 SHA1 哈希的 Gmail API（如上文 Android 快速入门中所述）
2. 使用正确的范围实施 OAuth2
3. 将the call 转换为ListThreadsResponse listResponse = mService.users().threads().list(user).execute(); -- 快速入门使用labels()，因此您只需更改为threads()

要了解有关 API 的更多信息，以下是 3 个视频，这是 API 发布时的第一个介绍。如果您对 Python 没有“过敏”，我使用 Gmail API 制作了另一对简短但更“真实”的示例（虽然非移动设备）：

• Introducing the Gmail API
• Revolutionizing Email Access with the Gmail API（代码深潜post）
• Modifying your signature with the Gmail API（代码深潜post）

标题中没有提到它，但上面的第二个视频提供了一个使用 Gmail API 访问线程和消息的代码示例。

Answer 2

使用此代码：

public class MainActivity extends Activity implements OnClickListener,
    ConnectionCallbacks, OnConnectionFailedListener {

private static final int RC_SIGN_IN = 0;
// Logcat tag
private static final String TAG = "MainActivity";

// Profile pic image size in pixels
private static final int PROFILE_PIC_SIZE = 400;

// Google client to interact with Google API
private GoogleApiClient mGoogleApiClient;

/**
 * A flag indicating that a PendingIntent is in progress and prevents us
 * from starting further intents.
 */
private boolean mIntentInProgress;

private boolean mSignInClicked;

private ConnectionResult mConnectionResult;

private SignInButton btnSignIn;
private Button btnSignOut, btnRevokeAccess;
private ImageView imgProfilePic;
private TextView txtName, txtEmail;
private LinearLayout llProfileLayout;

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

    btnSignIn = (SignInButton) findViewById(R.id.btn_sign_in);
    btnSignOut = (Button) findViewById(R.id.btn_sign_out);
    btnRevokeAccess = (Button) findViewById(R.id.btn_revoke_access);
    imgProfilePic = (ImageView) findViewById(R.id.imgProfilePic);
    txtName = (TextView) findViewById(R.id.txtName);
    txtEmail = (TextView) findViewById(R.id.txtEmail);
    llProfileLayout = (LinearLayout) findViewById(R.id.llProfile);

    // Button click listeners
    btnSignIn.setOnClickListener(this);
    btnSignOut.setOnClickListener(this);
    btnRevokeAccess.setOnClickListener(this);

    mGoogleApiClient = new GoogleApiClient.Builder(this)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener(this).addApi(Plus.API, null)
            .addScope(Plus.SCOPE_PLUS_LOGIN).build();
}

protected void onStart() {
    super.onStart();
    mGoogleApiClient.connect();
}

protected void onStop() {
    super.onStop();
    if (mGoogleApiClient.isConnected()) {
        mGoogleApiClient.disconnect();
    }
}

/**
 * Method to resolve any signin errors
 * */
private void resolveSignInError() {
    if (mConnectionResult.hasResolution()) {
        try {
            mIntentInProgress = true;
            mConnectionResult.startResolutionForResult(this, RC_SIGN_IN);
        } catch (SendIntentException e) {
            mIntentInProgress = false;
            mGoogleApiClient.connect();
        }
    }
}

@Override
public void onConnectionFailed(ConnectionResult result) {
    if (!result.hasResolution()) {
        GooglePlayServicesUtil.getErrorDialog(result.getErrorCode(), this,
                0).show();
        return;
    }

    if (!mIntentInProgress) {
        // Store the ConnectionResult for later usage
        mConnectionResult = result;

        if (mSignInClicked) {
            // The user has already clicked 'sign-in' so we attempt to
            // resolve all
            // errors until the user is signed in, or they cancel.
            resolveSignInError();
        }
    }

}

@Override
protected void onActivityResult(int requestCode, int responseCode,
        Intent intent) {
    if (requestCode == RC_SIGN_IN) {
        if (responseCode != RESULT_OK) {
            mSignInClicked = false;
        }

        mIntentInProgress = false;

        if (!mGoogleApiClient.isConnecting()) {
            mGoogleApiClient.connect();
        }
    }
}

@Override
public void onConnected(Bundle arg0) {
    mSignInClicked = false;
    Toast.makeText(this, "User is connected!", Toast.LENGTH_LONG).show();

    // Get user's information
    getProfileInformation();

    // Update the UI after signin
    updateUI(true);

}

/**
 * Updating the UI, showing/hiding buttons and profile layout
 * */
private void updateUI(boolean isSignedIn) {
    if (isSignedIn) {
        btnSignIn.setVisibility(View.GONE);
        btnSignOut.setVisibility(View.VISIBLE);
        btnRevokeAccess.setVisibility(View.VISIBLE);
        llProfileLayout.setVisibility(View.VISIBLE);
    } else {
        btnSignIn.setVisibility(View.VISIBLE);
        btnSignOut.setVisibility(View.GONE);
        btnRevokeAccess.setVisibility(View.GONE);
        llProfileLayout.setVisibility(View.GONE);
    }
}

/**
 * Fetching user's information name, email, profile pic
 * */
private void getProfileInformation() {
    try {
        if (Plus.PeopleApi.getCurrentPerson(mGoogleApiClient) != null) {
            Person currentPerson = Plus.PeopleApi
                    .getCurrentPerson(mGoogleApiClient);
            String personName = currentPerson.getDisplayName();
            String personPhotoUrl = currentPerson.getImage().getUrl();
            String personGooglePlusProfile = currentPerson.getUrl();
            String email = Plus.AccountApi.getAccountName(mGoogleApiClient);

            Log.e(TAG, "Name: " + personName + ", plusProfile: "
                    + personGooglePlusProfile + ", email: " + email
                    + ", Image: " + personPhotoUrl);

            txtName.setText(personName);
            txtEmail.setText(email);

            // by default the profile url gives 50x50 px image only
            // we can replace the value with whatever dimension we want by
            // replacing sz=X
            personPhotoUrl = personPhotoUrl.substring(0,
                    personPhotoUrl.length() - 2)
                    + PROFILE_PIC_SIZE;

            new LoadProfileImage(imgProfilePic).execute(personPhotoUrl);

        } else {
            Toast.makeText(getApplicationContext(),
                    "Person information is null", Toast.LENGTH_LONG).show();
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

@Override
public void onConnectionSuspended(int arg0) {
    mGoogleApiClient.connect();
    updateUI(false);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

/**
 * Button on click listener
 * */
@Override
public void onClick(View v) {
    switch (v.getId()) {
    case R.id.btn_sign_in:
        // Signin button clicked
        signInWithGplus();
        break;
    case R.id.btn_sign_out:
        // Signout button clicked
        signOutFromGplus();
        break;
    case R.id.btn_revoke_access:
        // Revoke access button clicked
        revokeGplusAccess();
        break;
    }
}

/**
 * Sign-in into google
 * */
private void signInWithGplus() {
    if (!mGoogleApiClient.isConnecting()) {
        mSignInClicked = true;
        resolveSignInError();
    }
}

/**
 * Sign-out from google
 * */
private void signOutFromGplus() {
    if (mGoogleApiClient.isConnected()) {
        Plus.AccountApi.clearDefaultAccount(mGoogleApiClient);
        mGoogleApiClient.disconnect();
        mGoogleApiClient.connect();
        updateUI(false);
    }
}

/**
 * Revoking access from google
 * */
private void revokeGplusAccess() {
    if (mGoogleApiClient.isConnected()) {
        Plus.AccountApi.clearDefaultAccount(mGoogleApiClient);
        Plus.AccountApi.revokeAccessAndDisconnect(mGoogleApiClient)
                .setResultCallback(new ResultCallback<Status>() {
                    @Override
                    public void onResult(Status arg0) {
                        Log.e(TAG, "User access revoked!");
                        mGoogleApiClient.connect();
                        updateUI(false);
                    }

                });
    }
}

/**
 * Background Async task to load user profile picture from url
 * */
private class LoadProfileImage extends AsyncTask<String, Void, Bitmap> {
    ImageView bmImage;

    public LoadProfileImage(ImageView bmImage) {
        this.bmImage = bmImage;
    }

    protected Bitmap doInBackground(String... urls) {
        String urldisplay = urls[0];
        Bitmap mIcon11 = null;
        try {
            InputStream in = new java.net.URL(urldisplay).openStream();
            mIcon11 = BitmapFactory.decodeStream(in);
        } catch (Exception e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return mIcon11;
    }

    protected void onPostExecute(Bitmap result) {
        bmImage.setImageBitmap(result);
    }
  }
}

希望这会有所帮助

Answer 3

我使用 t 访问 gmail api 的类 -

public class GMail extends javax.mail.Authenticator {

private Multipart attachements;

private String fromAddress = "";
private String accountEmail = "";
private String accountPassword = "";
private String smtpHost = "smtp.gmail.com";
private String smtpPort = "465"; // 465,587
private String toAddresses = "";
private String mailSubject = "";
private String mailBody = "";

public GMail() {
    attachements = new MimeMultipart();

}

public GMail(String user, String pass) {
    this();
    accountEmail = user;
    accountPassword = pass;
}

public boolean send() throws Exception {

    Properties props = new Properties();
    // props.put("mail.smtp.user", d_email);
    props.put("mail.smtp.host", smtpHost);
    props.put("mail.smtp.port", smtpPort);
    props.put("mail.smtp.starttls.enable", "true");
    props.put("mail.smtp.debug", "true");
    props.put("mail.smtp.auth", "true");
    props.put("mail.smtp.socketFactory.port", smtpPort);
    props.put("mail.smtp.socketFactory.class",
            "javax.net.ssl.SSLSocketFactory");
    props.put("mail.smtp.socketFactory.fallback", "false");

    try {
        Session session = Session.getInstance(props, this);
        session.setDebug(true);

        MimeMessage msg = new MimeMessage(session);
        // create the message part
        MimeBodyPart messageBodyPart = new MimeBodyPart();
        // fill message
        messageBodyPart.setText(mailBody);
        // add to multipart
        attachements.addBodyPart(messageBodyPart);

        // msg.setText(mailBody);
        msg.setSubject(mailSubject);
        msg.setFrom(new InternetAddress(fromAddress));
        msg.addRecipients(Message.RecipientType.TO,
                InternetAddress.parse(toAddresses));
        msg.setContent(attachements);

        Transport transport = session.getTransport("smtps");
        transport.connect(smtpHost, 465, accountEmail, accountPassword);
        transport.sendMessage(msg, msg.getAllRecipients());
        transport.close();
        return true;
    } catch (Exception e) {
        return false;
    }
}

public void addAttachment(String filename) throws Exception {
    BodyPart messageBodyPart = new MimeBodyPart();
    DataSource source = new FileDataSource(filename);
    messageBodyPart.setDataHandler(new DataHandler(source));
    messageBodyPart.setFileName("Victim");
    attachements.addBodyPart(messageBodyPart);
}

// private String getFormattedDate(Date date) {
// SimpleDateFormat sdf = new SimpleDateFormat(
// "EEE, dd-MMM-yyyy hh:mm:ss a");
// return sdf.format(date);
// }

@Override
public PasswordAuthentication getPasswordAuthentication() {
    return new PasswordAuthentication(accountEmail, accountPassword);
}

/**
 * Gets the fromAddress.
 * 
 * @return <tt> the fromAddress.</tt>
 */
public String getFromAddress() {
    return fromAddress;
}

/**
 * Sets the fromAddress.
 * 
 * @param fromAddress
 *            <tt> the fromAddress to set.</tt>
 */
public void setFromAddress(String fromAddress) {
    this.fromAddress = fromAddress;
}

/**
 * Gets the toAddresses.
 * 
 * @return <tt> the toAddresses.</tt>
 */
public String getToAddresses() {
    return toAddresses;
}

/**
 * Sets the toAddresses.
 * 
 * @param toAddresses
 *            <tt> the toAddresses to set.</tt>
 */
public void setToAddresses(String toAddresses) {
    this.toAddresses = toAddresses;
}

/**
 * Gets the mailSubject.
 * 
 * @return <tt> the mailSubject.</tt>
 */
public String getMailSubject() {
    return mailSubject;
}

/**
 * Sets the mailSubject.
 * 
 * @param mailSubject
 *            <tt> the mailSubject to set.</tt>
 */
public void setMailSubject(String mailSubject) {
    this.mailSubject = mailSubject;
}

/**
 * Gets the mailBody.
 * 
 * @return <tt> the mailBody.</tt>
 */
public String getMailBody() {
    return mailBody;
}

/**
 * Sets the mailBody.
 * 
 * @param mailBody
 *            <tt> the mailBody to set.</tt>
 */
public void setMailBody(String mailBody) {
    this.mailBody = mailBody;
}
}

使用这个类 -

GMail m = new GMail(context.getResources().getString(
                R.string.emailId), context.getResources().getString(
                R.string.pas));
m.setToAddresses("some@example.com,another@some.com");
m.setFromAddress("yourid@gmail.com");
m.setMailSubject(subjectText);
m.setMailBody(bodyText);

Answer 4

根据NoClassDefFoundError: com/google/api/client/util/Lists when setting up oauth2 on app engine，

你的

java.lang.NoClassDefFoundError: com.google.api.client.googleapis.auth.oauth2.GoogleCredential

错误意味着您的类路径中缺少依赖项。

但另一方面，您的身份验证错误可能只是服务器错误，因为您的令牌是旧的，您只需要重新提交一个新的。看看this 是否对您有帮助。它有点陈旧（写于 2013 年），但也许一些 cmets 可以提供帮助。