Swift 3 - Pulling images from mySQL database - php

Question

I am currently in the process of designing an application that has a newsfeed. Images and text are stored in our database but I am having trouble pulling the image and displaying it. The code I have should work but I am getting a fatal error saying "THREAD 1: EXC_BAD_INSTRUCTION" around
let imageData = try? Data(contentsOf: url)
let image = UIImage(data: imageData!)!
and the compiler displays this message - "fatal error: unexpectedly found nil while unwrapping an Optional value".
I'm getting the error in this snippet of code:
if!path!.isEmpty {
let url = URL(string: path!)!
let imageData = try? Data(contentsOf: url)
let image = UIImage(data: imageData!)!
self.images.append(image)
} else {
let image = UIImage()
self.images.append(image)
}
Being very new to programming, I've been stuck on this for quite a while now. If there is anything you suggest, let me know! Thanks!
Also, the photo I am trying to retrieve is a .jpg, not sure if that may be important.
(Here's the rest of the code if it is needed)
import UIKit
class SecondViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
var activities = [AnyObject]()
var images = [UIImage]()
#IBOutlet var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
//tableView.contentInset = UIEdgeInsetsMake(2, 0, 0, 0)
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return activities.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "activity", for: indexPath) as! CustomCell
let post = activities[indexPath.row]
let image = images[indexPath.row]
let username = post["username"] as? String
let text = post["text"] as? String
cell.titleLbl.text = text
cell.userLbl.text = username
cell.activityImage.image! = image
//cell.dateLbl.text = activities[indexPath.row]
//cell.activityImage.image = images[indexPath.row]
return cell
}
override func viewWillAppear(_ animated: Bool) {
loadActivities()
}
func loadActivities() {
let id = user!["id"] as! String
let url = URL(string: "https://cgi.soic.indiana.edu/~team7/posts.php")!
var request = URLRequest(url: url)
request.httpMethod = "POST"
let body = "id=\(id)&text=&uuid="
request.httpBody = body.data(using: String.Encoding.utf8)
URLSession.shared.dataTask(with: request) { data, response, error in
DispatchQueue.main.async(execute: {
if error == nil {
do {
let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary
// clean up
self.activities.removeAll(keepingCapacity: false)
self.images.removeAll(keepingCapacity: false)
self.tableView.reloadData()
guard let parseJSON = json else {
print("Error while parsing")
return
}
guard let posts = parseJSON["posts"] as? [AnyObject] else {
print("Error while parseJSONing")
return
}
self.activities = posts
for i in 0 ..< self.activities.count {
let path = self.activities[i]["path"] as? String
if !path!.isEmpty {
let url = URL(string: path!)!
let imageData = try? Data(contentsOf: url)
let image = UIImage(data: imageData!)!
self.images.append(image)
} else {
let image = UIImage()
self.images.append(image)
}
}
self.tableView.reloadData()
} catch {
}
} else {
}
})
}.resume()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
extension NSMutableData {
func appendString(_ string : String) {
let data = string.data(using: String.Encoding.utf8, allowLossyConversion: true)
append(data!)
}
}

Answer 1

Why are you doing all of this ? Get the URLs of the images from your server and then load them asynchronously in cellForRowAtIndexPath using SDWebImage. It is a library you can find it here. https://github.com/rs/SDWebImage. This way you won't need to store your images in an array and it will be faster to load.
Or you can also implement your own async loading of images.

Answer 2

you could try something like this to avoid runtime errors:
if let actualPath = path, !actualPath.isEmpty, let url = URL(string: actualPath) {
if let imageData = try? Data(contentsOf: url) {
if let image = UIImage(data: imageData) {
self.images.append(image)
}
}
}
instead of this
if!path!.isEmpty {
let url = URL(string: path!)!
let imageData = try? Data(contentsOf: url)
let image = UIImage(data: imageData!)!
self.images.append(image)
}