Question

所以我试图创建一个LED频闪灯，我已经设法为灯打开/关闭开关。这是我的代码：

@implementation ViewController
- (void) setTorchOn:(BOOL)isOn
{
AVCaptureDevice* device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
[device lockForConfiguration:nil];
[device setTorchMode:isOn ? AVCaptureTorchModeOn : AVCaptureTorchModeOff];
[device unlockForConfiguration];

}

-(IBAction)changedSate:(id)sender {
UISwitch *switchValue = (UISwitch*)sender;

[self setTorchOn:[switchValue isOn]];

我想知道是否有人可以帮我解决这个问题。

Answer 1

只需做一个循环，持续打开和关闭火炬。循环的类型取决于您希望如何实现它。

Answer 2

我认为你应该使用NSTimer课来反复切换火炬。还有其他方法，但只需使用sleep（）调用不循环。

// Have an NSTimer* timer and BOOL torchOn and volatile BOOL stopStrobe property in your class...

- (void) startFlashing{
self.timer = [[NSTimer alloc] initWithFireDate:[NSDate timeInvervalSinceNow: 0] interval:0.1 target:self selector:@selector(toggleTorch) userInfo:nil repeats:YES];
}

- (void) toggleTorch{
   if (stopStrobe){
      [self.timer invalidate];
   }
   torchOn = !torchOn
   [self setTorchOn:torchOn];
   }

// Set stopStrobe to YES elsewhere in your program when you want it to stop.

可能是您正在寻找的。

更新：我知道这不是你最初提出的问题，但我知道通常最好通过示例来学习，所以这里是使用这个（未经测试）的完整示例：

@interface ViewController()
@property(nonatomic) BOOL torchOn;
@property(atomic) BOOL stopStrobe;
@end

@implementation ViewController
- (id) init{
self = [super init];
if (self){
self.torchOn = NO;
self.stopStrobe = NO;
}
}

- (void) setTorchOn:(BOOL)isOn
{
AVCaptureDevice* device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
[device lockForConfiguration:nil];
[device setTorchMode:isOn ? AVCaptureTorchModeOn : AVCaptureTorchModeOff];
[device unlockForConfiguration];
}

- (void) toggleTorch{
if (stopStrobe){
[self.timer invalidate];
}
self.torchOn = !self.torchOn
[self setTorchOn:self.torchOn];
}

- (void) startFlashing{
self.timer = [[NSTimer alloc] initWithFireDate:[NSDate timeInvervalSinceNow: 0] interval:0.1 target:self selector:@selector(toggleTorch) userInfo:nil repeats:YES];
}

-(IBAction)changedSate:(id)sender {
UISwitch *switchValue = (UISwitch*)sender;
if ([switchValue isOn]{
self.stopStrobe = NO;
[self startFlashing];
}
else{
[self.stopStrobe = YES];
}
}

无论何时打开开关都会开始闪烁，一旦关闭开关就会停止闪烁。

实现频闪功能

2 个答案: