问题
I am currently approaching Swift (I have been coding in Objective-C for some years) and I am trying to develop a companion app to my video-surveillance system.
What my app do is:
- Connect to a password-protected web site and obtain a list of the last snapshots uploaded by either one of the three existing ip-cameras.
- For each of these shots, I create a PicInfo object with a temporary pic. I then attempt to asynchronously download the pics and store them in an UIImage property.
- From there, I have prototype cells in my MasterViewController with a few details. Touching one will segue me to a bigger view in the DetailViewController.
I also implemented a refresh where I'd reload the complete list and replace the last 100 table cells and the contents of the NSMutable array.
Current issues:
- After the initial load, the Master Table View appears empty until I lightly touch it.
- Although the NSLog^Wprintln statements shows that the list was successfully reloaded, the table won't refresh and it will still show the waiting widget...
- I get someunaesthetical "bad packing" errors while putting NSData in my UIImages (or so I think: the mssage is not more explicit) which otherwise display fine.
What am I doing wrong?
PicInfo.swift
import Foundation
import UIKit
class PicInfo {
var index: Int = 0
var description: String = ""
var stamp: String = ""
var url: String = ""
var image: UIImage!
var downloaded: Bool = false;
var downloading: Bool = false;
init(data: String) {
var picInfos=data.componentsSeparatedByString("\t")
println("found: \(picInfos[0]): [\(picInfos[2])] taken at \(picInfos[1])")
self.index = picInfos[0].toInt()!
self.url = baseUrlString + "/" + picInfos[2]
self.stamp = picInfos[1]
description = ""
if (picInfos[2].rangeOfString("HALLCAM") != nil) {
description="Hall"
} else if (picInfos[2].rangeOfString("STAIRSCAM") != nil) {
description="Garden"
} else {
description="Cats"
}
self.image = UIImage(named: "nothingyet")
self.loadImage()
}
func URL() -> NSURL {
var URL=NSURL(string: self.url)
return URL!
}
func loadImage() {
if (self.downloading) {
return
}
let url = self.URL()
let request = NSMutableURLRequest(URL: url)
let loginString = NSString(format: "%@:%@", username, password)
let loginData: NSData = loginString.dataUsingEncoding(NSUTF8StringEncoding)!
let base64LoginString = loginData.base64EncodedStringWithOptions(nil)
// create the request
request.HTTPMethod = "POST"
request.setValue("Basic \(base64LoginString)", forHTTPHeaderField: "Authorization")
self.downloading = true
NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue(), completionHandler: {(response: NSURLResponse!,data: NSData!,error: NSError!) -> Void in
if error == nil {
if let blob = data {
self.image = UIImage(data: data)
self.downloaded = true
}
}
else {
println("Error: \(error.localizedDescription)")
}
self.downloading = false
})
}
}
MasterViewController.swift
import UIKit
let baseUrlString = "http://my.domain.net"
let username = "OoOoOoOoO"
let password = "xXxXxXxXx"
class MasterViewController: UITableViewController,NSURLConnectionDataDelegate{
var detailViewController: DetailViewController!
var objects = NSMutableArray()
var loading: Bool = false;
override func awakeFromNib() {
super.awakeFromNib()
if UIDevice.currentDevice().userInterfaceIdiom == .Pad {
self.clearsSelectionOnViewWillAppear = false
self.preferredContentSize = CGSize(width: 320.0, height: 600.0)
}
}
override func viewDidLoad() {
super.viewDidLoad()
if let split = self.splitViewController {
let controllers = split.viewControllers
self.detailViewController = controllers[controllers.count-1].topViewController as? DetailViewController
self.detailViewController.picInfos = self.objects;
}
self.refreshControl?.addTarget(self, action: "refresh:", forControlEvents: UIControlEvents.ValueChanged)
self.loadPictureList()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func insertNewObject(data: String) {
var picInfo=PicInfo(data: data)
objects.insertObject(picInfo, atIndex: picInfo.index)
let indexPath = NSIndexPath(forRow: picInfo.index, inSection: 0)
self.tableView.insertRowsAtIndexPaths([indexPath], withRowAnimation: .Automatic)
}
// MARK: - Segues
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "showDetail" {
if let indexPath = self.tableView.indexPathForSelectedRow() {
let object = objects[indexPath.row] as PicInfo
println("following segue: \(indexPath.row) => \(object.index)")
let controller = (segue.destinationViewController as UINavigationController).topViewController as DetailViewController
controller.detailItem = object
controller.navigationItem.leftBarButtonItem = self.splitViewController?.displayModeButtonItem()
controller.navigationItem.leftItemsSupplementBackButton = true
}
}
}
// MARK: - Table View
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return objects.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell
if let object = objects[indexPath.row] as? PicInfo {
var todo=""
if (object.downloading || !object.downloaded) {
todo="(*)"
}
cell.textLabel!.text = "\(object.index): \(object.description)\(todo)"
cell.detailTextLabel?.text = object.stamp
if (!object.downloaded) {
object.loadImage()
}
cell.imageView?.image = object.image
}
return cell
}
override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
// Return false if you do not want the specified item to be editable.
return false
}
// MARK: - Refresh
func refresh(sender:AnyObject)
{
// Updating your data here...
self.loadPictureList()
}
// MARK: Internet stuff
func loadPictureList () {
// set up the base64-encoded credentials
if (self.loading) {
return
}
self.loading = true
let config = NSURLSessionConfiguration.defaultSessionConfiguration()
let loginString = NSString(format: "%@:%@", username, password)
let loginData: NSData = loginString.dataUsingEncoding(NSUTF8StringEncoding)!
let base64LoginString = loginData.base64EncodedStringWithOptions(nil)
let authString = "Basic \(base64LoginString)"
config.HTTPAdditionalHeaders = ["Authorization" : authString]
let session = NSURLSession(configuration: config)
// create the request
let url = NSURL(string: baseUrlString + "/latest.php")
let request = NSMutableURLRequest(URL: url!)
// fire off the request
var task = session.dataTaskWithURL(url!){
(data, response, error) -> Void in
if error != nil {
self.handlePictureList("", encounteredProblem:"\(error.localizedDescription)\nurl:\(url)")
} else {
var result = NSString(data: data, encoding: NSASCIIStringEncoding)!
self.handlePictureList(result, encounteredProblem:"")
}
}
task.resume()
}
func handlePictureList (data: NSString, encounteredProblem error: NSString) {
if (error.length>0) {
println ("Had error: [\(error)]")
} else {
println ("Got data!")
println("Refresh will start")
self.tableView.beginUpdates()
for o in objects {
let p = o as PicInfo
var i=NSIndexPath(forRow: p.index, inSection: 0)
self.tableView.deleteRowsAtIndexPaths([i], withRowAnimation: UITableViewRowAnimation.Fade)
objects.removeObject(o)
}
var pixArr = data.componentsSeparatedByString("\n")
for unparsedPicInfo in pixArr {
if (unparsedPicInfo.hasPrefix("<tr>")) {
var picInfo=unparsedPicInfo.stringByReplacingOccurrencesOfString("<tr><td>", withString: "")
picInfo=picInfo.stringByReplacingOccurrencesOfString("</td></tr>", withString: "")
picInfo=picInfo.stringByReplacingOccurrencesOfString("</td><td>", withString: "\t")
self.insertNewObject(picInfo)
}
}
self.loading = false
self.tableView.endUpdates()
self.tableView.reloadData()
println("Refresh is over")
}
return
}
}
DetailViewController.swift
import UIKit
class DetailViewController: UIViewController {
@IBOutlet weak var detailDescriptionLabel: UILabel!
@IBOutlet weak var pictureView: UIImageView!
@IBOutlet weak var progressView: UIProgressView!
var picInfos: NSMutableArray!
var detailItem: AnyObject? {
didSet {
// Update the view.
if let detail = detailItem as? PicInfo {
println("Preparing to display object#\(detail.index)")
} else {
println("Bizarre?!")
}
self.configureView()
}
}
func configureView() {
// Update the user interface for the detail item.
if let detail = detailItem as? PicInfo {
if let label = self.detailDescriptionLabel {
var todo=""
if (detail.downloading || !detail.downloaded) {
todo="(*)"
}
label.text = "\(detail.index): \(detail.description)\(todo)"
}
self.title = detail.stamp
if let proVi = self.progressView {
if let pi = self.picInfos {
var total = pi.count
if ( total==0 ) {
total=1
}
proVi.setProgress( Float(Double(detail.index) / Double(total)), animated: true)
}
}
if let img = self.pictureView {
if (!detail.downloaded) {
detail.loadImage()
}
img.image = detail.image
}
}
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.configureView()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
Thanks in advance for your help.
回答1:
I switched to CoreData in order to gain some flexibility.
来源：https://stackoverflow.com/questions/28623920/uitableview-refresh-problems-with-an-nsurlconnection-asynchronously-laden-nsmuta