我想知道是否可以在iPhone应用程序中收到有关自动对焦的通知?
I.E,是否存在自动对焦开始,结束,如果成功或失败时通知的方式......?
如果是,这个通知名称是什么?
答案 0 :(得分:44)
我找到了自动对焦开始/结束时我的案例的解决方案。它只是处理KVO(键值观察)。
在我的UIViewController中:
// callback
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
if( [keyPath isEqualToString:@"adjustingFocus"] ){
BOOL adjustingFocus = [ [change objectForKey:NSKeyValueChangeNewKey] isEqualToNumber:[NSNumber numberWithInt:1] ];
NSLog(@"Is adjusting focus? %@", adjustingFocus ? @"YES" : @"NO" );
NSLog(@"Change dictionary: %@", change);
}
}
// register observer
- (void)viewWillAppear:(BOOL)animated{
AVCaptureDevice *camDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
int flags = NSKeyValueObservingOptionNew;
[camDevice addObserver:self forKeyPath:@"adjustingFocus" options:flags context:nil];
(...)
}
// unregister observer
- (void)viewWillDisappear:(BOOL)animated{
AVCaptureDevice *camDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
[camDevice removeObserver:self forKeyPath:@"adjustingFocus"];
(...)
}
文档:
答案 1 :(得分:3)
Swift 3
在AVCaptureDevice
实例上设置焦点模式:
do {
try videoCaptureDevice.lockForConfiguration()
videoCaptureDevice.focusMode = .continuousAutoFocus
videoCaptureDevice.unlockForConfiguration()
} catch {}
添加观察者:
videoCaptureDevice.addObserver(self, forKeyPath: "adjustingFocus", options: [.new], context: nil)
覆盖observeValue
:
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
guard let key = keyPath, let changes = change else {
return
}
if key == "adjustingFocus" {
let newValue = changes[.newKey]
print("adjustingFocus \(newValue)")
}
}
答案 2 :(得分:0)
您可以使用现代的Swift键值观察api通过观察AVCaptureDeviceInput.device.isAdjustingFocus
属性来获取焦点开始和结束时的回调。在下面的示例中,AVCaptureDeviceInput
的实例称为captureDeviceInput
。
示例:
self.focusObservation = observe(\.captureDeviceInput.device.isAdjustingFocus, options: .new) { _, change in
guard let isAdjustingFocus = change.newValue else { return }
print("isAdjustingFocus = \(isAdjustingFocus)")
}