Create Animation from Array of images - ios

Question

I am having trouble taking 6 photos and storing them in an object array in order to animate them. I keep getting an error saying:
Array index out of range
Also, I realized that the "image" object isn't recognized outside the if-statement for some reason. What am I doing wrong?
func didPressTakePhoto(){
var picArray: [UIImage] = []
for index in 1...6 {
if let videoConnection = stillImageOutput?.connectionWithMediaType(AVMediaTypeVideo){
videoConnection.videoOrientation = AVCaptureVideoOrientation.Portrait
stillImageOutput?.captureStillImageAsynchronouslyFromConnection(videoConnection, completionHandler: {
(sampleBuffer, error) in
if sampleBuffer != nil {
let imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(sampleBuffer)
let dataProvider = CGDataProviderCreateWithCFData(imageData)
let cgImageRef = CGImageCreateWithJPEGDataProvider(dataProvider, nil, true, CGColorRenderingIntent.RenderingIntentDefault)
let image = UIImage(CGImage: cgImageRef!, scale: 1.0, orientation: UIImageOrientation.Right)
self.tempImageView.image = image
self.tempImageView.hidden = false
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
picArray[index] = image;
}
})
}
}
self.gifView.animationImages = picArray;
self.gifView.animationDuration = 1.0
self.gifView.startAnimating()
}

Answer 1

picArray is empty, so you shouldn't use insert method. instead you have to use the append method.
The reason why is picArray is empty you are inserting the values inside the asynchronous block. The for loop completes before inserting images because it doesn't wait for asynchronous blocks to be complete.
You have to wait for asynchronous block to be complete before animating the image view.
You can achieve this using dispatch_group
func didPressTakePhoto(){
var picArray: [UIImage] = []
let dispatchGroup = dispatch_group_create()
for index in 1...6 {
dispatch_group_enter(dispatchGroup)
if let videoConnection = stillImageOutput?.connectionWithMediaType(AVMediaTypeVideo){
videoConnection.videoOrientation = AVCaptureVideoOrientation.Portrait
stillImageOutput?.captureStillImageAsynchronouslyFromConnection(videoConnection, completionHandler: {
(sampleBuffer, error) in
if sampleBuffer != nil {
let imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(sampleBuffer)
let dataProvider = CGDataProviderCreateWithCFData(imageData)
let cgImageRef = CGImageCreateWithJPEGDataProvider(dataProvider, nil, true, CGColorRenderingIntent.RenderingIntentDefault)
let image = UIImage(CGImage: cgImageRef!, scale: 1.0, orientation: UIImageOrientation.Right)
self.tempImageView.image = image
self.tempImageView.hidden = false
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
picArray.append(image);
}
dispatch_group_leave(dispatchGroup)
})
} else {
dispatch_group_leave(dispatchGroup)
}
}
dispatch_group_notify(dispatchGroup, dispatch_get_main_queue()) {
self.gifView.animationImages = picArray;
self.gifView.animationDuration = 1.0
self.gifView.startAnimating()
}
}
Hope this helps.