How to allow the user to pick a photo from his camera roll or photo library?

I'm making a little photo editing app for fun. Users must select a photo from their camera roll which will then be imported for modification.

How does this generally work? I have seen many apps allowing this with a standard controller that looks always the same.

Is it also possible to acce开发者_如何学编程ss this library directly or to customize the appearance of that controller?

Where should I start looking?

The easiest way to do this is by using the UIImagePickerController in a simple alertView.

For example, you want someone to tap on their profile picture and be able to set a new image from either their camera or their photo library.

@IBAction func btnProfilePicTap(sender: AnyObject) {
    let picker = UIImagePickerController()
    picker.delegate = self
    let alert = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet)
    alert.addAction(UIAlertAction(title: "Camera", style: .default, handler: {
        action in
        picker.sourceType = .camera
        self.present(picker, animated: true, completion: nil)
    }))
    alert.addAction(UIAlertAction(title: "Photo Library", style: .default, handler: {
        action in
        picker.sourceType = .photoLibrary
        self.present(picker, animated: true, completion: nil)
    }))
    alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
    self.present(alert, animated: true, completion: nil)
}

Then simply add the delegate and you're done.

extension ProfileViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    func imagePickerController(picker: UIImagePickerController, didFinishPickingImage image: UIImage!, editingInfo: [NSObject : AnyObject]!) {
        //use image here!
        dismiss(animated: true, completion: nil)
    }

    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        dismiss(animated: true, completion: nil)
    }
}

Sorry, this example is in swift but I hope it still helps.

EDIT: Updated for Swift 5.

I worked on an application that allows user to select a personal image. I had two UIButtons which could help the user to pick a picture, whether it was from camera or library. It's something like this:

- (void)camera {
if(![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]){
    return;
}
UIImagePickerController *picker = [[[UIImagePickerController alloc] init] autorelease];
picker.sourceType = UIImagePickerControllerSourceTypeCamera;
//Permetto la modifica delle foto
picker.allowsEditing = YES;
//Imposto il delegato
[picker setDelegate:self];

[self presentModalViewController:picker animated:YES];
}
- (void)library {
//Inizializzo la classe per la gestione della libreria immagine
UIImagePickerController *picker = [[[UIImagePickerController alloc] init] autorelease];
picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
//Permetto la modifica delle foto
picker.allowsEditing = YES;
//Imposto il delegato
[picker setDelegate:self];

[self presentModalViewController:picker animated:YES];
}

You have to implement the UIImagePickerControllerDelegate:

@interface PickPictureViewController : UIViewController <UIImagePickerControllerDelegate>

@implementation PickPictureViewController

#pragma mark UIImagePickerController Delegate
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{
UIImage *pickedImage = [info objectForKey:UIImagePickerControllerEditedImage];
if (picker.sourceType == UIImagePickerControllerSourceTypeCamera) {
    UIImageWriteToSavedPhotosAlbum(pickedImage, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
}
[self dismissModalViewControllerAnimated:YES];
}
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{
[self dismissModalViewControllerAnimated:YES];
}
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo{}

Hope it helps! ;)

This answer relevant on physical device ONLY!

Access Camera:

- (void)takePhoto {

UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.delegate = self;
picker.allowsEditing = YES;
picker.sourceType = UIImagePickerControllerSourceTypeCamera;

[self presentViewController:picker animated:YES completion:NULL];

}

Access Camera Roll:

- (void)selectPhoto {

UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.delegate = self;
picker.allowsEditing = YES;
picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

[self presentViewController:picker animated:YES completion:NULL];


}

Implementing the Delegate Methods of UIImagePickerController:

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

UIImage *chosenImage = info[UIImagePickerControllerEditedImage];
self.imageView.image = chosenImage;

[picker dismissViewControllerAnimated:YES completion:NULL];

}

And This:

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {

[picker dismissViewControllerAnimated:YES completion:NULL];

}

Also check for more info on this link

SWIFT 2.0

Thanks to William T. this worked for my on my UITapGestureRecognizer

func selectPhoto(tap: UITapGestureRecognizer) {
    let picker = UIImagePickerController()
    picker.delegate = self
    let alert = UIAlertController(title: nil, message: nil, preferredStyle: .ActionSheet)
    alert.addAction(UIAlertAction(title: "Camera", style: .Default, handler: {
        action in
        picker.sourceType = .Camera
        picker.allowsEditing = true
        self.presentViewController(picker, animated: true, completion: nil)
    }))
    alert.addAction(UIAlertAction(title: "Photo Library", style: .Default, handler: {
        action in
        picker.sourceType = .PhotoLibrary
        picker.allowsEditing = true
        self.presentViewController(picker, animated: true, completion: nil)
    }))
    alert.addAction(UIAlertAction(title: "Cancel", style: .Cancel, handler: nil))
    self.presentViewController(alert, animated: true, completion: nil)
}

I added the following to let me edit the photo after selecting it to both the .Camera and .PhotoLibrary:

picker.allowsEditing = true

Take a look at UIImagePickerController

@WilliamT 's answer worked really well for me. Here is his, but updated for Swift 4 in case anyone is still looking for this.

This goes into the view controller class block that contains the button that you want to trigger the camera/image picker.

@IBAction func YourButtonToTriggerCamera/ImagePicker(_ sender: UIButton) {
    let picker = UIImagePickerController()
    picker.delegate = (self as UIImagePickerControllerDelegate & UINavigationControllerDelegate)
    let alert = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet)
    alert.addAction(UIAlertAction(title: "Camera", style: .default, handler: {
        action in
        picker.sourceType = .camera
        self.present(picker, animated: true, completion: nil)
    }))
    alert.addAction(UIAlertAction(title: "Photo Library", style: .default, handler: {
        action in
        picker.sourceType = .photoLibrary
        self.present(picker, animated: true, completion: nil)
    }))
    alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
    self.present(alert, animated: true, completion: nil)
}

This goes below your View Controller Class:

extension YourViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {

    func imagePickerController(picker: UIImagePickerController, didFinishPickingImage image: UIImage!, editingInfo: [NSObject : AnyObject]!) {
        //use image here!
        dismiss(animated: true, completion: nil)
    }

    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        dismiss(animated: true, completion: nil)
    }
}

Here is an example app and a wrapper that gives you the Take Photo or Select from Library just like Facebook does. https://github.com/fulldecent/FDTake