Swift 解析 Facebook Graph API 对象时出错：EXC_BAD_INSTRUCTION(code=EXC_I386_INVOP)

Posted 2023-02-24

【中文标题】Swift 解析 Facebook Graph API 对象时出错：EXC_BAD_INSTRUCTION(code=EXC_I386_INVOP)

【英文标题】：Swift error parsing Facebook Graph API object: EXC_BAD_INSTRUCTION(code=EXC_I386_INVOP)

【发布时间】：2014-06-29 07:16:10

【问题描述】：

我试图获取 Facebook 群组信息，但遇到了一个我不知道如何解决的错误。

当我尝试访问组的 Feed 的单个项目时，我将 Feed 从 AnyObject 转换为 FBGraphObject，这就是发生错误的地方。

错误显示 “线程 1 : EXC_BAD_INSTRUCTION(code=EXC_I386_INVOP, subcode=0x0)”

我尝试进行 nil 检查，并检查对象的类型以防止错误，但并没有解决问题。

任何建议可能是什么问题？

func fetchFacebookGroup() 
    FBRequestConnection.startWithGraphpath("/\(groupId)/?fields=feed", completionHandler: (connection: FBRequestConnection!, result: AnyObject!, error: NSError!) -> Void in
        if result? 
            NSLog("error = \(error)")

            var jsonFeeds = result as FBGraphObject
            self.feeds = self.buildFeeds((jsonFeeds["feed"] as FBGraphObject)["data"] as NSMutableArray)
            self.tableView.reloadData()
        
         as FBRequestHandler)



func buildFeeds(data: NSMutableArray) -> Array<GroupFeed> 
    var result : Array<GroupFeed> = []
    for rawFeed : AnyObject in data 
        if rawFeed is FBGraphObject  // This is where error pops up.
            if let jsonFeed = rawFeed as? FBGraphObject 
                var feed = GroupFeed(id: jsonFeed["id"] as String, name: (jsonFeed["from"] as FBGraphObject)["name"] as String, message: jsonFeed["message"] as String, updatedTime: jsonFeed["updated_time"] as String)
                result.append(feed)
            
        
    

    return result

【参考方案1】：

我在解析 API 调用返回的 FBGraphObject 时更加小心，从而解决了这个问题。 事实证明，我假设此 API 返回的所有群组供稿都包含“消息”作为键是错误的。

因此，我的代码的固定版本如下：

TableViewController.swift

func fetchFacebookGroup() 
    FBRequestConnection.startWithGraphPath("\(groupId)/?fields=feed.limit=(1)", completionHandler: (connection: FBRequestConnection!, result: AnyObject!, error: NSError!) -> Void in
        if result? 
            NSLog("error = \(error)")

            var jsonFeeds = result as FBGraphObject
            self.feeds = self.buildFeeds((jsonFeeds["feed"] as FBGraphObject)["data"] as NSMutableArray)
            self.tableView.reloadData()
        
         as FBRequestHandler)



func buildFeeds(data: NSMutableArray) -> Array<GroupFeed> 
    var result : Array<GroupFeed> = []
    for rawFeed : AnyObject in data 
        if rawFeed is FBGraphObject 
            if let jsonFeed = rawFeed as? FBGraphObject 
                var feed = GroupFeed(jsonFeed: jsonFeed)
                result += feed
            
        
    
    return result

GroupFeed.swift

class GroupFeed: NSObject 
    var id : String!
    var name : String!
    var message : String?
    var updatedTime : String!

    init(jsonFeed: FBGraphObject) 
        self.id = jsonFeed["id"] as String
        self.name = (jsonFeed["from"] as FBGraphObject)["name"] as String
        if let message = jsonFeed.objectForKey("message") as? String 
            self.message = message
        
        self.updatedTime = jsonFeed["updated_time"] as String
    

所以我在这里的教训是，我不应该过分依赖 XCode 调试器准确定位错误来自何处的能力。

我不知道这是因为 XCode6 仍处于测试阶段，还是它就是这样，但在测试 IDE 之上使用全新语言时，应注意不要盲目相信该工具.