我希望切换键盘时视图向上移动。它适用于我所有的其他观点，但在这一点中它不起作用。它说"unexpectedly found nil while unwrapping an Optional value"
这是我的代码：
class SecondViewController: UIViewController , UIPickerViewDelegate, UIPickerViewDataSource{
@IBOutlet var ScrollView: UIScrollView!
@IBOutlet weak var codeaffiche: UILabel!
@IBOutlet var Prix: UITextField!
@IBOutlet var NomProduit: UITextField!
@IBOutlet var picker1: UIPickerView!
@IBOutlet var NomMAG: UITextField!
var nom_magasin :String!
var pickerData = [String]()
var pickerDataRow = [String]()
override func viewDidLoad() {
super.viewDidLoad()
codeaffiche.text = detectionString
NomMAG.alpha = 0
let str = "http://vps43623.ovh.net/yamoinscher/api/getAllMag"
let url = NSURL(string: str)!
let task = NSURLSession.sharedSession().dataTaskWithURL(url) { (data, response, error) -> Void in
if let urlContent = data {
do {
let jsonObject = try NSJSONSerialization.JSONObjectWithData(urlContent, options: [])
if let jsonResult = jsonObject as? [String:AnyObject],
magasin = jsonResult["magasin"] as? [[String:String]] {
// filter valid items, map them to an array and filter empty strings
self.pickerData = magasin.filter { $0["libelle"] != nil }.map { $0["libelle"]! }.filter { !$0.isEmpty}
self.pickerDataRow = magasin.filter { $0["id"] != nil }.map { $0["id"]! }.filter { !$0.isEmpty}
self.pickerData.append("choisir magasin")
}
dispatch_async(dispatch_get_main_queue()) {
self.picker1.reloadAllComponents()
}
} catch {
print("JSON serialization failed", error)
}
} else if let connectionError = error {
print("connection error", connectionError)
}
}
task.resume()
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
ScrollView.keyboardDismissMode = .OnDrag
}
func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
func textFieldDidBeginEditing(textField: UITextField) {
if textField == NomMAG {
ScrollView.setContentOffset(CGPointMake(0, 250), animated: true)
}
}
func textFieldDidEndEditing(textField: UITextField) {
if textField == NomMAG {
ScrollView.setContentOffset(CGPointMake(0,0), animated: true)
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// The number of columns of data
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
return 1
}
// The number of rows of data
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return self.pickerData.count
}
// The data to return for the row and component (column) that's being passed in
func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return self.pickerData[row]
}
func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
if pickerData[row] == "choisir magasin"
{
//print(row)
NomMAG.alpha = 1
nom_magasin = NomMAG.text
}
else
{
//print(row.description)
NomMAG.alpha = 0
nom_magasin = pickerData[row]
}
}
@IBAction func AddProduct(sender: AnyObject) {
let myUrl = NSURL(string: "http://vps43623.ovh.net/yamoinscher/ios/products/addIos");let request = NSMutableURLRequest(URL:myUrl!);
request.HTTPMethod = "POST";
// Compose a query string
let postString = "code_barre=\(detectionString!)&&libelle=\(NomProduit.text!)&nom_magasin=\(nom_magasin!)&prix=\(Prix.text!)"
let postLength = String(postString.characters.count)
request.HTTPBody = postString.dataUsingEncoding(NSUTF8StringEncoding)
request.setValue(postLength, forHTTPHeaderField: "Content-Length")
request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
request.setValue("application/json", forHTTPHeaderField: "Accept")
let task = NSURLSession.sharedSession().dataTaskWithRequest(request) {
data, response, error in
if error != nil
{
print("error=\(error)")
return
}
// print out response object
print("response = \(response)")
// Print out response body
let responseString = NSString(data: data!, encoding: NSUTF8StringEncoding)
print("responseString = \(responseString)")
}
task.resume()
}
}