问题
I am slowly working my way through Apple's learn developing for Swift and I keep running into an issue with my tap gesture. I have re-created the project numbers times all with the same outcome.
I add a tap gesture to an image view and this should open the photo library from my computer. Nothing happens.
When I download and run the sample file from Apple everything works. When I copy and paste the code from Apple's to mine, again, nothing happens. I have gone through everything that I can but feel that I am missing something.
Here is my code. Apple's code is below:
import UIKit
class ViewController: UIViewController, UITextFieldDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
// MARK: Properties
@IBOutlet weak var nameTextField: UITextField!
@IBOutlet weak var mealNameLabel: UILabel!
@IBOutlet weak var photoImageView: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
// handle the text fields user input through delegate callbacks
nameTextField.delegate = self
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: UITextFieldDelegate
func textFieldShouldReturn(textField: UITextField) -> Bool {
// Hide the Keyboard
textField.resignFirstResponder()
return true
}
func textFieldDidEndEditing(textField: UITextField) {
mealNameLabel.text = textField.text
}
// MARK: UIImagePickerControllerDelegate
func imagePickerControllerDidCancel(picker: UIImagePickerController) {
// dismiss the picker if user cancels
dismissViewControllerAnimated(true, completion: nil)
}
func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
// The info dictionary contains multiple representations of the image, and this uses the original.
let selectedImage = info[UIImagePickerControllerOriginalImage] as! UIImage
// Set the photoviewimage to be the selected image
photoImageView.image = selectedImage
// Dismiss the picker
dismissViewControllerAnimated(true, completion: nil)
}
// MARK: Actions
@IBAction func selectImageFromPhotoLibrary(sender: UITapGestureRecognizer) {
// Hide the Keyboard
nameTextField.resignFirstResponder()
// UIImagePickerController is a view controller that lets a user pick media from their photo library.
let imagePickerController = UIImagePickerController()
// Only Allow pictures to be selected and not taken
imagePickerController.sourceType = .PhotoLibrary
// make sure the viewcontroller is notified when the user selects an image
imagePickerController.delegate = self
presentViewController(imagePickerController, animated: true, completion: nil)
}
@IBAction func setDefaultLabelText(sender: UIButton) {
mealNameLabel.text = "Default Text"
}
}
Here is Apple's code:
import UIKit
class ViewController: UIViewController, UITextFieldDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
// MARK: Properties
@IBOutlet weak var nameTextField: UITextField!
@IBOutlet weak var mealNameLabel: UILabel!
@IBOutlet weak var photoImageView: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
// Handle the text field’s user input through delegate callbacks.
nameTextField.delegate = self
}
// MARK: UITextFieldDelegate
func textFieldShouldReturn(textField: UITextField) -> Bool {
// Hide the keyboard.
textField.resignFirstResponder()
return true
}
func textFieldDidEndEditing(textField: UITextField) {
mealNameLabel.text = textField.text
}
// MARK: UIImagePickerControllerDelegate
func imagePickerControllerDidCancel(picker: UIImagePickerController) {
// Dismiss the picker if the user canceled.
dismissViewControllerAnimated(true, completion: nil)
}
func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
// The info dictionary contains multiple representations of the image, and this uses the original.
let selectedImage = info[UIImagePickerControllerOriginalImage] as! UIImage
// Set photoImageView to display the selected image.
photoImageView.image = selectedImage
// Dismiss the picker.
dismissViewControllerAnimated(true, completion: nil)
}
// MARK: Actions
@IBAction func selectImageFromPhotoLibrary(sender: UITapGestureRecognizer) {
// Hide the keyboard.
nameTextField.resignFirstResponder()
// UIImagePickerController is a view controller that lets a user pick media from their photo library.
let imagePickerController = UIImagePickerController()
// Only allow photos to be picked, not taken.
imagePickerController.sourceType = .PhotoLibrary
// Make sure ViewController is notified when the user picks an image.
imagePickerController.delegate = self
presentViewController(imagePickerController, animated: true, completion: nil)
}
@IBAction func setDefaultLabelText(sender: UIButton) {
mealNameLabel.text = "Default Text"
}
}
Working Code from Anbu
import UIKit
class ViewController: UIViewController, UITextFieldDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
// MARK: Properties
@IBOutlet weak var nameTextField: UITextField!
@IBOutlet weak var mealNameLabel: UILabel!
@IBOutlet weak var photoImageView: UIImageView!
override func viewDidLoad() {
let tapgesture = UITapGestureRecognizer(target: self, action: Selector("imagepressed"))
photoImageView.userInteractionEnabled = true
photoImageView.addGestureRecognizer(tapgesture)
super.viewDidLoad()
// handle the text fields user input through delegate callbacks
nameTextField.delegate = self
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: UITextFieldDelegate
func textFieldShouldReturn(textField: UITextField) -> Bool {
// Hide the Keyboard
textField.resignFirstResponder()
return true
}
func textFieldDidEndEditing(textField: UITextField) {
mealNameLabel.text = textField.text
}
// MARK: UIImagePickerControllerDelegate
func imagePickerControllerDidCancel(picker: UIImagePickerController) {
// dismiss the picker if user cancels
dismissViewControllerAnimated(true, completion: nil)
}
func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
// The info dictionary contains multiple representations of the image, and this uses the original.
let selectedImage = info[UIImagePickerControllerOriginalImage] as! UIImage
// Set the photoviewimage to be the selected image
photoImageView.image = selectedImage
// Dismiss the picker
dismissViewControllerAnimated(true, completion: nil)
}
// MARK: Actions
func imagepressed () {
nameTextField.resignFirstResponder()
// UIImagePickerController is a view controller that lets a user pick media from their photo library.
let imagePickerController = UIImagePickerController()
// Only Allow pictures to be selected and not taken
imagePickerController.sourceType = .PhotoLibrary
// make sure the viewcontroller is notified when the user selects an image
imagePickerController.delegate = self
presentViewController(imagePickerController, animated: true, completion: nil)
}
/* @IBAction func selectImageFromPhotoLibrary(sender: UITapGestureRecognizer) {
let tapgesture = UITapGestureRecognizer(target: self, action: Selector("imagepressed"))
photoImageView.userInteractionEnabled = true
photoImageView.addGestureRecognizer(tapgesture)
// Hide the Keyboard
nameTextField.resignFirstResponder()
// UIImagePickerController is a view controller that lets a user pick media from their photo library.
let imagePickerController = UIImagePickerController()
// Only Allow pictures to be selected and not taken
imagePickerController.sourceType = .PhotoLibrary
// make sure the viewcontroller is notified when the user selects an image
imagePickerController.delegate = self
presentViewController(imagePickerController, animated: true, completion: nil)
}
*/
@IBAction func setDefaultLabelText(sender: UIButton) {
mealNameLabel.text = "Default Text"
}
}
回答1:
do like
The reason ,by default the UIImageview userInteraction is false, so you need to enable manually
Step-1
let tapGesture = UITapGestureRecognizer(target:self, action:Selector("imagePressed"))
photoImageView.userInteractionEnabled = true // this line is important
photoImageView.addGestureRecognizer(tapGesture)
Step-2
func imagePressed()
{
//do Your action here whatever you want
}
回答2:
The easiest way I found that solved the issue is to click the checkbox that says "User Interaction Enabled" in the Attributes Editor for the Image View. Screenshot
回答3:
Your code is perfectly fine. The problem is with the UIImageView in the story board. The user interaction option is unchecked.
So you just have to enable this option in storyboard.
Go to your story board.
Select your UIImageView (you named it photoimageview)
Now in “Attribute Inspector” look for
user interaction enabled, it should be “checked”Now run your project it will work.
回答4:
Where have you added the UITapGestureRecognizer for the image view? If you added it in Storyboard, did you connect it to the selector selectImageFromPhotoLibrary:?
来源：https://stackoverflow.com/questions/34984924/ios-tap-gesture-issue-on-image-view