我的应用从网址中检索图片，但我需要在 tableview 中的用户界面上显示之前更改图片大小。
这是我的tableViewController代码：
import UIKit
import Firebase
import Alamofire
class FeedViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, UIImagePickerControllerDelegate, UINavigationControllerDelegate, UITextFieldDelegate {
@IBOutlet weak var tableView: UITableView!
@IBOutlet weak var postField: MaterialTextField!
@IBOutlet weak var imageSelectorImage: UIImageView!
var posts = [Post]()
var imageSelected = false
var imagePicker: UIImagePickerController!
static var imageCache = NSCache()
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
postField.delegate = self
//tableView.estimatedRowHeight = 400
//tableView.rowHeight = UITableViewAutomaticDimension
imagePicker = UIImagePickerController()
imagePicker.delegate = self
DataService.ds.REF_POSTS.queryOrderedByChild("timestamp").observeEventType(.Value, withBlock: { snapshot in
self.posts = []
if let snapshots = snapshot.children.allObjects as? [FDataSnapshot] {
for snap in snapshots {
if let postDict = snap.value as? Dictionary<String, AnyObject> {
let key = snap.key
let post = Post(postKey: key, dictionary: postDict)
self.posts.insert(post, atIndex: 0)
}
}
}
self.tableView.reloadData()
})
}
func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
/**
* Called when the user click on the view (outside the UITextField).
*/
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
self.view.endEditing(true)
}
func textFieldDidBeginEditing(textField: UITextField) {
animateViewMoving(true, moveValue: 167)
}
func textFieldDidEndEditing(textField: UITextField) {
animateViewMoving(false, moveValue: 167)
}
func animateViewMoving (up:Bool, moveValue :CGFloat){
let movementDuration:NSTimeInterval = 0.1
let movement:CGFloat = ( up ? -moveValue : moveValue)
UIView.beginAnimations( "animateView", context: nil)
UIView.setAnimationBeginsFromCurrentState(true)
UIView.setAnimationDuration(movementDuration )
self.view.frame = CGRectOffset(self.view.frame, 0, movement)
UIView.commitAnimations()
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return posts.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let post = posts[indexPath.row]
print(post.postDescription)
if let cell = tableView.dequeueReusableCellWithIdentifier("PostCell") as? PostCell {
cell.request?.cancel()
var img: UIImage?
if let url = post.imageUrl {
img = FeedViewController.imageCache.objectForKey(url) as? UIImage
}
cell.configureCell(post, img: img)
return cell
} else {
return PostCell()
}
}
func imagePickerController(picker: UIImagePickerController, didFinishPickingImage image: UIImage, editingInfo: [String : AnyObject]?) {
imagePicker.dismissViewControllerAnimated(true, completion: nil)
imageSelectorImage.image = image
imageSelected = true
}
@IBAction func selectImage(sender: UITapGestureRecognizer) {
presentViewController(imagePicker, animated: true, completion: nil)
}
@IBAction func makePost(sender: AnyObject) {
//TODO: Add loading spinner while data is being processed
if let txt = postField.text where txt != "" {
if let img = imageSelectorImage.image where imageSelected == true {
let urlStr = URL_IMGSHACK
let url = NSURL(string: urlStr)!
//FIXME: Add error handling
let imgData = UIImageJPEGRepresentation(img, 0.2)!
let keyData = API_KEY_IMG.dataUsingEncoding(NSUTF8StringEncoding)!
let keyJSON = "json".dataUsingEncoding(NSUTF8StringEncoding)!
Alamofire.upload(.POST, url, multipartFormData: { multipartFormData in
multipartFormData.appendBodyPart(data: imgData, name: "fileupload", fileName: "image",
mimeType: "image/jpg")
multipartFormData.appendBodyPart(data: keyData, name: "key")
multipartFormData.appendBodyPart(data: keyJSON, name: "format")
}) { encodingResult in
switch encodingResult {
case .Success(let upload, _, _):
upload.responseJSON(completionHandler: { response in
if let info = response.result.value as? Dictionary<String, AnyObject> {
if let links = info["links"] as? Dictionary<String, AnyObject>{
if let imgLink = links["image_link"] as? String {
print("LINK: \(imgLink)")
self.postToFirebase(imgLink)
}
}
}
})
case .Failure(let error):
print(error)
}
}
} else {
self.postToFirebase(nil)
}
}
}
func postToFirebase(imgUrl: String?) {
var post: Dictionary<String, AnyObject> = [
"timestamp": NSNumber(longLong: currentTimeMillis()),
"description": postField.text!,
"likes": 0
]
if imgUrl != nil {
post["imageUrl"] = imgUrl!
}
let firebasePost = DataService.ds.REF_POSTS.childByAutoId()
firebasePost.setValue(post)
postField.text = ""
imageSelectorImage.image = UIImage(named: "camera")
imageSelected = false
tableView.reloadData()
postField.resignFirstResponder()
}
func currentTimeMillis() ->Int64 {
let nowDouble = NSDate().timeIntervalSince1970
return Int64(nowDouble * 1000)
}
}
这是我的自定义单元格：
class PostCell: UITableViewCell {
@IBOutlet weak var profileImage: UIImageView!
@IBOutlet weak var showcaseImage: UIImageView!
@IBOutlet weak var descriptionText: UILabel!
@IBOutlet weak var likesLabel: UILabel!
@IBOutlet weak var likeImage: UIImageView!
var post: Post!
var request: Request?
var likeRef: Firebase!
override func awakeFromNib() {
super.awakeFromNib()
let tap = UITapGestureRecognizer(target: self, action: "likeTapped:")
tap.numberOfTapsRequired = 1
likeImage.addGestureRecognizer(tap)
likeImage.userInteractionEnabled = true
}
override func drawRect(rect: CGRect) {
profileImage.layer.cornerRadius = self.profileImage.frame.size.width / 2
profileImage.backgroundColor = UIColor.clearColor()
profileImage.layer.borderWidth = 2
profileImage.layer.borderColor = UIColor.whiteColor().CGColor
self.profileImage.clipsToBounds = true
self.showcaseImage.clipsToBounds = true
}
func configureCell(post: Post, img: UIImage?){
self.post = post
likeRef = DataService.ds.REF_USERS_CURRENT.childByAppendingPath("likes").childByAppendingPath(post.postKey)
self.descriptionText.text = post.postDescription
self.likesLabel.text = "\(post.likes)"
if post.imageUrl != nil {
if img != nil {
self.showcaseImage.image = img
} else {
request = Alamofire.request(.GET, post.imageUrl!).validate(contentType: ["image/*"]).response(completionHandler: { request, response, data, err in
if err == nil {
let img = UIImage(data: data!)!
self.showcaseImage.image = img
FeedViewController.imageCache.setObject(img, forKey: self.post.imageUrl!)
} else {
print(err.debugDescription)
}
})
}
} else {
self.showcaseImage.hidden = true
}
likeRef.observeSingleEventOfType(.Value, withBlock: { snapshot in
if let doesNotExist = snapshot.value as?
NSNull {
//This mean we have not liked this specific post
self.likeImage.image = UIImage(named: "heart-empty")
} else {
self.likeImage.image = UIImage(named: "heart-full")
}
})
}
func likeTapped(sender: UITapGestureRecognizer) {
likeRef.observeSingleEventOfType(.Value, withBlock: { snapshot in
if let doesNotExist = snapshot.value as?
NSNull {
self.likeImage.image = UIImage(named: "heart-full")
self.post.adjustLikes(true)
self.likeRef.setValue(true)
} else {
self.likeImage.image = UIImage(named: "heart-empty")
self.post.adjustLikes(false)
self.likeRef.removeValue()
}
})
}
}
这是一个展示我想要实现的目标的例子：
this when user post the portrait image
this when user post the landscape image
总之，我希望图像宽度适合设备屏幕的宽度，以及uiimage的动态高度，无论图像方向如何（横向或纵向）。
答案 0 :(得分：0)
尝试此部件，其中需要300x600尺寸的图像才能保存。
let image = UIImage(data: data!)
UIGraphicsBeginImageContext(CGSizeMake(300, 600))
image?.drawInRect(CGRectMake(0, 0, 300, 600))
let smallImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()