iOS自定义相机功能

#import <Foundation/Foundation.h>
#import <AVFoundation/AVFoundation.h>
//拍照后的回调，传递拍摄的照片
typedef void(^DidCapturePhotoBlock)(UIImage *stillImage);

@interface PXCameraManager : NSObject

@property (nonatomic, strong) AVCaptureSession *session;//AVCaptureSession对象来执行输入设备和输出设备之间的数据传递

@property (nonatomic, strong) AVCaptureVideoPreviewLayer *previewLayer;//预览图层，来显示照相机拍摄到的画面

@property (nonatomic, strong) AVCaptureDeviceInput *deviceInput;//AVCaptureDeviceInput对象是输入流

@property (nonatomic, strong) AVCaptureStillImageOutput *stillImageOutput;//照片输出流对象

@property (nonatomic, assign) CGRect previewLayerFrame;//拍照区域

/* 为其他类提供的自定义接口 */

//设置拍照区域 (其中targetView为要展示拍照界面的view)
- (void)configureWithtargetViewLayer:(UIView *)targetView previewRect:(CGRect)preivewRect;

//拍照成功回调
- (void)takePicture:(DidCapturePhotoBlock)block;

//添加/移除相机浮层（如果有需求要在相机拍照区域添加浮层的时候使用）
- (void)addCoverImageWithImage:(UIImage *)image;
- (void)removeCoverImageWithImage:(UIImage *)image;

//前后摄像头切换
- (void)switchCameras;

//闪光灯切换
- (void)configCameraFlashlight;


@end

@property (nonatomic, strong) UIView *preview;//展现拍照区域的view
@property (nonatomic, strong) UIImageView *coverImageView;//拍照区域浮层

@property (nonatomic, assign) BOOL isCaremaBack;
@property (nonatomic, assign) AVCaptureFlashMode flashMode;

//初始化的时候设置自己想要的默认属性
- (instancetype)init{

    self = [super init];
    if (self) {

        self.isCaremaBack = YES;//默认后置摄像头
        self.flashMode = AVCaptureFlashModeAuto;//默认自动闪光灯
    }
    return  self;
}

- (void)configureWithTargetViewLayer:(UIView *)targetView previewRect:(CGRect)preivewRect{

    self.preview = targetView;

    //开始一些相机相关硬件配置    
    [self addSession];//创建session

    [self addVideoPreviewLayerWithRect:preivewRect];//用session 创建 创建layer

    [self addvideoInputBackCamera:self.isCaremaBack];//给session 配置摄像头

    [self addVideoFlashlightWithFlashModel:self.flashMode];//配置闪光灯

    [self addStillImageOutput];//给session 配置输出
}

#pragma mark - 
- (void)takePicture:(DidCapturePhotoBlock)block{

    AVCaptureConnection *captureConnection = [self findCaptureConnection];

    [captureConnection setVideoScaleAndCropFactor:1.0f];

    [_stillImageOutput captureStillImageAsynchronouslyFromConnection:captureConnection completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {

        NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];

        UIImage *image = [UIImage imageWithData:imageData]；
        //这里可以根据不同需求对拍摄到的照片做一些压缩或者裁剪的处理，这里我就偷懒不弄了。
        if (block) {
            block(image);
        }
    }];

}

- (void)switchCameras{
    if (!_deviceInput) {
        return;
    }
    [_session beginConfiguration];

    [_session removeInput:_deviceInput];
    self.isCaremaBack = !self.isCaremaBack;
    [self addvideoInputBackCamera:self.isCaremaBack];

    [_session commitConfiguration];
}

- (void)configCameraFlashlight{

    switch (self.flashMode) {
        case AVCaptureFlashModeAuto:
        {
            self.flashMode = AVCaptureFlashModeOff;
        }
            break;
        case AVCaptureFlashModeOff:
        {
            self.flashMode = AVCaptureFlashModeOn;
        }
            break;
        case AVCaptureFlashModeOn:
        {
            self.flashMode = AVCaptureFlashModeAuto;
        }
            break;
        default:
            break;
    }

    [self addVideoFlashlightWithFlashModel:self.flashMode];

 }

- (void)addCoverImageWithImage:(UIImage *)image{

    _coverImageView.image = image;
}
- (void)removeCoverImageWithImage:(UIImage *)image{

    _coverImageView.image = nil;

}

- (void)addSession{

    if (!self.session) {
        AVCaptureSession *session = [[AVCaptureSession alloc]init];
        self.session = session;
    }
}

- (void)addVideoPreviewLayerWithRect:(CGRect)previewRect{

    if (!self.previewLayer) {
        AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc]initWithSession:_session];
        previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;

        self.previewLayer = previewLayer;

        [self.preview.layer addSublayer:self.previewLayer];

    }

    self.previewLayer.frame = previewRect;
}

- (void)addvideoInputBackCamera:(BOOL)back{

    NSArray *devices = [AVCaptureDevice devices];

    AVCaptureDevice *frontCamera;
    AVCaptureDevice *backCamera;
    //获取 前、后 摄像头
    for (AVCaptureDevice *device in devices) {

        if ([device hasMediaType:AVMediaTypeVideo]) {

            if ([device position] == AVCaptureDevicePositionBack) {

                backCamera = device;

            }else if([device position] == AVCaptureDevicePositionFront){

                frontCamera = device;

            }
        }
    }

    NSError *error = nil;


    if(back){
        AVCaptureDeviceInput *backCameraDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:backCamera error:&error];
        if (!error) {

            if ([_session canAddInput:backCameraDeviceInput]) {

                [_session addInput:backCameraDeviceInput];
                 self.deviceInput = backCameraDeviceInput;

            }else{
                NSLog(@"出错啦");
            }
        }

    }else{

        AVCaptureDeviceInput *frontCameraDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:frontCamera error:&error];
        if (!error) {

            if ([_session canAddInput:frontCameraDeviceInput]) {

                [_session addInput:frontCameraDeviceInput];
                 self.deviceInput = frontCameraDeviceInput;

            }else{
                NSLog(@"出错啦");
            }
        }
    }


}

- (void)addVideoFlashlightWithFlashModel:(AVCaptureFlashMode )flashModel{

    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    [device lockForConfiguration:nil];

    if ([device hasFlash]) {
        device.flashMode = self.flashMode;
    }

    [device unlockForConfiguration];
}

- (void)addStillImageOutput{

    if (!self.stillImageOutput) {

        AVCaptureStillImageOutput *stillImageOutput = [[AVCaptureStillImageOutput alloc]init];
        NSDictionary *outPutSettingDict = [[NSDictionary alloc]initWithObjectsAndKeys:AVVideoCodecJPEG,AVVideoCodecKey, nil];
        stillImageOutput.outputSettings = outPutSettingDict;

        [_session addOutput:stillImageOutput];

        self.stillImageOutput = stillImageOutput;
    }


}

- (AVCaptureConnection *)findCaptureConnection{


    AVCaptureConnection *videoConnection;

    for (AVCaptureConnection *connection in _stillImageOutput.connections ) {
        for (AVCaptureInputPort *port in connection.inputPorts) {

            if ([[port mediaType] isEqual:AVMediaTypeVideo]) {

                videoConnection = connection;

                return videoConnection;
            }
        }
    }

    return nil;

}