为什么我不能将所有核心数据提取结果放入 UILabel 中？

Question

我有这段代码，当我使用 print 命令时，我可以获得所有的提取结果，但是如果我试图将结果放入 UILabel 中并显示它，则只会显示最后插入的值。

do {
        let result = try managedContext.fetch(fetchRequest)

        for data in result as! [NSManagedObject] {
            print(data.value(forKey: "date") as! String)
            print(data.value(forKey: "score") as! String)
            var x = data.value(forKey: "date") as! String
            var y = data.value(forKey: "score") as! String


            //allScores.text = "Session started on \(x), points earned:  \(y)"
        }
    } catch  {
         print("Failed")
    }

这样做有效，

print(data.value(forKey: "date") as! String)
            print(data.value(forKey: "score") as! String)

但这不是它只显示我的 UILabel 中最后插入的值

var x = data.value(forKey: "date") as! String
var y = data.value(forKey: "score") as! String 

allScores.text = "Session started on \(x), points earned:  \(y)"

Answer 1

像这样尝试

do {
        let result = try managedContext.fetch(fetchRequest)
        allScores.text = ""
        for data in result as! [NSManagedObject] {
            print(data.value(forKey: "date") as! String)
            print(data.value(forKey: "score") as! String)
            var x = data.value(forKey: "date") as! String
            var y = data.value(forKey: "score") as! String


            allScores.text = (allScores.text ?? "")  + "Session started on \(x), points earned:  \(y)"
        }
    } catch  {
         print("Failed")
    }

为什么我不能将所有核心数据提取结果放入 UILabel 中？

Why can't I get all my core data fetch results into a UILabel?

xcode

core-data

core

uilabel

swift