在UIView中对齐UIButton的问题

Question

我试图在我的ViewController中对齐一个UIButton。 我不知道UIButton的具体名称是什么，所以我认为这就是为什么我很难将其作为子视图移动的原因。 这是我的代码：

-(void)viewDidAppear:(BOOL)animated
{
AVCaptureSession *session = [[AVCaptureSession alloc] init];
session.sessionPreset = AVCaptureSessionPresetMedium;

CALayer *viewLayer = self.vImagePreview.layer;
NSLog(@"viewLayer = %@", viewLayer);

AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];

captureVideoPreviewLayer.frame = self.vImagePreview.bounds;
[self.vImagePreview.layer addSublayer:captureVideoPreviewLayer];

//Modify to fit screen

CGAffineTransform translate = CGAffineTransformMakeTranslation(0.0, 0.0);
CGAffineTransform scale = CGAffineTransformMakeScale(1.333333, 1.333333);
CGAffineTransform rotate = CGAffineTransformMakeRotation(DEGREES_RADIANS(180));
CGAffineTransform transform = CGAffineTransformConcat(translate, scale);
transform = CGAffineTransformConcat(transform, rotate);
self.vImagePreview.transform = transform;

[self.vImagePreview sendSubviewToFront:UIButton];

AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

NSError *error = nil;
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
if (!input) {
    // Handle the error appropriately.
    NSLog(@"ERROR: trying to open camera: %@", error);
}
[session addInput:input];

_stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys: AVVideoCodecJPEG, AVVideoCodecKey, nil];
[_stillImageOutput setOutputSettings:outputSettings];
[session addOutput:_stillImageOutput];



[session startRunning];
}

-(IBAction)captureNow {
AVCaptureConnection *videoConnection = nil;
for (AVCaptureConnection *connection in _stillImageOutput.connections)
{
    for (AVCaptureInputPort *port in [connection inputPorts])
    {
        if ([[port mediaType] isEqual:AVMediaTypeVideo] )
        {
            videoConnection = connection;
            break;
        }
    }
    if (videoConnection)
    {
        break;
    }
}

NSLog(@"about to request a capture from: %@", _stillImageOutput);
[_stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error)
 {
     CFDictionaryRef exifAttachments = CMGetAttachment( imageSampleBuffer, kCGImagePropertyExifDictionary, NULL);
     if (exifAttachments)
     {
         // Do something with the attachments.
         NSLog(@"attachements: %@", exifAttachments);
     } else {
         NSLog(@"no attachments");
     }

     NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];
     UIImage *image = [[UIImage alloc] initWithData:imageData];

     self.vImage.image = image;

     //Saved Photo modifications go here

     UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
 }];
}
@end

和我的标题，以防万一：

#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
#import <AVKit/AVKit.h>
#import <ImageIO/CGImageProperties.h>

#define DEGREES_RADIANS(angle) ((angle) / 180.0 * M_PI)

@interface ViewController : UIViewController

@property(nonatomic, retain) IBOutlet UIView *vImagePreview;
@property(nonatomic, retain) AVCaptureStillImageOutput *stillImageOutput;
@property(nonatomic, retain) IBOutlet UIImageView *vImage;

@end

一些澄清：

我的按钮在我的情节提要板上。 该按钮应触发CaptureNow方法，并拍照。 我只是不知道如何使它出现在预览层上。

Answer 1

由于您的UIbutton位于情节提要上，所以不要使用

[self.vImagePreview sendSubviewToFront:UIButton];

使用此行在顶部显示UIBUtton 。

[self.view bringSubviewToFront:UIButton];

在方法结束时开始运行会话之前。