@ Anil的回答是一个很好的开始，但它并没有为我工作。我希望能够让用户继续选择焦点，而不是仅仅选择一次（这是他的解决方案所做的）。感谢@Anil指引我朝着正确的方向发展。
有我的解决方案存在一些差异。
- 我希望能够重复使用焦点正方形和动画，而不是只重复一次。
- 我想要的动画消失后，它完成（的东西，我不能让@ Anil的解决方案做。
- 而不是使用
initWithFrame:的，我实现我自己的initWithTouchPoint:。
- 我有专门动画的方法聚焦动作。
- 我也有一个方法，用于更新所述帧的位置。
- 帧的大小是内
CameraFocusSquare，这意味着它更容易找到，并根据需要更新的大小。
CameraFocusSquare.h
@import UIKit;
@interface CameraFocusSquare : UIView
- (instancetype)initWithTouchPoint:(CGPoint)touchPoint;
- (void)updatePoint:(CGPoint)touchPoint;
- (void)animateFocusingAction;
@end
CameraFocusSquare.m
#import "CameraFocusSquare.h"
@implementation CameraFocusSquare {
CABasicAnimation *_selectionBlink;
}
/**
This is the init method for the square. It sets the frame for the view and sets border parameters. It also creates the blink animation.
*/
- (instancetype)initWithTouchPoint:(CGPoint)touchPoint {
self = [self init];
if (self) {
[self updatePoint:touchPoint];
self.backgroundColor = [UIColor clearColor];
self.layer.borderWidth = 2.0f;
self.layer.borderColor = [UIColor orangeColor].CGColor;
// create the blink animation
_selectionBlink = [CABasicAnimation
animationWithKeyPath:@"borderColor"];
_selectionBlink.toValue = (id)[UIColor whiteColor].CGColor;
_selectionBlink.repeatCount = 3; // number of blinks
_selectionBlink.duration = 0.4; // this is duration per blink
_selectionBlink.delegate = self;
}
return self;
}
/**
Updates the location of the view based on the incoming touchPoint.
*/
- (void)updatePoint:(CGPoint)touchPoint {
CGFloat squareWidth = 50;
CGRect frame = CGRectMake(touchPoint.x - squareWidth/2, touchPoint.y - squareWidth/2, squareWidth, squareWidth);
self.frame = frame;
}
/**
This unhides the view and initiates the animation by adding it to the layer.
*/
- (void)animateFocusingAction {
// make the view visible
self.alpha = 1.0f;
self.hidden = NO;
// initiate the animation
[self.layer addAnimation:_selectionBlink forKey:@"selectionAnimation"];
}
/**
Hides the view after the animation stops. Since the animation is automatically removed, we don't need to do anything else here.
*/
- (void)animationDidStop:(CAAnimation *)animation finished:(BOOL)flag {
// hide the view
self.alpha = 0.0f;
self.hidden = YES;
}
@end
我开始这一切对视图的顶部。这让我有更大的灵活性，并将我的UI代码与我的控制器代码分开（认为MVC）。
PreviewView.h
@import UIKit;
@interface PreviewView : UIView
- (IBAction)tapToFocus:(UITapGestureRecognizer *)gestureRecognizer;
@end
PreviewView.m
#import "PreviewView.h"
#import "CameraFocusSquare.h"
@implementation PreviewView {
CameraFocusSquare *_focusSquare;
}
- (IBAction)tapToFocus:(UITapGestureRecognizer *)gestureRecognizer {
CGPoint touchPoint = [gestureRecognizer locationOfTouch:0 inView:self];
if (!_focusSquare) {
_focusSquare = [[CameraFocusSquare alloc] initWithTouchPoint:touchPoint];
[self addSubview:_focusSquare];
[_focusSquare setNeedsDisplay];
}
else {
[_focusSquare updatePoint:touchPoint];
}
[_focusSquare animateFocusingAction];
}
@end
最后，在我的UIViewController子类中，我有我的UITapGestureRecognizer创建并连接到视图。我也在这里实现了我的tap-to-focus代码。
CameraViewController.m
- (void)viewDidLoad {
// do other initialization stuff here
// create the tap-to-focus gesture
UITapGestureRecognizer *tapToFocusRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapToFocus:)];
tapToFocusRecognizer.numberOfTapsRequired = 1;
tapToFocusRecognizer.numberOfTouchesRequired = 1;
[self.previewView addGestureRecognizer:tapToFocusRecognizer];
}
- (IBAction)tapToFocus:(UITapGestureRecognizer *)tapGestureRecognizer {
if (!_captureDevice) {
return;
}
if (![_captureDevice isFocusPointOfInterestSupported]) {
return;
}
if (![_captureDevice isFocusModeSupported:AVCaptureFocusModeAutoFocus]) {
return;
}
[self.previewView tapToFocus:tapGestureRecognizer];
NSError *error;
[_captureDevice lockForConfiguration:&error];
if (error) {
NSLog(@"Error trying to lock configuration of camera. %@", [error localizedDescription]);
return;
}
CGPoint touchPoint = [tapGestureRecognizer locationOfTouch:0 inView:self.cameraView];
// range of touch point is from (0,0) to (1,1)
CGFloat touchX = touchPoint.x/self.previewView.frame.size.width;
CGFloat touchY = touchPoint.y/self.previewView.frame.size.height;
_captureDevice.focusMode = AVCaptureFocusModeAutoFocus;
if ([_captureDevice isExposureModeSupported:AVCaptureExposureModeAutoExpose]) {
_captureDevice.exposureMode = AVCaptureExposureModeAutoExpose;
}
_captureDevice.focusPointOfInterest = CGPointMake(touchX, touchY);
if ([_captureDevice isExposurePointOfInterestSupported]) {
_captureDevice.exposurePointOfInterest = CGPointMake(touchX, touchY);
}
[_captureDevice unlockForConfiguration];
}
希望这有助于人，使他们能够移动到更重要的代码！
无关你的问题，但是，你应该使用'如果（ CaptureDeviceClass！=无）' – 2013-03-16 14:20:52
谢谢你的提示。我现在还没有真正关心和了解这些差异，所以我查了一下。由于我引用一个类的事实，你是绝对正确的。 – Alexander 2013-03-16 15:22:57
@亚历山大，我面临与你一样的问题。你解决了这个问题吗？ – ttotto 2013-04-05 09:27:12