Facebook SDK Swift-使用未声明的标识符

我正在获得Use of undeclared identifier使用的每个Facebook对象

遵循本教程：教程：如何在SWIFT中共享FACEBOOK SDK 4.1.X

但是我遇到了以下错误：

我通过cocoapods添加了Facebook框架：

pod 'FBSDKCoreKit'
pod 'FBSDKShareKit'

并成功安装

我添加了桥接头

#ifndef Bridging_Header_h
#define Bridging_Header_h

#import <FBSDKCoreKit/FBSDKCoreKit.h>
#import <FBSDKShareKit/FBSDKShareKit.h>

#endif /* Bridging_Header_h */

桥接头已连接：

我已经配置了.plist

<key>CFBundleURLTypes</key>
    <array>
        <dict>
            <key>CFBundleURLSchemes</key>
            <array>
                <string>fb*****</string>
            </array>
        </dict>
    </array>
    <key>FacebookAppID</key>
    <string>*****</string>
    <key>FacebookDisplayName</key>
    <string>*****</string>
    <key>NSAppTransportSecurity</key>
    <dict>
        <key>NSExceptionDomains</key>
        <dict>
            <key>facebook.com</key>
            <dict>
                <key>NSIncludesSubdomains</key> <true/>
                <key>NSThirdPartyExceptionRequiresForwardSecrecy</key> <false/>
            </dict>
            <key>fbcdn.net</key>
            <dict>
                <key>NSIncludesSubdomains</key> <true/>
                <key>NSThirdPartyExceptionRequiresForwardSecrecy</key>  <false/>
            </dict>
            <key>akamaihd.net</key>
            <dict>
                <key>NSIncludesSubdomains</key> <true/>
                <key>NSThirdPartyExceptionRequiresForwardSecrecy</key> <false/>
            </dict>
        </dict>
    </dict>

这是代码：

let content : FBSDKShareLinkContent = FBSDKShareLinkContent()
        content.contentURL = NSURL(string: "<INSERT STRING HERE>")
        content.contentTitle = "<INSERT STRING HERE>"
        content.contentDescription = "<INSERT STRING HERE>"
        content.imageURL = NSURL(string: "<INSERT STRING HERE>")

        let button : FBSDKShareButton = FBSDKShareButton()
        button.shareContent = content
        button.frame = CGRectMake((UIScreen.mainScreen().bounds.width - 100) * 0.5, 50, 100, 25)
        self.view.addSubview(button)