Question

尝试在其他屏幕中访问Facebook会话所以尝试Session.getActiveSession但是它返回null，所以尝试使用缓存如下

if (session == null) {
    // try to restore from cache
    session = Session
              .openActiveSessionFromCache(getApplicationContext());
}

if (session != null && session.isOpened()) {
    // Start a background task which handles ntwork calls
    new FetchTask().execute();
}

但随后也出现以下错误，建议我选择合适的解决方案，谢谢这是堆栈跟踪

 01-21 20:28:03.431: E/AndroidRuntime(28191): FATAL EXCEPTION: main
01-21 20:28:03.431: E/AndroidRuntime(28191): java.lang.NullPointerException: Argument '148885915321893' cannot be null
01-21 20:28:03.431: E/AndroidRuntime(28191):    at com.facebook.internal.Validate.notNull(Validate.java:29)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at com.facebook.Session.<init>(Session.java:227)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at com.facebook.Session.<init>(Session.java:216)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at com.facebook.Session$Builder.build(Session.java:1576)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at com.facebook.Session.openActiveSession(Session.java:888)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at com.facebook.Session.openActiveSessionFromCache(Session.java:808)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at com.srikanth.ema.Transaction$HttpAsyncTask.onPostExecute(Transaction.java:172)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at com.srikanth.ema.Transaction$HttpAsyncTask.onPostExecute(Transaction.java:1)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at android.os.AsyncTask.finish(AsyncTask.java:631)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at android.os.AsyncTask.access$600(AsyncTask.java:177)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at android.os.Handler.dispatchMessage(Handler.java:99)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at android.os.Looper.loop(Looper.java:137)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at android.app.ActivityThread.main(ActivityThread.java:4960)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at java.lang.reflect.Method.invokeNative(Native Method)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at java.lang.reflect.Method.invoke(Method.java:511)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
01-21 20:28:03.431: E/AndroidRuntime(28191):    at dalvik.system.NativeStart.main(Native Method)

Answer 1

您可以创建这样的方法

private Session createSession() {
    Session activeSession = Session.getActiveSession();
    if (activeSession == null || activeSession.getState().isClosed()) {
        activeSession = new Session.Builder(mainActivity).setApplicationId(appId).build();
        Session.setActiveSession(activeSession);
    }
    return activeSession;
}

然后在构造函数中：

this.session = createSession();

然后阅读内容

public void obtainFBInfo(){
    if (this.session.isOpened()) {
        getID();
    } else {
        StatusCallback callback = new StatusCallback() {
            public void call(Session session, SessionState state, Exception exception) {
                if (exception != null) {
                    ConnectToFacebook.this.session = createSession();
                }
                else if(state == SessionState.OPENED || state == SessionState.OPENED_TOKEN_UPDATED)
                    getID();
            }
        };
        this.session.openForRead(new Session.OpenRequest(mainActivity).setCallback(callback));
    }
}

确保在您的活动中有这个：

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if(Session.getActiveSession() != null){
        Session.getActiveSession().onActivityResult(this, requestCode, resultCode, data);
    }
}

以下是全班：

import android.app.Activity;
import android.os.Bundle;

import com.facebook.FacebookRequestError;
import com.facebook.LoggingBehavior;
import com.facebook.Request;
import com.facebook.Response;
import com.facebook.Session;
import com.facebook.Session.StatusCallback;
import com.facebook.SessionState;
import com.facebook.Settings;
import com.facebook.model.GraphObject;

public class ConnectToFacebook {

static final String appId = "your app ID";
private Session session;
private Activity mainActivity;

/**
 * 
 */
public ConnectToFacebook(Activity mainActivity) {
    this.mainActivity = mainActivity;
    this.session = createSession();
    Settings.addLoggingBehavior(LoggingBehavior.INCLUDE_ACCESS_TOKENS);
}

public void obtainFBInfo(){
    if (this.session.isOpened()) {
        getID();
    } else {
        StatusCallback callback = new StatusCallback() {
            public void call(Session session, SessionState state, Exception exception) {
                if (exception != null) {

                    ConnectToFacebook.this.session = createSession();
                }
                else if(state == SessionState.OPENED || state == SessionState.OPENED_TOKEN_UPDATED)
                    getID();
            }
        };
        this.session.openForRead(new Session.OpenRequest(mainActivity).setCallback(callback));
    }
}

private void getID() {
    new Thread(new Runnable() {

        @Override
        public void run() {
            String requestIdsText = "me";
            Bundle params = new Bundle();
            params.putString("fields", "id,name,installed");
            new Request(session, requestIdsText, params, null, new Request.Callback() {
                public void onCompleted(Response response) {
                    GraphObject graphObject = response.getGraphObject();
                    FacebookRequestError error = response.getError();
                    if (graphObject != null) {
                        if (graphObject.getProperty("id") != null) 
                            //setFbId(String.format("%s", graphObject.getProperty("id")));
                        if (graphObject.getProperty("name") != null) 
                            //setFbName(String.format("%s", graphObject.getProperty("name")));
                        if(mainActivity instanceof ScreenOptions)
                            ((ScreenOptions) mainActivity).runOnUiThread(new Runnable() {
                                @Override
                                public void run() {
                                    ((ScreenOptions) mainActivity).updateConnectionStatus();
                                }
                            });

                    } else if (error != null) {
                        System.err.println(String.format("Error: %s", error.getErrorMessage()));
                    }
                }
            }).executeAndWait();
        }
    }).start();

}

private Session createSession() {
    Session activeSession = Session.getActiveSession();
    if (activeSession == null || activeSession.getState().isClosed()) {
        activeSession = new Session.Builder(mainActivity).setApplicationId(appId).build();
        Session.setActiveSession(activeSession);
    }
    return activeSession;
}
}

Answer 2

使用它对我有用

if (fb_session != null && fb_session.isOpened()) {
  makeMeRequest(fb_session);  // if facebook session open get user information    
  Log.i("Facebook Login State == >", "Facebook Login State");     
 } else {
  if (fb_session == null) {
   fb_session = new Session(mCurrContext);            
       }
  Session.setActiveSession(fb_session);
  ConnectToFacebook(); // other wise connected to facebook
   Log.i("Facebook not Login State == >", "Facebook Not login State");
 }

} 得到例外

    01-22 04:15:34.934: E/AndroidRuntime(24283): FATAL EXCEPTION: main
01-22 04:15:34.934: E/AndroidRuntime(24283): java.lang.NullPointerException: Argument '148885915321893' cannot be null
01-22 04:15:34.934: E/AndroidRuntime(24283):    at com.facebook.internal.Validate.notNull(Validate.java:29)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at com.facebook.Session.<init>(Session.java:227)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at com.facebook.Session.<init>(Session.java:212)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at com.srikanth.ema.Transaction$HttpAsyncTask.onPostExecute(Transaction.java:182)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at com.srikanth.ema.Transaction$HttpAsyncTask.onPostExecute(Transaction.java:1)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at android.os.AsyncTask.finish(AsyncTask.java:631)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at android.os.AsyncTask.access$600(AsyncTask.java:177)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at android.os.Handler.dispatchMessage(Handler.java:99)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at android.os.Looper.loop(Looper.java:137)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at android.app.ActivityThread.main(ActivityThread.java:4960)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at java.lang.reflect.Method.invokeNative(Native Method)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at java.lang.reflect.Method.invoke(Method.java:511)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
01-22 04:15:34.934: E/AndroidRuntime(24283):    at dalvik.system.NativeStart.main(Native Method)

获取Facebook会话时出错

2 个答案: