问题
I have never worked with a picker view before. I assume it would be similar to the func tableView(tableView: UITableView, didDeselectRowAtIndexPath indexPath: NSIndexPath) method of the table view class. However I can not figure out how I will get the text from the picker value and display that in a label. I would like this to be done inside the postListing method.Can someone help me out with this please? Thanks.
import UIKit
class BooksViewController: UIViewController , UIPickerViewDelegate, UIPickerViewDataSource, UIImagePickerControllerDelegate , UINavigationControllerDelegate {
@IBOutlet var bookImage: UIImageView!
@IBOutlet var coursePicker: UIPickerView!
@IBOutlet var bookDescription: UITextField!
@IBOutlet var pickerSelectionLabel: UILabel!
var photoSelected = false
var activityIndicator:UIActivityIndicatorView = UIActivityIndicatorView()
@IBAction func pickImage(sender: AnyObject) {
println("pick image pressed")
var image = UIImagePickerController()
image.delegate = self
image.sourceType = UIImagePickerControllerSourceType.PhotoLibrary
image.allowsEditing = false
self.presentViewController(image, animated: true, completion: nil)
}
@IBAction func postListing(sender: AnyObject) {
var error = ""
if (photoSelected == false) {
error = "Please select an image."
} else if (bookDescription.text == "") {
error = "Please enter a description"
}
if (error != "") {
displayAlert("Can't Post Image", error: error)
} else {
let actIndPoint = CGPointMake(self.view.center.x, self.view.center.y)
activityIndicator = UIActivityIndicatorView(frame: CGRectMake(0, 0, 50, 50))
activityIndicator.center = actIndPoint
activityIndicator.hidesWhenStopped = true
activityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.Gray
view.addSubview(self.activityIndicator)
activityIndicator.startAnimating()
UIApplication.sharedApplication().beginIgnoringInteractionEvents()
var bookPosting = PFObject(className: "BookPosting")
bookPosting["Description"] = bookDescription.text
bookPosting["username"] = PFUser.currentUser().username
//bookPosting["subject"] = coursePicker
bookPosting.saveInBackgroundWithBlock({ (success: Bool!, error: NSError!) -> Void in
self.activityIndicator.stopAnimating()
UIApplication.sharedApplication().endIgnoringInteractionEvents()
if (success == false) {
self.displayAlert("Can't Post Image", error: "Please try again")
} else {
let imageData = UIImagePNGRepresentation(self.bookImage.image)
let imageFile = PFFile(name: "image.png", data: imageData)
bookPosting["imageFile"] = imageFile
bookPosting.saveInBackgroundWithBlock({ (success: Bool!, error: NSError!) -> Void in
if (success == false) {
self.displayAlert("Can't Post Image", error: "Please try again")
} else {
println("Successful post!")
self.displayAlert("Your image has been posted", error: "Posted Successfully")
self.photoSelected = false
self.bookImage.image = UIImage(named: "book1.png")
self.bookDescription.text = ""
}
})
}
})
}
println("post listing pressed")
}
func displayAlert(title: String, error: String) {
var alert = UIAlertController(title: title, message: error, preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "OK", style: .Default, handler: { action in
self.dismissViewControllerAnimated(true, completion: nil)
}))
self.presentViewController(alert, animated: true, completion: nil)
}
func imagePickerController(picker: UIImagePickerController!, didFinishPickingImage image: UIImage!, editingInfo: [NSObject : AnyObject]!) {
self.dismissViewControllerAnimated(true, completion: nil)
bookImage.image = image
photoSelected = true
}
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return courseCatalog.count
}
func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
return courseCatalog[row]
}
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
self.view.endEditing(true)
}
override func viewDidLoad() {
println("Books view controller")
super.viewDidLoad()
photoSelected = false
bookImage.image = UIImage(named: "book1.png")
bookDescription.text = ""
}
}
回答1:
this is the Delegate method of select the components from Picker
func pickerView(pickerView: UIPickerView!, didSelectRow row: Int, inComponent component: Int)
{
println("\(courseCatalog[row])")
yourlabelname.text=courseCatalog[row]
}
来源：https://stackoverflow.com/questions/29191162/how-to-implement-the-didselectrow-method-of-the-pickerview-class