iOS使用视听媒体框架AVFoundation实现照片拍摄

#import "HWPhotoVC.h"
#import 
 
@interface HWPhotoVC ()
 
@property (nonatomic, strong) AVCaptureSession *captureSession;//负责输入和输出设备之间的数据传递
@property (nonatomic, strong) AVCaptureDeviceInput *captureDeviceInput;//负责从AVCaptureDevice获得输入数据
@property (nonatomic, strong) AVCaptureStillImageOutput *captureStillImageOutput;//照片输出流
@property (nonatomic, strong) AVCaptureVideoPreviewLayer *captureVideoPreviewLayer;//相机拍摄预览图层
@property (nonatomic, weak) UIView *containerView;//内容视图
@property (nonatomic, weak) UIImageView *focusCursor;//聚焦按钮
@property (nonatomic, weak) UIImageView *imgView;//拍摄照片
 
@end
 
@implementation HWPhotoVC
 
- (void)viewDidLoad {
 [super viewDidLoad];
 
 self.navigationItem.title = @"拍照";
 self.view.backgroundColor = [UIColor whiteColor];
 
 //创建控件
 [self creatControl];
}
 
- (void)viewWillAppear:(BOOL)animated
{
 [super viewWillAppear:animated];
 
 //初始化信息
 [self initPhotoInfo];
}
 
- (void)viewDidAppear:(BOOL)animated
{
 [super viewDidAppear:animated];
 
 [self.captureSession startRunning];
}
 
- (void)viewDidDisappear:(BOOL)animated
{
 [super viewDidDisappear:animated];
 
 [self.captureSession stopRunning];
}
 
- (void)creatControl
{
 CGFloat btnW = 150.f;
 CGFloat btnH = 40.f;
 CGFloat marginY = 20.f;
 CGFloat w = [UIScreen mainScreen].bounds.size.width;
 CGFloat h = [UIScreen mainScreen].bounds.size.height;
 
 //内容视图
 CGFloat cOntainerViewH= h - 64 - btnH - marginY * 3;
 UIView *cOntainerView= [[UIView alloc] initWithFrame:CGRectMake(10, 64 + marginY, w - 20, containerViewH)];
 containerView.backgroundColor = [UIColor whiteColor];
 containerView.layer.borderWidth = 1.f;
 containerView.layer.borderColor = [[UIColor grayColor] CGColor];
 [self.view addSubview:containerView];
 _cOntainerView= containerView;
 
 //摄像头切换按钮
 CGFloat cameraSwitchBtnW = 50.f;
 CGFloat cameraSwitchBtnMargin = 10.f;
 UIButton *cameraSwitchBtn = [[UIButton alloc] initWithFrame:CGRectMake(containerView.bounds.size.width - cameraSwitchBtnW - cameraSwitchBtnMargin, 64 + marginY + cameraSwitchBtnMargin, cameraSwitchBtnW, cameraSwitchBtnW)];
 [cameraSwitchBtn setImage:[UIImage imageNamed:@"camera_switch"] forState:UIControlStateNormal];
 [cameraSwitchBtn addTarget:self action:@selector(cameraSwitchBtnOnClick) forControlEvents:UIControlEventTouchUpInside];
 [self.view addSubview:cameraSwitchBtn];
 
 //聚焦图片
 UIImageView *focusCursor = [[UIImageView alloc] initWithFrame:CGRectMake(50, 50, 75, 75)];
 focusCursor.alpha = 0;
 focusCursor.image = [UIImage imageNamed:@"camera_focus_red"];
 [containerView addSubview:focusCursor];
 _focusCursor = focusCursor;
 
 //拍摄照片容器
 UIImageView *imgView = [[UIImageView alloc] initWithFrame:containerView.frame];
 imgView.hidden = YES;
 imgView.layer.borderWidth = 1.f;
 imgView.layer.borderColor = [[UIColor grayColor] CGColor];
 imgView.cOntentMode= UIViewContentModeScaleAspectFill;
 imgView.clipsToBounds = YES;
 [self.view addSubview:imgView];
 _imgView = imgView;
 
 //按钮
 NSArray *titleArray = @[@"拍摄照片", @"重新拍摄"];
 CGFloat btnY = CGRectGetMaxY(containerView.frame) + marginY;
 CGFloat margin = (w - btnW * titleArray.count) / (titleArray.count + 1);
 for (int i = 0; i