我正在尝试从我的 Android 应用程序访问新的Gmail API（2014 年 6 月 25 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 中注册了该应用程序
（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 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程序中使用的帐户，并且
- 用户的帐户已授予应用程序请求的权限。
我如何从这里开始使用这个httprequest获取所有消息？
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