FacebookFragment.java 文件源码

/**
 * Gets the date at which the current session will expire or null if no session 
 * has been created.
 * 
 * @return the date at which the current session will expire
 */
protected final Date getExpirationDate() {
    if (sessionTracker != null) {
        Session currentSession = sessionTracker.getOpenSession();
        return (currentSession != null) ? currentSession.getExpirationDate() : null;
    }
    return null;
}