android - 在 Activity 之间传递 session 信息(Facebook张贴在墙上的示例)

我正在尝试编写一个简单的2屏幕应用程序，其中第1屏幕用户通过Facebook进行身份验证，第2屏幕用户在用户墙上单击简单按钮。

当我单击PostonWall按钮时，我收到一个NullPointerException，我认为它与活动之间传递会话信息有关。但是我不知道如何还原会话信息。

我在这里做错了什么？任何建议高度赞赏！

提前致谢。

这是我的第一屏代码。

public class HelloWorldActivity extends Activity {
    /** Called when the activity is first created. */
    private static final String FACEBOOK_APPID = "XXXXXX";
    private static final String FACEBOOK_PERMISSION = "publish_stream";
    public FacebookConnector facebookConnector;
    private TextView FacebookStatus;
    private Button FacebookButton, ButtonNextScreen;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        FacebookStatus=(TextView)findViewById(R.id.textView1);
        FacebookButton=(Button)findViewById(R.id.button1);
        ButtonNextScreen=(Button)findViewById(R.id.ButtonNextScreen);

        this.facebookConnector = new FacebookConnector(FACEBOOK_APPID, this, getApplicationContext(), new String[] {FACEBOOK_PERMISSION});

        FacebookButton.setOnClickListener(new OnClickListener() {

            public void onClick(View v) {
                SessionEvents.AuthListener listener = new SessionEvents.AuthListener() {

                    @Override
                    public void onAuthSucceed() {
                        SessionStore.save(facebookConnector.getFacebook(), getApplicationContext());
                        FacebookStatus.setText("Facebook Authenticated!!");
                    }

                    @Override
                    public void onAuthFail(String error) {

                    }
                };
                SessionEvents.addAuthListener(listener);
                facebookConnector.login();
            }
        });

        ButtonNextScreen.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                // Intend to go second screen (SendScreen)
                Intent i=new Intent(v.getContext(),SecondClass.class);
                startActivity(i);
            }
        });


    }
}

/////////////// FacebookConnector方法，

public FacebookConnector(String appId,Activity activity,Context context,String[] permissions) {
        this.facebook = new Facebook(appId);

        SessionStore.restore(facebook, context);
        SessionEvents.addAuthListener(mSessionListener);
        SessionEvents.addLogoutListener(mSessionListener);

        this.context=context;
        this.permissions=permissions;
        this.mHandler = new Handler();
        this.activity=activity;
    }

//////////////会话保存和会话方法

public class SessionStore {

    private static final String TOKEN = "access_token";
    private static final String EXPIRES = "expires_in";
    private static final String KEY = "facebook-session";

    public static boolean save(Facebook session, Context context) {
        Editor editor =
            context.getSharedPreferences(KEY, Context.MODE_PRIVATE).edit();
        editor.putString(TOKEN, session.getAccessToken());
        editor.putLong(EXPIRES, session.getAccessExpires());
        return editor.commit();
    }

    public static boolean restore(Facebook session, Context context) {
        SharedPreferences savedSession =
            context.getSharedPreferences(KEY, Context.MODE_PRIVATE);
        session.setAccessToken(savedSession.getString(TOKEN, null));
        session.setAccessExpires(savedSession.getLong(EXPIRES, 0));
        return session.isSessionValid();
    }

///////////第二类

公共类SecondClass扩展Activity {

private static final String TAG = "FacebookSample";
private static final String MSG = "Message from FacebookSample";
private Button FacebookPostButton;
private FacebookConnector facebookConnector; // I THINK THIS SHOULD BE THE ISSUE
private final Handler mFacebookHandler = new Handler();

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

        FacebookPostButton=(Button)findViewById(R.id.FacebookPostButton);
        FacebookPostButton.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
        if (SessionStore.restore(facebookConnector.getFacebook(), getApplicationContext()))
                {
                    postMessageInThread();
                }
            }
        });

}

最佳答案

尝试将访问令牌保存为SharedPreferances。

像这样的东西：

                    SharedPreferences.Editor editor = mPrefs.edit();
                editor.putString("access_token", facebook.getAccessToken());

然后把它放在其他活动上