将json调用语法从Objective-C转换为Swift的正确方法是什么？

Question

我正在将 ViewController 从 Objective-C 更新到 Swift，并遇到了几个错误，我的原始代码是：

/*        Line 161 read: NSString *dateString = [NSString stringWithFormat:@"%i-%i", start.month, start.day];
*/       This is from Objective-c file to call Holiday.json file 


NSString *dateString = [NSString, stringWithFormat;@"%li-%li", (long)start.month, (long)start.day];

NSString *filePath = [[NSBundle mainBundle] pathForResource:@"Holidays" ofType:@"json"];

NSString *holidayJSON = [[NSString alloc] initWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:NULL];

if (holidayJSON) {

    NSData *jsonData = [holidayJSON dataUsingEncoding:NSUTF8StringEncoding];



    NSDictionary *results = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:nil];

    NSDictionary *holiday = [results objectForKey:dateString];

    NSDictionary *titleDescription = [holiday objectForKey:@"holidays"];

    NSLog(@"holiday %@", titleDescription);



    NSString *title = [[titleDescription valueForKey:@"title"]objectAtIndex:0];

    NSString *description = [[titleDescription valueForKey:@"description"]objectAtIndex:0];



    NSLog(@"title: %@, description: %@", title, description);

    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:title message:description delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil];

    [alertView show];

}



NSLog( @"Selected %ld/%ld - %ld/%ld", (long)range.startDay.day, (long)range.startDay.month, (long)range.endDay.day, (long)range.endDay.month);

}

else {

    NSLog( @"No selection" );

  }

}

在尝试将其更改为 Swift 时，我遇到了几个错误：

// have calendar present a holiday from the JSON file for each day


let filePath: String = NSBundle.mainBundle().pathForResource("Holiday", ofType: "json") as String!
let jsonData = NSData(contentsOfFile:filePath) as NSData!
let dateString = ["%li-%li",DayView.monthstart.day] as NSString!
var holidayJSON: String = NSString(contentsOfFile: filePath, encoding: NSUTF8StringEncoding, error: nil)
if holidayJSON {
    var jsonData: NSData = holidayJSON.dataUsingEncoding(NSUTF8StringEncoding)
    var results: [NSObject : AnyObject] = NSJSONSerialization.JSONObjectWithData(jsonData, options: 0, error: nil)
    var holiday: [NSObject : AnyObject] = results[dateString]
    var titleDescription: [NSObject : AnyObject] = holiday["holidays"]
    NSLog("holiday %@", titleDescription)
    var title: String = titleDescription.valueForKey("title").objectAtIndex(0)
    var description: String = titleDescription.valueForKey("description").objectAtIndex(0)
    NSLog("title: %@, description: %@", title, description)
    var alertView: UIAlertView = UIAlertView(title: title, message: description, delegate: nil, cancelButtonTitle: "Ok", otherButtonTitles: nilnil)
    alertView.show()
}
NSLog("Selected %ld/%ld - %ld/%ld", range.startDay.day, range.startDay.month, range.endDay.day, range.endDay.month)

Answer 1

我对coding/stackoverflow/etc..etc还是很陌生...所以当我提出这个问题时，我正在寻找关于如何解决问题的其他想法，我遇到了一个视频说我可以使用桥接在 swift 项目中使用 Objective-c 的头文件。这是我当时没有想到的一种解决方案。但我能够从更有经验的人那里获得一些帮助，这是一个不会出现错误的 swift 版本：

`//        Line 161 read: NSString *dateString = [NSString                           stringWithFormat:@"%i-%i", start.month, start.day];
//        This is from Objective-c file to call Holiday.json file

func holidayForDate(date:CVDate) {
//let cal = NSCalendar.currentCalendar()
// let components = cal.components([.Month, .Day], fromDate: date)
let dateString = "\(date.month)-\(date.day)"

guard let path : String = NSBundle.mainBundle().pathForResource("Holiday", ofType: "json") else {
    // TODO error handling?
    return
}
guard let jsonData = NSData(contentsOfFile: path) else {
    // TODO error handling?
    return
}
do {
    guard let dict:[String:AnyObject] = try NSJSONSerialization.JSONObjectWithData(jsonData, options: []) as? [String : AnyObject] else {
        // TODO error handling
        return
    }
    let holidays:[[String:String]] = dict[dateString] as! [[String:String]]
    if let holiday = holidays.first {
        let title = holiday["title"]
        let description = holiday["description"]
        UIAlertView(title: title, message: description, delegate: nil, cancelButtonTitle: "OK").show()
    }
}
catch {
    NSLog("\(error)")
}

}

} `