Swift 2数据库路径问题

Question

我正在学习在iOS应用程序开发过程中使用数据库的文本教程(http://www.techotopia.com/index.php/An_Example_SQLite_based_iOS_8_Application_using_Swift_and_FMDB)

在以下代码中：

     databasePath = docsDir.stringByAppendingPathComponent("contacts.db")

出现错误：

"stringByAppendingPathComponent"不可用：请改为在NSURL上使用URLByAppending PathComponent。

当我尝试这个建议时：

databasePath = NSURL(fileURLWithPath:NSTemporaryDirectory()).URLByAppendingPathComponent("contacts.db")

我意识到，通过修改，我们现在使用的是URL，而不是字符串，但我不知道对代码还有什么其他更改

完整代码：

import UIKit

类ViewController:UIViewController｛

@IBOutlet weak var name: UITextField!
@IBOutlet weak var address: UITextField!
@IBOutlet weak var phone: UITextField!
@IBOutlet weak var status: UILabel!
var databasePath = NSString()
override func viewDidLoad() {
    super.viewDidLoad()
    let filemgr = NSFileManager.defaultManager()
    let dirPaths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory,.UserDomainMask, true)
    let docsDir = dirPaths[0] as! String
    databasePath = docsDir.stringByAppendingPathComponent(
    "contacts.db")
    if !filemgr.fileExistsAtPath(databasePath as String) {
        let contactDB = FMDatabase(path: databasePath as String)
        if contactDB == nil {
            print("Error: (contactDB.lastErrorMessage())")
        }
        if contactDB.open() {
            let sql_stmt = "CREATE TABLE IF NOT EXISTS CONTACTS (ID INTEGER PRIMARY KEY AUTOINCREMENT, NAME TEXT, ADDRESS TEXT, PHONE TEXT)"
            if !contactDB.executeStatements(sql_stmt) {
                print("Error: (contactDB.lastErrorMessage())")
            }
            contactDB.close()
        } else {
            print("Error: (contactDB.lastErrorMessage())")
        }
    }
}
override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
@IBAction func saveData(sender: AnyObject) {
    let contactDB = FMDatabase(path: databasePath as String)
    if contactDB.open() {
        let insertSQL = "INSERT INTO CONTACTS (name, address, phone) VALUES ('(name.text)', '(address.text)', '(phone.text)')"
        let result = contactDB.executeUpdate(insertSQL,
            withArgumentsInArray: nil)
        if !result {
            status.text = "Failed to add contact"
            print("Error: (contactDB.lastErrorMessage())")
        } else {
            status.text = "Contact Added"
            name.text = ""
            address.text = ""
            phone.text = ""
        }
    } else {
        print("Error: (contactDB.lastErrorMessage())")
    }
}
@IBAction func findContact(sender: AnyObject) {
    let contactDB = FMDatabase(path: databasePath as String)
    if contactDB.open() {
        let querySQL = "SELECT address, phone FROM CONTACTS WHERE name = '(name.text)'"
        let results:FMResultSet? = contactDB.executeQuery(querySQL,
            withArgumentsInArray: nil)
        if results?.next() == true {
            address.text = results?.stringForColumn("address")
            phone.text = results?.stringForColumn("phone")
            status.text = "Record Found"
        } else {
            status.text = "Record not found"
            address.text = ""
            phone.text = ""
        }
        contactDB.close()
    } else {
        print("Error: (contactDB.lastErrorMessage())")
    }
}

}

Answer 1

URLByAppendingPathComponent返回NSURL是正确的，但您可以始终使用absoluteString将路径作为String，并继续使用该字符串，就像您已经做过的那样：

let databaseURL = NSURL(fileURLWithPath:NSTemporaryDirectory()).URLByAppendingPathComponent("contacts.db")
let databasePath = databaseURL.absoluteString

或者你可以走捷径，直接建立数据库路径，而不使用NSURL：

let databasePath = NSTemporaryDirectory() + "database.db"