Why can't I save data in plist file with Swift

Question

** the readData.plist is:**


  <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>currentChapter</key>
    <string>2</string>
    <key>currentLine</key>
    <string>2</string>
    <key>bookname</key>
    <string>ExcelBible</string>
</dict>
</plist>

** The following is code:**


        let Chapter = currentChapter
        let Line = currentLine
        let name = bookname

        let dict:NSMutableDictionary = NSMutableDictionary()



        dict.setObject("1", forKey: "currentChapter" as NSCopying)
        dict.setObject("1", forKey: "currentLine" as NSCopying)
        dict.setObject("WordBible", forKey: "bookname" as NSCopying)

        //I also use dict[0] = "1", and setValue() method both of them are not work

        let plistPath = Bundle.main.path(forResource: "readData", ofType: "plist")

        dict.write(toFile: plistPath!, atomically: true)

Blockquote I also use FileManager and several examples here to save data, some display "Successfully write", but the file does't change.

Blockquote

I am an iOS developer since Feb 12, 2020

You cannot write into the application bundle. It's read-only. And `NSCoding` is discouraged in Swift. Use `PropertyListEncoder` And never use `NSMutable...` collection types in Swift. All native types are mutable by default as `var`iable. And please conform to the naming convention and name variables and methods with starting lowercase letter. — vadian, Feb 16 '20 at 06:17
Thank your advice of PropertyListEncoder and code writing method. I changed my code, but it still does't work ``` let currentChapter = "10" let currentLine = "10" let nameOfBook = "WordBible" let readData = [currentChapter, currentLine, nameOfBook] // let dataFilePaths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0].appendingPathComponent("gameSave.plist") let data = try PropertyListEncoder().encode(readData) try? data.write(to: dataFilePaths, options: Data.WritingOptions.atomic) ``` — Dapple, Feb 17 '20 at 05:45
You have to create a struct with the 3 properties `currentChapter`, `currentLine` and `nameOfBook` and encode this to get a property list with the corresponding keys. — vadian, Feb 17 '20 at 05:51
Could you tell me why I have to use a struct? but finally, I have to execute the specific function. — Dapple, Feb 18 '20 at 18:47
Because it's more convenient, more efficient and *swiftier*. — vadian, Feb 18 '20 at 18:51
Thank you very much , I got it. because I am new, so I write code in playground, then move to project use class or struct, but now my task to solve that question. — Dapple, Feb 18 '20 at 20:10

score 0 · Answer 1 · answered Feb 16 '20 at 04:12

0

I think the file is not in a writable location, so you should create it in the documents directory. Then, it has to be read from the documents directory.

answered Feb 16 '20 at 04:12

ChickenMinh

39
1
2
11

Thank you. I tried PropertyListEncoder() method under playground and project, it doesn't work. – Dapple Feb 17 '20 at 05:48
That's not what I'm thinking about. Read [this](https://stackoverflow.com/questions/25100262/save-data-to-plist-file-in-swift) – ChickenMinh Feb 17 '20 at 05:59
it doesn't work, because I am new to develop. my friend helps me ,but he can not find the reason. – Dapple Feb 18 '20 at 18:49

score 0 · Answer 2 · answered Feb 17 '20 at 05:51

Blockquote

I used the following code, but it does't work too.

Blockquote


let currentChapter = "10"
let currentLine = "10"
let nameOfBook = "WordBible"

let readData = [currentChapter, currentLine, nameOfBook]
//

let dataFilePaths = FileManager.default.urls(for: .documentDirectory,
                                             in: .userDomainMask)[0].appendingPathComponent("gameSave.plist")

let data = try PropertyListEncoder().encode(readData)

try? data.write(to: dataFilePaths, options: Data.WritingOptions.atomic)

Why can't I save data in plist file with Swift

2 Answers2