Question

当我从Firebase获取数据时，将其添加到数组中，并获取它的计数，其计数为4，但数据库中只有一个对象。

除此之外，当我尝试通过索引访问数组中的值时，即使是0，我也会得到错误＆＃34;索引超出范围＆＃34;。

class GroupsViewController: UIViewController {
var groupNames: [String?] = []

override func viewDidLoad() {
    super.viewDidLoad()
    ref.child(uid).child("Groups").observeEventType(FIRDataEventType.Value, withBlock: { (snapshot) in
                let Dict = snapshot.value as? [String : AnyObject]

                if Dict != nil {

                    for (groupIds, accesBool) in Dict! {
                        self.loadGroups(groupIds)
                    }

                }
    })
}


func loadGroups(groupID: String) {             
     ref.child("Groups").child(groupID).child("GroupName").observeSingleEventOfType(.Value, withBlock: { (snapshot) in
        let GroupName = snapshot.value as? String

        print(GroupName) --> Prints the same string 4 times 


        self.groupNames.append(GroupName)


        print(self.groupNames[0]) --> Prints ERROR Index out of range
        print(self.groupNames.count) --> Prints 4



    })


 }

Answer 1

在for循环中加载组会导致所有问题。

class GroupsViewController: UIViewController {
var groupNames: [String?] = []
var groupIdsArr: [String] = []

override func viewDidLoad() {
    super.viewDidLoad()
    ref.child(uid).child("Groups").observeEventType(FIRDataEventType.Value, withBlock: { (snapshot) in
                let Dict = snapshot.value as? [String : AnyObject]

                if Dict != nil {
                    var newIds: [String] = []
                    for (groupIds, accesBool) in Dict! {
                        newIds.append(groupIds)
                    }
                        self.groupIdsArr = newIds
                        // You can create a loop, that loads each value of the array. I inserted this into a tableview, and used indexPath.row

                        self.loadGroups(groupIdsArr[0])
                }
    })


}


func loadGroups(groupID: String) {             
  ref.child("Groups").child(groupID).child("GroupName").observeSingleEventOfType(.Value, withBlock: { (snapshot) in
        let GroupName = snapshot.value as? String

        print(GroupName) --> Prints the same string 4 times 


        self.groupNames.append(GroupName)


        print(self.groupNames[0]) --> Prints ERROR Index out of range
        print(self.groupNames.count) --> Prints 4



    })


 }

无法将Firebase结果添加到阵列

1 个答案: