30分钟搞定iOS自定义相机

#import <AVFoundation/AVFoundation.h> 
//捕获设备，通常是前置，后置，麦克风（音频输入）  
@property (nonatomic, strong) AVCaptureDevice *device;  
 
//AVCaptureDeviceInput 代表输入设备，他使用AVCaptureDevice 来初始化  
@property (nonatomic, strong) AVCaptureDeviceInput *input;  
 
//输出图片  
@property (nonatomic ,strong) AVCaptureStillImageOutput *imageOutput;  
 
//session：由他把输入输出结合在一起，并开始启动捕获设备（）  
@property (nonatomic, strong) AVCaptureSession *session;  
 
//图像预览层，实时显示捕获的图像  
@property (nonatomic ,strong) AVCaptureVideoPreviewLayer *previewLayer; 

2、初始化各个对象

- (void)cameraDistrict  
{  
//    AVCaptureDevicePositionBack  后置  
//    AVCaptureDevicePositionFront 前置  

   self.device = [self cameraWithPosition:AVCaptureDevicePositionFront];  


    self.input = [[AVCaptureDeviceInput alloc] initWithDevice:self.device error:nil];  

 

    self.imageOutput = [[AVCaptureStillImageOutput alloc] init];  

 

    self.session = [[AVCaptureSession alloc] init];  

    //     拿到的图像的大小可以自行设定  
    //    AVCaptureSessionPreset320x240  
    //    AVCaptureSessionPreset352x288  
    //    AVCaptureSessionPreset640x480  
    //    AVCaptureSessionPreset960x540  
    //    AVCaptureSessionPreset1280x720  
    //    AVCaptureSessionPreset1920x1080  
    //    AVCaptureSessionPreset3840x2160  

    self.session.sessionPreset = AVCaptureSessionPreset640x480;  

    //输入输出设备结合  
    if ([self.session canAddInput:self.input]) {  
        [self.session addInput:self.input];  
    }  
    if ([self.session canAddOutput:self.imageOutput]) {  
        [self.session addOutput:self.imageOutput];  
    }  
    //预览层的生成  

    self.previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.session];  


    self.previewLayer.frame = CGRectMake(0, 64, SCREEN_WIDTH, SCREEN_HEIGHT-64);  


    self.previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;  

    [self.view.layer addSublayer:self.previewLayer];  
    //设备取景开始  
    [self.session startRunning];  
    if ([_device lockForConfiguration:nil]) {  
    //自动闪光灯，  
        if ([_device isFlashModeSupported:AVCaptureFlashModeAuto]) {  
            [_device setFlashMode:AVCaptureFlashModeAuto];  
        }  
        //自动白平衡,但是好像一直都进不去  
        if ([_device isWhiteBalanceModeSupported:AVCaptureWhiteBalanceModeAutoWhiteBalance]) {  
            [_device setWhiteBalanceMode:AVCaptureWhiteBalanceModeAutoWhiteBalance];  
        }  
        [_device unlockForConfiguration];  
    }  
 
} 

根据前后置位置拿到相应的：

- (AVCaptureDevice *)cameraWithPosition:(AVCaptureDevicePosition)position{  

    NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];  

    for ( AVCaptureDevice *device in devices )  

        if ( device.position == position ){  

            return device;  
        }  
    return nil;  
} 

3、拍照拿到相应图片：

- (void)photoBtnDidClick  
{  

    AVCaptureConnection *conntion = [self.imageOutput connectionWithMediaType:AVMediaTypeVideo];  

      if (!conntion) {  
          NSLog(@"拍照失败!");  
          return;  
          }  
    [self.imageOutput captureStillImageAsynchronouslyFromConnection:conntion completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {  

        if (imageDataSampleBuffer == nil) {  

            return ;  
          }  

        NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];  


        self.image = [UIImage imageWithData:imageData];  

        [self.session stopRunning];  
        [self.view addSubview:self.cameraImageView];  
} 

4、前后置的切换

- (void)changeCamera{  

    NSUInteger cameraCount = [[AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo] count];  


    if (cameraCount > 1) {  

        NSError *error;  
        //给的切换添加翻转  

        CATransition *animation = [CATransition animation]；  


        animation.duration = .5f；  


        animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];  


        animation.type = @"oglFlip";  

 

        AVCaptureDevice *newCamera = nil;  


        AVCaptureDeviceInput *newInput = nil;  

  //拿到另外一个位置  

        AVCaptureDevicePosition position = [[_input device] position];  


        if (position == AVCaptureDevicePositionFront){  


            newCamera = [self cameraWithPosition:AVCaptureDevicePositionBack];  


            animation.subtype = kCATransitionFromLeft;//翻转方向  

        }  
        else {  

            newCamera = [self cameraWithPosition:AVCaptureDevicePositionFront];  


            animation.subtype = kCATransitionFromRight;//翻转方向  

        }  
        //生成新的输入  

        newInput = [AVCaptureDeviceInput deviceInputWithDevice:newCamera error:nil];  

        [self.previewLayer addAnimation:animation forKey:nil];  
        if (newInput != nil) {  
            [self.session beginConfiguration];  
            [self.session removeInput:self.input];  
            if ([self.session canAddInput:newInput]) {  
                [self.session addInput:newInput];  

                self.input = newInput;  

 
            } else {  
                [self.session addInput:self.input];  
            }  
            [self.session commitConfiguration];  
 
        } else if (error) {  

            NSLog(@"toggle carema failed, error = %@", error);  

        }  
    }  
} 

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