[英]How to save data from Real Time Firebase Database in Swift?
所以,在我的代碼中,你可以看到我想返回從 Firebase 檢索到的信息,但該方法總是返回一個空數組,我是 Swift 的新手,你能解釋一下為什么會發生這種情況,我該怎么做讓它起作用? 非常感謝。
var catalog:[String:NSDictionary] = [String():NSDictionary()]
func readCatalogInfo()->[String:NSDictionary]{
let ref = Database.database(url: "https://reforestar-database-default-rtdb.europe-west1.firebasedatabase.app/").reference()
_ = ref.child("trees").observe(.value, with: {snapshot in
guard let information:[String:NSDictionary] = snapshot.value as? [String:NSDictionary] else {
print("Error in getting information about the Trees")
return
}
self.catalog = information
})
return self.catalog
}
數據庫請求異步工作,您必須添加一個完成處理程序。
並且不要在 Swift 中使用NS...
集合類型
var catalog = [String:[String:Any]]()
func readCatalogInfo(completion: @escaping ([String:[String:Any]]) -> Void) {
let ref = Database.database(url: "https://reforestar-database-default-rtdb.europe-west1.firebasedatabase.app/").reference()
_ = ref.child("trees").observe(.value, with: {snapshot in
guard let information = snapshot.value as? [String:[String:Any]] else {
print("Error in getting information about the Trees")
return
}
completion(information)
})
}
並使用它
readCatalogInfo() { [weak self] result in
self?.catalog = result
}
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