问题
I am trying to make a simple "Profile" view that allows the user to change his picture. the image picker loads the gallery successfully and i choose the new image then write it to documents directory to load it in next launch, the problem is the imageview is not refreshing with the new image until i exit the app and relaunch again (only viewDidLoad works but viewWillAppear is loading the old image although it is overwritten!) any ideas?
import UIKit
class Profile: UIViewController,UIImagePickerControllerDelegate,UINavigationControllerDelegate {
var imagePicker:UIImagePickerController=UIImagePickerController()
var pickedImage:UIImage?
let filemgr = NSFileManager.defaultManager()
@IBOutlet weak var profilepic: UIImageView!
@IBOutlet weak var lblheight: UILabel!
@IBOutlet weak var lblwidth: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
profilepic.layer.borderWidth=1
profilepic.layer.borderColor=UIColor.blackColor().CGColor
let tapGestureRecognizer = UITapGestureRecognizer(target:self, action:Selector("imageTapped:"))
profilepic.userInteractionEnabled = true
profilepic.addGestureRecognizer(tapGestureRecognizer)
imagePicker.delegate=self
if profileImageExists()
{
pickedImage=UIImage(named: Operations.getDocumentsDirectory().stringByAppendingPathComponent("profile.png"))!
} else {
pickedImage=UIImage(named:"camera.png")!
}
profilepic.image=pickedImage
}
func imageTapped(img: AnyObject)
{
imagePicker.allowsEditing = false
imagePicker.sourceType = .PhotoLibrary
presentViewController(imagePicker, animated: true, completion:
{
self.lblheight.text="completed"
print ("completed image tab")
}
)
}
override func viewWillAppear(animated: Bool) {
pickedImage=UIImage(named: Operations.getDocumentsDirectory().stringByAppendingPathComponent("profile.png"))!
profilepic.image=pickedImage
}
// MARK: - UIImagePickerControllerDelegate Methods
func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
profilepic.contentMode = .ScaleToFill
profilepic.image = pickedImage
if let data = UIImagePNGRepresentation(pickedImage) {
let filename = Operations.getDocumentsDirectory().stringByAppendingPathComponent("profile.png")
data.writeToFile(filename, atomically: true)
}
}
dismissViewControllerAnimated(true, completion: nil)
}
func profileImageExists() -> Bool
{
if let profileImage=UIImage(named: Operations.getDocumentsDirectory().stringByAppendingPathComponent("profile.png"))
{
return true
}
else
{
return false
}
}
}
回答1:
Loading an UIImage with init(named:) caches the image. So as long as the image name does not change or the system is emptying the cache (for example when you restart the app) the image will be used from the cache and not loaded again.
Try to use init(contentsOfFile:) instead to load the image.
回答2:
Try updating your imagePickerController method. You have used pickedImage as an instance variable and an local optional variable. I have used newImage instead.
func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
if let newImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
profilepic.contentMode = .ScaleToFill
profilepic.image = newImage
pickedImage = newImage
if let data = UIImagePNGRepresentation(newImage) {
let filename = Operations.getDocumentsDirectory().stringByAppendingPathComponent("profile.png")
data.writeToFile(filename, atomically: true)
}
}
dismissViewControllerAnimated(true, completion: nil)
}
来源：https://stackoverflow.com/questions/34512918/uiimageview-not-updating-image