I defined var postImgData = [UIImage]() at beginning of class to store all the images get from sever. The following is the code to get the image from sever
func loadPosts(){
let query = PFQuery(className: "posts")
query.whereKey("username", equalTo:PFUser.current()!.username!)
query.skip = self.picArray.count // skip the already loaded images
query.findObjectsInBackground { (objects, error) in
if error == nil {
if let objects = objects{
for object in objects{
self.collectionView?.performBatchUpdates({
let indexPath = IndexPath(row: self.uuidArray.count, section: 0)
self.uuidArray.append(object.value(forKey: "uuid") as! String)
self.picArray.append(object.value(forKey: "pic") as! PFFile)
self.collectionView?.insertItems(at: [indexPath])
}, completion: nil)
}
}
} else{
print(error!.localizedDescription)
}
}
}
Then i want to use self.postImgData[indexPath.row] = UIImage(data: data!)! to save each image data into postImgData array that defined earlier. But when i run the app it gives error said this line self.postImgData[indexPath.row] = UIImage(data: data!)! Thread 1: Fatal error: Index out of range. I am not sure why its happening? I tried use append function and its working but its didn't show the correct photo when i selected each cell. I am note sure what is correct way to do that? thanks
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return picArray.count
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
//define cell
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! pictureCell
picArray[indexPath.row].getDataInBackground { (data, error) in
if error == nil {
cell.picImg.image = UIImage(data: data!)
self.postImgData[indexPath.row] = UIImage(data: data!)!
} else {
print(error!.localizedDescription)
}
}
return cell
}