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我正嘗試使用JSON庫保存數據本地化。這是我目前的代碼:如何使用SwiftyJSON保存JSON數據
var jsonFile = "json.json"
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let jsonFile = "file.json"
let jsonArray:JSON = [
"array": [12.34, 56.78],
"users": [
[
"id": 987654,
"info": [
"name": "jack",
"email": "[email protected]"
],
"feeds": [98833, 23443, 213239, 23232]
],
[
"id": 654321,
"info": [
"name": "jeffgukang",
"email": "[email protected]"
],
"feeds": [12345, 56789, 12423, 12412]
]
]
]
if let dir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
{
let path = dir.appendingPathComponent(jsonFile)
if(!FileManager.default.fileExists(atPath: path.path))
{
FileManager.default.createFile(atPath: path.path, contents: Data(), attributes: nil)
print("Created file")
do {
try write(json: jsonArray, to: path)
} catch let error{
print("Error: \(error.localizedDescription)")
}
try! write(json: jsonArray, to: path)
} else {
print("File existed")
do {
let myJSON = try readJSON(myURL: path)
if let _ = myJSON
{
print("Got data")
} else {
print("No Data")
}
} catch let errorOne {
print("Error2: \(errorOne.localizedDescription)")
}
}
}
}
}
let url = Bundle.main.url(forResource: "json", withExtension: "json")
func readJSON(myURL:URL) throws -> JSON? {
if let dir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
{
let path = dir.appendingPathComponent(jsonFile)
if(!FileManager.default.fileExists(atPath: path.path))
{
let data = try Data(contentsOf: path, options: .alwaysMapped)
return JSON(data: data)
}
}
return nil
}
func write(json: JSON, to url: URL) throws {
let data = try json.rawData()
if let dir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
{
let path = dir.appendingPathComponent(jsonFile)
if(!FileManager.default.fileExists(atPath: path.path))
{
try data.write(to: path)
}
}
}
當您第一次運行該程序時,它會創建該文件並'寫入jsonArray'。當你再次運行它時,它會'加載'JSON數據。
問題是,readJSON(myURL: path)
返回的值等於nil
。
如何在ios 10.2上使用SwiftyJSON讀取和寫入JSON數據?
更新
我已執行我在iPhone 6s
模擬器應用程序,並檢查保存的文件json.json
。這裏是保存的文件:
{"array":[12.34,56.78],"users":[{"id":987654,"info":{"name":"jack","email":"[email protected]"},"feeds":[98833,23443,213239,23232]},{"id":654321,"info":{"name":"jeffgukang","email":"[email protected]"},"feeds":[12345,56789,12423,12412]}]}
爲什麼不使用'try-catch'來處理錯誤?除此之外,即使文檔目錄中的文件存在,也始終無法創建JSON。 – vadian
@vadian這只是玩圖書館的代碼。此代碼不會用於項目中。我只想知道如何保存和加載JSON數據。另外,我的程序不會崩潰。它只是返回零。 – iProgram
'try-catch'不會**捕獲異常/崩潰。它報告錯誤。強烈建議在所有情況下使用它都可能會發生錯誤。調試你的代碼。設置斷點。使用調試器。 – vadian