使用Android登录获取Google OAuth令牌

Question

我已成功设置Google登录，如this article中所述。我的下一步是使用我自己的服务器来验证用户，为此我需要Google OAuth令牌。是否有可能使用此API检索令牌？

Answer 1

这就是我如何得到它的工作。当ApiClient引发UserRecoverableException时，主要警告显示权限对话框。

public class GoogleAuthenticator implements 
     GoogleApiClient.ConnectionCallbacks, 
     GoogleApiClient.OnConnectionFailedListener { 

    /* RequestCode for resolutions involving sign-in */ 
    private static final int RC_SIGN_IN = 9001; 

    /* Keys for persisting instance variables in savedInstanceState */ 
    private static final String KEY_IS_RESOLVING = "is_resolving"; 
    private static final String KEY_SHOULD_RESOLVE = "should_resolve"; 

    /* Is there a ConnectionResult resolution in progress? */ 
    private boolean mIsResolving = false; 
    /* Should we automatically resolve ConnectionResults when possible? */ 
    private boolean mShouldResolve = false; 

    private final Activity mParentActivity; 
    private final GoogleApiClient mGoogleApiClient; 

    public GoogleAuthenticator(Activity activity) { 
     mParentActivity = activity; 
     mGoogleApiClient = new GoogleApiClient.Builder(mParentActivity) 
       .addConnectionCallbacks(this) 
       .addOnConnectionFailedListener(this) 
       .addApi(Plus.API) 
       .addScope(new Scope(Scopes.PROFILE)) 
       .build(); 
    } 

    @Override 
    public void saveInstanceState(Bundle outState) { 
     outState.putBoolean(KEY_IS_RESOLVING, mIsResolving); 
     outState.putBoolean(KEY_SHOULD_RESOLVE, mShouldResolve); 
    } 

    @Override 
    public void restoreInstanceState(Bundle savedInstanceState) { 
     if (savedInstanceState != null) { 
      mIsResolving = savedInstanceState.getBoolean(KEY_IS_RESOLVING); 
      mShouldResolve = savedInstanceState.getBoolean(KEY_SHOULD_RESOLVE); 
     } 
    } 

    @Override 
    public void signIn() { 
     mShouldResolve = true; 
     mGoogleApiClient.connect(); 
    } 

    @Override 
    public void signOut() { 
     if (mGoogleApiClient.isConnected()) { 
      Plus.AccountApi.clearDefaultAccount(mGoogleApiClient); 
      mGoogleApiClient.disconnect(); 
     } 
    } 

    @Override 
    public void disconnect() { 
     if (mGoogleApiClient.isConnected()) { 
      Plus.AccountApi.clearDefaultAccount(mGoogleApiClient); 
      Plus.AccountApi.revokeAccessAndDisconnect(mGoogleApiClient); 
      mGoogleApiClient.disconnect(); 
     } 
    } 

    @Override 
    public void onActivityResult(int requestCode, int resultCode, Intent data) { 
     if (requestCode == RC_SIGN_IN) { 
      if (resultCode != Activity.RESULT_OK) { 
       mShouldResolve = false; 
      } 

      mIsResolving = false; 
      mGoogleApiClient.connect(); 
     } 
    } 

    @Override 
    public void onConnected(Bundle bundle) { 
     mShouldResolve = false; 
     new GetTokenTask(mParentActivity, mGoogleApiClient).execute(); 
    } 

    @Override 
    public void onConnectionSuspended(int i) {} 

    @Override 
    public void onConnectionFailed(ConnectionResult connectionResult) { 
     LogUtil.d(TAG, "onConnectionFailed:" + connectionResult); 

     if (!mIsResolving && mShouldResolve) { 
      if (connectionResult.hasResolution()) { 
       try { 
        connectionResult.startResolutionForResult(mParentActivity, RC_SIGN_IN); 
        mIsResolving = true; 
       } catch (IntentSender.SendIntentException e) { 
        LogUtil.e(TAG, "Could not resolve ConnectionResult.", e); 
        mIsResolving = false; 
        mGoogleApiClient.connect(); 
       } 
      } else { 
       // do something with the error 
      } 
     } else { 
      // do something when logged out 
     } 
    } 

    /** 
    * An {@link AsyncTask} to retrieve the auth token for the selected Google account 
    */ 
    private static class GetTokenTask extends AsyncTask<Void, Void, String> { 

     private final static String GOOGLE_SCOPES = "oauth2: email profile"; 
     private final Activity mActivity; 
     private final GoogleApiClient mClient; 

     private boolean needsFurtherResolution = false; 

     public GetTokenTask(Activity activity, GoogleApiClient client) { 
      mActivity = activity; 
      mClient = client; 
     } 

     @Override 
     protected String doInBackground(Void... params) { 
      needsFurtherResolution = false; 
      LogUtil.d(TAG, "Executing GetTokenTask..."); 
      final String accountName = Plus.AccountApi.getAccountName(mClient); 
      String token = null; 
      try { 
       token = GoogleAuthUtil.getToken(mActivity, accountName, GOOGLE_SCOPES, null); 
      } catch (IOException e) { 
       LogUtil.e(TAG, "Error retrieving ID token.", e); 
      } catch (UserRecoverableAuthException e) { 
       // This will show the dialog "App needs permission to access..." 
       LogUtil.d(TAG, "Launching permissions dialog"); 
       needsFurtherResolution = true; 
       mActivity.startActivityForResult(e.getIntent(), RC_SIGN_IN); 
      } catch (GoogleAuthException e) { 
       LogUtil.e(TAG, "Error retrieving ID token.", e); 
      } 
      return token; 
     } 

     @Override 
     protected void onPostExecute(String result) { 
      if (!needsFurtherResolution) { 
       // do something when token retrieved 
      } 
     } 
    } 
}