在swift 2.0中将NSArray投射到NSMutable Array

问题描述：

当我尝试将nsarray对象插入到可变的swift数组时，我得到了此控制台输出。代码工作正常，但最后，它是抛出一个错误。请帮我解决这个错误。在swift 2.0中将NSArray投射到NSMutable Array

Successfully retrieved 3 scores. 
 
Optional("HmEbbowtxW") 
 
<Events: 0x7b08bdf0, objectId: HmEbbowtxW, localId: (null)> { 
 
    CreatedBy = "<PFUser: 0x7b02ed10, objectId: 04jp1ZeBn6>"; 
 
    EventDescription = test; 
 
    EventName = test; 
 
} 
 
Optional("97BzKUxFdE") 
 
<Events: 0x7b08cae0, objectId: 97BzKUxFdE, localId: (null)> { 
 
    CreatedBy = "<PFUser: 0x7b02ed10, objectId: 04jp1ZeBn6>"; 
 
    EventDescription = fg; 
 
    EventName = gfg; 
 
} 
 
Optional("QDHkg5tiUw") 
 
<Events: 0x7b08cf80, objectId: QDHkg5tiUw, localId: (null)> { 
 
    CreatedBy = "<PFUser: 0x7b02ed10, objectId: 04jp1ZeBn6>"; 
 
    EventDescription = asdasdasd; 
 
    EventName = sdsd; 
 
} 
 
Could not cast value of type '__NSArrayI' (0x228e164) to 'NSMutableArray' (0x228e1c8).

这是我的代码

let query = PFQuery(className:"Events") 
 
     query.whereKey("CreatedBy", equalTo:PFUser.currentUser()!) 
 
     
 
     query.findObjectsInBackgroundWithBlock { 
 
      (objects, error) -> Void in 
 
      
 
      if error == nil { 
 
       // The find succeeded. 
 
       print("Successfully retrieved \(objects!.count) scores.") 
 
       // Do something with the found objects 
 
       if let objects = objects as? [PFObject] { 
 
        for object in objects { 
 
         
 
         self.eventtimelineData.addObject(object) 
 
         print(object.objectId) 
 
         print(object.description) 
 
        } 
 
        
 
        let array:NSArray = self.eventtimelineData.reverseObjectEnumerator().allObjects 
 
        self.eventtimelineData = array as! NSMutableArray 
 
        self.tableView.reloadData() 
 
        
 
       } 
 
       
 
       
 
      } else { 
 
       // Log details of the failure 
 
       print("Error: \(error!) \(error!.userInfo)") 
 
      } 
 
     }

答

要将NSArray转换为NSMutableArray，叫mutableCopy()和转换为NSMutableArray：

let a: NSArray = [1, 2.5, "hello"] 

let b = a.mutableCopy() as! NSMutableArray 

b.addObject(17) // b is [1, 2.5, "hello", 17]

工作。谢谢！ –

答

您不能从NSArray转换为NSMutableArray。您需要创建一个新的可变阵列：

self.eventtimelineData = array.mutableCopy() as! NSMutableArray

工作。谢谢！ –

在swift 2.0中将NSArray投射到NSMutable Array

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