Question

我希望用滑块选项调暗手电筒的LED。我知道Apple支持iOS 6但是，我不确定要使用什么代码。这是我目前在.m文件中的代码。

-(IBAction)torchOn:(id)sender;
{
    onButton.hidden = YES;
    offButton.hidden = NO;

    onView.hidden = NO;
    offView.hidden = YES;


    AVCaptureDevice *flashLight = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    if([flashLight isTorchAvailable] && [flashLight isTorchModeSupported:AVCaptureTorchModeOn])
    {
        BOOL success = [flashLight lockForConfiguration:nil];
        if(success)
        {
            [flashLight setTorchMode:AVCaptureTorchModeOn];
            [flashLight unlockForConfiguration];
        }
    }
}


-(IBAction)torchOff:(id)sender;
{
    onButton.hidden = NO;
    offButton.hidden = YES;

    onView.hidden = YES;
    offView.hidden = NO;

    AVCaptureDevice *flashLight = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    if([flashLight isTorchAvailable] && [flashLight isTorchModeSupported:AVCaptureTorchModeOn])
    {
        BOOL success = [flashLight lockForConfiguration:nil];
        if(success)
        {
            [flashLight setTorchMode:AVCaptureTorchModeOff];
            [flashLight unlockForConfiguration];
        }
    }
}

Answer 1

- (BOOL)setTorchModeOnWithLevel:(float)torchLevel error:(NSError **)outError

你想做什么。但是，从我所看到的情况来看，它只会在一定的时间间隔内更新（~0.2）。

AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
[device lockForConfiguration:nil];
[device setTorchModeOnWithLevel:slider.value error:NULL];
[device unlockForConfiguration];

编辑 - 完整示例：

这是一个UISlider。您需要在滑块上添加IBAction插座或以编程方式添加目标（就像我一样）：

UISlider *slider = [[UISlider alloc] initWithFrame:CGRectMake(20.0f, 20.0f, 280.0f, 40.0f)];
slider.maximumValue = 1.0f;
slider.minimumValue = 0.0f;
[slider setContinuous:YES];
[slider addTarget:self action:@selector(sliderDidChange:) forControlEvents:UIControlEventValueChanged];
[self.view addSubview:slider];

然后，响应滑块更改：

- (void)sliderDidChange:(UISlider *)slider
{
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    [device lockForConfiguration:nil];
    [device setTorchModeOnWithLevel:slider.value error:NULL];
    [device unlockForConfiguration];
}

Answer 2

如果有两个滑块，那是因为滑块设置在m中。文件，您必须删除代码的[self.view addSubview:slider];部分。

在Xcode中为iPhone 5手电筒应用调暗LED

2 个答案: