Question

我是swift的新手，我在PlacesTableViewController类中声明初始化程序时遇到问题。它提示我“在从初始化程序返回之前没有调用Super.init”，当我添加Super.init时，它会提示我：

“必须调用超类的指定初始值设定项 '的UITableViewController'“

这是我的PlacesTableViewController.swift文件：

class PlacesTableViewController: UITableViewController { 

    var pa55DB : COpaquePointer = nil
    var selectStatement : COpaquePointer = nil;

    var chapterdata : Array<Entry> = []
    var ety : Entry
    var sqlString : String = "";

    var chpData : ChapterData

    init(pa55DB : COpaquePointer,selectStatement : COpaquePointer, chapterdata : Array<Entry>, ety : Entry, sqlString : String) {
        super.init()
        self.pa55DB = pa55DB
        self.selectStatement = selectStatement
        self.chapterdata = chapterdata
        self.ety = ety
        self.sqlString = sqlString

    }

    required init!(coder aDecoder: NSCoder!) {
        fatalError("init(coder:) has not been implemented")
    }


    override func viewDidLoad() {
        super.viewDidLoad()

        chpData = ChapterData(newEntryArray : chapterdata, entryV : ety, paDB55 : pa55DB, selectStatement : selectStatement, sqlString : sqlString)
        chpData.openDB()
        chapterdata = chpData.prepareStartment()

        println("Testing...")
    }
...
}

这是我的另一个名为ChapterData.swift的类文件，用于打开数据库和检索数据

class Entry {

    let image : String!
    let heading : String!
    let title : String!
    let description : String!
    public init(image : String, heading : String, title : String, desc : String) {
        self.heading = heading
        self.image = image
        self.title = title
        self.description = desc
    }
}


class ChapterData {

    var paDB : COpaquePointer = nil;
    var selectStatement : COpaquePointer = nil;
    var sqlString : String = "";

    var newEntryArray : Array<Entry> = [];
    var entryV : Entry;

    init(newEntryArray : Array<Entry>, entryV : Entry, paDB55 : COpaquePointer, selectStatement : COpaquePointer, sqlString : String){
        self.newEntryArray = newEntryArray
        self.entryV = entryV
        self.paDB = paDB55
        self.selectStatement = selectStatement
        self.sqlString = sqlString
    }

    func openDB() {
        var paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as! String
        var docsDir = paths.stringByAppendingPathComponent("pa55.sqlite")


        if (sqlite3_open(docsDir, &paDB) == SQLITE_OK) {
            println("success open database")
        }
        else {
            println("failed to open database")
        }
    }

    func prepareStartment() -> Array<Entry>   {
        sqlString = "SELECT * FROM Chapter ORDER BY CID ASC"
        var cSql = sqlString.cStringUsingEncoding(NSUTF8StringEncoding)
        sqlite3_prepare_v2(paDB, cSql!, -1, &selectStatement, nil)

        println("startment start")

        while (sqlite3_step(selectStatement) == SQLITE_ROW) {

            let image_buf = sqlite3_column_text(selectStatement, 3)
            var image = String.fromCString(UnsafePointer<CChar>(image_buf))

            let heading_buf = sqlite3_column_text(selectStatement, 1)
            var heading = String.fromCString(UnsafePointer<CChar>(heading_buf))

            let title_buf = sqlite3_column_text(selectStatement, 2)
            var title = String.fromCString(UnsafePointer<CChar>(title_buf))

            let desc_buf = sqlite3_column_text(selectStatement, 4)
            var description = String.fromCString(UnsafePointer<CChar>(desc_buf))

            entryV = Entry(image: image!, heading: heading!, title: title!, desc: description!)
            newEntryArray.append(entryV)
        }
        println("select statement successful executed")
        return newEntryArray
    }

}

Answer 1

init混乱是ObjC＆lt; - ＆gt;的已知限制。快速过渡。

解决此问题的一种方法是委托super init(nibName:bundle:)初始化程序。

class PlacesTableViewController: UITableViewController { 

    var chapterdata: [Entry]
    var chpData: ChapterData?
    var ety: Entry
    var pa55DB: COpaquePointer
    var selectStatement: COpaquePointer
    var sqlString: String


    init(pa55DB: COpaquePointer, selectStatement: COpaquePointer, chapterdata: [Entry], ety: Entry, sqlString: String) {
        self.pa55DB = pa55DB
        self.selectStatement = selectStatement
        self.chapterdata = chapterdata
        self.ety = ety
        self.sqlString = sqlString

        super.init(nibName: nil, bundle: nil)
    }


    required init(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    // …
}

Answer 2

看看这是否可以解决您的问题：

override init(style: UITableViewStyle) {
    super.init(style: style)
}

init(pa55DB : COpaquePointer,selectStatement : COpaquePointer, chapterdata : Array<Entry>, ety : Entry, sqlString : String) {
    super.init(style: UITableView.Style.plain)
    self.pa55DB = pa55DB
    self.selectStatement = selectStatement
    self.chapterdata = chapterdata
    self.ety = ety
    self.sqlString = sqlString

}

UITableView Class Reference

来自Swift编程语言指南：

指定的初始值设定项是类的主要初始值设定项。一个指定的初始化程序完全初始化所引入的所有属性该类并调用适当的超类初始化程序继续初始化过程超级链。

[read more]

<强>更新

上述代码实际上解决了您指定的初始化程序的问题。您现在需要正确初始化您的self.ety属性。

Answer 3

也许尝试这样的事情：

class PlacesTableViewController: UITableViewController { 

   var chapterdata: [Entry]
   var chpData: ChapterData?
   var ety: Entry
   var pa55DB: COpaquePointer
   var selectStatement: COpaquePointer
   var sqlString: String


   convenience init(pa55DB: COpaquePointer, selectStatement: COpaquePointer, chapterdata: [Entry], ety: Entry, sqlString: String) {
       self.init()

       self.pa55DB = pa55DB
       self.selectStatement = selectStatement
       self.chapterdata = chapterdata
       self.ety = ety
       self.sqlString = sqlString

   }

   required init(coder aDecoder: NSCoder) {
       super.init(coder: aDecoder)
   }

   // …
}

Answer 4

UITableViewController对高级用例没有任何好处。您可以始终将UIViewController子类化并在其中添加UITableView属性，如下所示：

class PlacesTableViewController: UIViewController {

    let tableView = UITableView(frame: CGRectZero, style: .Plain)

    override func loadView() {
        view = tableView
    }

    // Custom designated initializer
    init(pa55DB : COpaquePointer,selectStatement : COpaquePointer, chapterdata : Array<Entry>, ety : Entry, sqlString : String) {
        // setting up these properties
        super.init(nibName: nil, bundle: nil)  // designated initializer of the superclass 'UIViewController'"
    }
}

它的作用类似于UITableViewController。

其他实用程序UITableViewController提供了refreshControl，您也可以为自己设置一个，clearsSelectionOnViewWillAppear机制也可以viewWillAppear()或didSelectRowAtIndexPath实施根据你的需要。

如何解决UITableViewController的指定初始化错误？

4 个答案: