android - 图形 API 在 Android 中无法正常工作

Question

我正在将 Facebook 登录集成到我的 android 应用程序中，并使用 Graph API 访问用户信息。

我遇到异常行为，当我启动未使用 Facebook 登录的应用程序，然后尝试使用 Facebook 登录时，它允许我成功登录但不允许获取用户信息(即 JSON 对象上的 NullPointerException)并且它崩溃了。

另一方面，如果我再次重新启动我已经登录的应用程序(在应用程序崩溃之前成功登录)，然后按注销按钮，然后再次登录按钮。现在奇怪的事情发生了，成功登录后我可以访问用户信息。请帮助我在第一种情况下访问用户信息。

这是我的代码:

public class Login extends Activity implements View.OnClickListener{

private LoginButton facebookLogin;
private CallbackManager callbackManager;
private AccessTokenTracker accessTokenTracker;
private AccessToken accessToken;
private Profile facebookProfile;
private ProfileTracker profileTracker;

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    FacebookSdk.sdkInitialize(this.getApplicationContext());
    setContentView(R.layout.activity_login);
    callbackManager = CallbackManager.Factory.create();

    accessTokenTracker = new AccessTokenTracker() {
        @Override
        protected void onCurrentAccessTokenChanged(
                AccessToken oldAccessToken,
                AccessToken currentAccessToken) {
            // Set the access token using
            // currentAccessToken when it's loaded or set.
        }
    };

    // If the access token is available already assign it.
    accessToken = AccessToken.getCurrentAccessToken();

    facebookProfile = Profile.getCurrentProfile();

    /*profileTracker = new ProfileTracker() {
        @Override
        protected void onCurrentProfileChanged(
                Profile oldProfile,
                Profile currentProfile) {
            // App code
        }
    };*/

    facebookLogin = (LoginButton)findViewById(R.id.button_facebookLogin_Login);
    facebookLogin.setReadPermissions(Arrays.asList("public_profile", "email"));
    facebookLogin.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
        @Override
        public void onSuccess(LoginResult loginResult) {
            facebookLogin.setReadPermissions(Arrays.asList("public_profile", "email"));
            GraphRequest request = GraphRequest.newMeRequest(accessToken,
                    new GraphRequest.GraphJSONObjectCallback(){

                        @Override
                        public void onCompleted(JSONObject object, GraphResponse response) {

                            Log.d("TOP","Object = "+object.toString());

                        }
                    });
            Bundle parameters = new Bundle();
            parameters.putString("fields", "id,name,email,gender");
            request.setParameters(parameters);
            request.executeAsync();
            // App code
        }

        @Override
        public void onCancel() {
            // App code
        }

        @Override
        public void onError(FacebookException exception) {
            // App code
        }
    });

}

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

@Override
public void onDestroy() {
    super.onDestroy();
    //accessTokenTracker.stopTracking();
    //profileTracker.stopTracking();
}

}

Answer 1

你能像我一样尝试创建Graph 请求吗:Getting email from Facebook - FB android SDK

Callback 完成后，使用 AccessToken，例如:loginResult.getAccessToken()

facebookLogin.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
    @Override
    public void onSuccess(LoginResult loginResult) {
        facebookLogin.setReadPermissions(Arrays.asList("public_profile", "email"));
        GraphRequest request = GraphRequest.newMeRequest(loginResult.getAccessToken(),
                new GraphRequest.GraphJSONObjectCallback(){

                    @Override
                    public void onCompleted(JSONObject object, GraphResponse response) {

                        Log.d("TOP","Object = "+object.toString());

                    }
                });
        Bundle parameters = new Bundle();
        parameters.putString("fields", "id,name,email,gender");
        request.setParameters(parameters);
        request.executeAsync();
        // App code
    }

如果您想查看示例 Json 格式，请尝试 Graph Api in : Graph Api Explorer

请尝试这种方式并给出结果!