#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>

@interface ViewController ()
@property (nonatomic, strong) AVCaptureDevice *device;
@property (nonatomic,assign) BOOL lightOn;
@end

@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
    
    _device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    //hasTorch :返回YES表名手机上有手电筒
    if (![_device hasTorch]) {
        NSLog(@"手电筒坏了");
        return;
    }
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    
    _lightOn = !_lightOn;
    
    //根据ligthOn状态判断打开还是关闭
    if (_lightOn) {
        
        // 请求独占访问硬件设备
        [_device lockForConfiguration:nil];
        // 开启手电筒
        [_device setTorchMode:AVCaptureTorchModeOn];
        // 解除独占访问硬件设备
        [_device unlockForConfiguration];
        
    }else{
        //关闭手电筒
        [_device lockForConfiguration:nil];
        
        [_device setTorchMode:AVCaptureTorchModeOff];
        
        [_device unlockForConfiguration];
        
    }
    
}