How to take a picture using the proximity sensor? - ios

Question

I am having trouble getting the device to take an image using the rear view camera when the proximity sensor is enabled. I don't want the camera preview to show up, just want the device to take the photo and present it in the imageView. I have the proximity sensor working, and I am using imagePicker.takePicture() to take the image when the proximity sensor is enabled, but that doesn't seem to work. What is the method/function that I can use to programmatically take the picture without the user input.
This is my code so far:
class ViewController: UIViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate {
#IBOutlet var imageView: UIImageView!
var imagePicker: UIImagePickerController!
//*The function in question*
func proximityChanged(notification: NSNotification) {
let device = notification.object as? UIDevice
if device?.proximityState == true {
print("\(device) detected!")

Answer 1

If you have troubles capturing photos with UIImagePickerController, I suggest using AVFoundation.
Below is a working example. Photo capture is triggered by the proximity sensor.
You can add a preview if you need it.
import UIKit
import AVFoundation
final class CaptureViewController: UIViewController {
#IBOutlet weak var imageView: UIImageView!
private static let captureSessionPreset = AVCaptureSessionPresetPhoto
private var captureSession: AVCaptureSession!
private var photoOutput: AVCaptureStillImageOutput!
private var initialized = false
override func viewDidLoad() {
super.viewDidLoad()
initialized = setupCaptureSession()
}
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
if initialized {
captureSession.startRunning()
UIDevice.currentDevice().proximityMonitoringEnabled = true
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(proximityStateDidChange), name: UIDeviceProximityStateDidChangeNotification, object: nil)
}
}
override func viewDidDisappear(animated: Bool) {
super.viewDidDisappear(animated)
if initialized {
NSNotificationCenter.defaultCenter().removeObserver(self, name: UIDeviceProximityStateDidChangeNotification, object: nil)
UIDevice.currentDevice().proximityMonitoringEnabled = false
captureSession.stopRunning()
}
}
dynamic func proximityStateDidChange(notification: NSNotification) {
if UIDevice.currentDevice().proximityState {
captureImage()
}
}
// MARK: - Capture Image
private func captureImage() {
if let c = findConnection() {
photoOutput.captureStillImageAsynchronouslyFromConnection(c) { sampleBuffer, error in
if let jpeg = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(sampleBuffer),
let image = UIImage(data: jpeg)
{
dispatch_async(dispatch_get_main_queue()) { [weak self] in
self?.imageView.image = image
}
}
}
}
}
private func findConnection() -> AVCaptureConnection? {
for c in photoOutput.connections {
let c = c as? AVCaptureConnection
for p in c?.inputPorts ?? [] {
if p.mediaType == AVMediaTypeVideo {
return c
}
}
}
return nil
}
// MARK: - Setup Capture Session
private func setupCaptureSession() -> Bool {
captureSession = AVCaptureSession()
if captureSession.canSetSessionPreset(CaptureViewController.captureSessionPreset) {
captureSession.sessionPreset = CaptureViewController.captureSessionPreset
if setupCaptureSessionInput() && setupCaptureSessionOutput() {
return true
}
}
return false
}
private func setupCaptureSessionInput() -> Bool {
if let captureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo),
let captureDeviceInput = try? AVCaptureDeviceInput.init(device: captureDevice)
{
if captureSession.canAddInput(captureDeviceInput) {
captureSession.addInput(captureDeviceInput)
return true
}
}
return false
}
private func setupCaptureSessionOutput() -> Bool {
photoOutput = AVCaptureStillImageOutput()
photoOutput.outputSettings = [AVVideoCodecKey: AVVideoCodecJPEG]
if captureSession.canAddOutput(photoOutput) {
captureSession.addOutput(photoOutput)
return true
}
return false
}
}