MapKit从核心数据中添加多个注释

Question

这是我的代码。它循环查找数据库中的数字记录，但仅检索第一个记录lat和lon。

func fetch() { 
    let appDel: AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate 
    let context: NSManagedObjectContext = appDel.managedObjectContext! 
    let freq = NSFetchRequest(entityName: "Mappoints") 
    let fetchResults = try! context.executeFetchRequest(freq) as! [NSManagedObject] 
    self.mapView.delegate = self 
    myData = fetchResults 
    myData.count 
    for _ in myData { 
     let data: NSManagedObject = myData[row] 

    lat = (data.valueForKey("latitude") as? String)! 
    lon = (data.valueForKey("longitude") as? String)! 

    let latNumb = (lat as NSString).doubleValue 
    let longNumb = (lon as NSString).doubleValue 
    let signLocation = CLLocationCoordinate2DMake(latNumb, longNumb) 
    addAnnotaion(signLocation) 
    } 

} 

我确定我缺少一些简单的东西，但只是不断丢失它。

Answer 1

这做的是我结束了解决问题的代码。

func fetch() { 
    let appDel: AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate 
    let context: NSManagedObjectContext = appDel.managedObjectContext! 
    let freq = NSFetchRequest(entityName: "Mappoints") 
    let fetchResults = try! context.executeFetchRequest(freq) as! [NSManagedObject] 
    self.mapView.delegate = self 
    myData = fetchResults 
    let ct = myData.count // Add this line 
    // Then changed the for statement from for _ in myData 
    // To the line below and now all map points show up. 
    for row in 0...ct-1 { 
     let data: NSManagedObject = myData[row] 
     lat = (data.valueForKey("latitude") as? String)! 
     lon = (data.valueForKey("longitude") as? String)! 
     let latNumb = (lat as NSString).doubleValue 
     let longNumb = (lon as NSString).doubleValue 
     let signLocation = CLLocationCoordinate2DMake(latNumb, longNumb) 
     addAnnotaion(signLocation) 
    } 

Answer 2

你的循环看起来很奇怪。你说myData[row]，但你似乎没有增加行。如果该行不增加，则data变量将始终相同。

例如，您可以for data in myData { ...