IOS-手电筒照明

打开手电筒照明的思路：初始化相机设备 -> 点击按钮 -> 改变照明状态 -> 根据状态打开或关闭手电筒

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

@interface ViewController ()

@property (nonatomic, strong) AVCaptureDevice *device;//捕获设备

@end

@implementation ViewController
{
    BOOL device_open;//判断照明状态
    UIButton *scanBtn;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
  
    //创建按钮
    [self creatControl];
}

- (void)creatControl {

    //初始化相机设备
    self.device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

    //照明按钮
    scanBtn = [UIButton buttonWithType:UIButtonTypeSystem];
    scanBtn.frame = CGRectMake(100, 100, 100, 44);
    [scanBtn setTitle:@"打开照明" forState:UIControlStateNormal];
    [scanBtn addTarget:self action:@selector(scanBtnOnClick) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:scanBtn];
    
}

-(void)scanBtnOnClick {  
    
    NSLog(@"%@",device_open?@"YES":@"NO");
    
    //改变状态
    device_open = !device_open;
    
    //判断设备是否有闪关灯
    if (![self.device hasTorch]) {
        UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"提示"
                                                                       message:@"当前设备没有闪关灯，无法开启照明功能"
                                                                preferredStyle:UIAlertControllerStyleAlert];
        UIAlertAction *sureAction = [UIAlertAction actionWithTitle:@"确认"
                                                             style:UIAlertActionStyleDefault
                                                           handler:^(UIAlertAction * _Nonnull action) {
        }];
        UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消"
                                                               style:UIAlertActionStyleCancel
                                                             handler:^(UIAlertAction * _Nonnull action) {
        }];
        [alert addAction:sureAction];
        [alert addAction:cancelAction];
        
        [self presentViewController:alert animated:YES completion:nil];
    }
    
    [self.device lockForConfiguration:nil];
    
    //根据状态，打开或关闭照明
    if (device_open) {
        [self.device setTorchMode:AVCaptureTorchModeOn];
        [scanBtn setTitle:@"关闭照明" forState:UIControlStateNormal];
    }
    else {
        [self.device setTorchMode:AVCaptureTorchModeOff];
        [scanBtn setTitle:@"打开照明" forState:UIControlStateNormal];
    }
}

@end