iOS taking photo programmatically

问题

I know this is possible, saw this in some apps (iGotYa is I believe the most famous). I know how to set up everything for taking photos, saving it and everything. But how can it be done programmatically? just having the user click some button (in the regular view controller) and it will automatically take a picture using the front camera and saving it (or not, just getting it as a UIImage)

Thanks!

回答1:

This is very simple, just use the AVFoundation reference guide:

https://developer.apple.com/library/ios/#documentation/AudioVideo/Conceptual/AVFoundationPG/Articles/04_MediaCapture.html

If you don't want the user to see the preview input you can just skip the set preview layer part of the code.

Edit: To be more detailed.

1)You set your capture configuration using the AVFoundation.

• Set the camera input to frontal, turn off flash etc etc.

2)You SKIP the part where the video preview layer is set.

3)You call the captureStillImageAsynchronouslyFromConnection:completionHandler: method whenever you want the picture to be taken.

Note: If you want the flash to not be heard and such then you might be violating the user rights in some countries (japan for example). One workaround I know of to do so is by capturing a frame of a video (does not trigger flash).

回答2:

You can also do it without AVFoundation and it is in my opinion an easier way to implement it using only the UIImagePickerController. There are 3 conditions:

1. Obviously the device needs to have a camera
2. You must hide the camera controls
3. Then simply use the takePicture method from UIImagePickerController

Below is a simple example that you woul typically trigger after a button push

- (IBAction)takePhoto:(id)sender 
{
    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    picker.delegate = self;
    picker.sourceType = UIImagePickerControllerSourceTypeCamera;
    picker.cameraDevice = UIImagePickerControllerCameraDeviceFront;
    picker.showsCameraControls = NO;
    [self presentViewController:picker animated:YES
                     completion:^ {
                         [picker takePicture];
                     }];
}

回答3:

VLBCameraView is a library that uses AVFoundation to take photo.

A preview is shown in the view, which you can then call the method VLBCameraView#takePicture programmatically to take a photo.

Comes with CocoaPods.

回答4:

In .h file

@interface ABCViewController : UIViewController

@property (strong, nonatomic) IBOutlet UIImageView *imageView;

- (IBAction)takePhoto:  (UIButton *)sender;
- (IBAction)selectPhoto:(UIButton *)sender;

@end

In .m file

@interface ABCViewController : UIViewController <UIImagePickerControllerDelegate, UINavigationControllerDelegate>

- (IBAction)takePhoto:(UIButton *)sender {


if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {

        UIAlertView *myAlertView = [[UIAlertView alloc] initWithTitle:@"Error"
                                                        message:@"Device has no camera"
                                                        delegate:nil
                                                        cancelButtonTitle:@"OK"
                                                        otherButtonTitles: nil];

        [myAlertView show];

    } else {

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

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

}

}

- (IBAction)selectPhoto:(UIButton *)sender {

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

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


}

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

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

    [picker dismissViewControllerAnimated:YES completion:NULL];

}


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

    [picker dismissViewControllerAnimated:YES completion:NULL];

}

回答5:

Here is the code for Objective -C Custom Camera. You can add features, buttons according to your wish.

#import "CustomCameraVC.h"

@interface CustomCameraVC ()  {
    BOOL frontCamera;
}
@property (strong,nonatomic) AVCaptureSession *captureSession;
@property (strong,nonatomic) AVCaptureStillImageOutput *stillImageOutput;
@property (strong,nonatomic) AVCaptureVideoPreviewLayer *videoPreviewLayer;
@property (weak, nonatomic) IBOutlet UIView *viewCamera;


@end

@implementation CustomCameraVC

- (void)viewDidLoad {
    [super viewDidLoad];        
}

-(void)viewWillAppear:(BOOL)animated  {
    [super viewWillAppear:YES];
    frontCamera = NO;
    [self showCameraWithFrontCamera:frontCamera];

}

-(void)showCameraWithFrontCamera:(BOOL)flag {
    self.captureSession = [[AVCaptureSession alloc]init];
    self.captureSession.sessionPreset = AVCaptureSessionPresetPhoto;
    AVCaptureDevice *captureDevice;
    if(flag)  {
      captureDevice= [self frontCamera];
    }
    else {
      captureDevice= [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    }
    NSError *error = nil;
    AVCaptureDeviceInput *input =   [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];

    [self.captureSession addInput:input];
    self.stillImageOutput = [AVCaptureStillImageOutput new];
    self.stillImageOutput.outputSettings = @{AVVideoCodecKey:AVVideoCodecJPEG};
    [self.captureSession addOutput:_stillImageOutput];
    self.videoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.captureSession];

    self.videoPreviewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
    self.videoPreviewLayer.connection.videoOrientation = AVCaptureVideoOrientationPortrait;
    [self.viewCamera.layer addSublayer:self.videoPreviewLayer];
    [self.captureSession startRunning];
    self.videoPreviewLayer.frame = self.viewCamera.bounds;
}


- (AVCaptureDevice *)frontCamera {
    NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    for (AVCaptureDevice *device in devices) {
        if ([device position] == AVCaptureDevicePositionFront) {
            return device;
        }
    }
    return nil;
}


- (IBAction)btnCaptureImagePressed:(id)sender {

     AVCaptureConnection * videoConnection =  [_stillImageOutput connectionWithMediaType:AVMediaTypeVideo];

    [_stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler:^(CMSampleBufferRef  _Nullable sampleBuffer, NSError * _Nullable error) {
       NSData *imageData =  [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:sampleBuffer];
        UIImage *image = [[UIImage alloc]initWithData: imageData];
        UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
    }];

}

@end

来源：https://stackoverflow.com/questions/9694859/ios-taking-photo-programmatically