我使用以下代码使用UISwipeGestureRecognizer左右滑动，以类似于 iPhoto 的方式在我的应用程序中显示照片。
CATransition *animation = [CATransition animation];
[animation setDuration:0.5];
[animation setType:kCATransitionPush];
[animation setSubtype:kCATransitionFromRight];
[animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
[[self.imageHolder layer] addAnimation:animation forKey:@"SwitchToView"];
这会将下一张图像滑入并滑出旧图像，如下图所示：
图一：
过渡：
图二：
当我突然意识到我应该使用UIPanGestureRecognizer时，我想知道如何让它像 iPhoto 一样。
我需要像 iPhoto 那样用手指“控制”动画，即允许我开始拖动到下一张图像，然后反转拖动方向。此外，以与 iPhoto 类似的方式，如果在显示的下一张图像比第一张图像更多时松开手指，我希望下一张图像滑入（这在上面的过渡图片中没有发生，如果我释放我的手指此时在 iPhoto 中它会滑回第一张图像。
我以前从未使用过UIPanGestureRecognizer，所以如果有人可以帮助我，那就太好了。
编辑：
使用Levi提供的代码，我创建了一个适用于 3 个示例图像的解决方案。对于任何有兴趣使用UIPanGestureRecognizer的人，代码是：
界面：
#import <UIKit/UIKit.h>
@interface ViewController : UIViewController <UIGestureRecognizerDelegate>
{
int imageIndex;
}
@property (nonatomic, strong) UIImageView* imageView;
@property (nonatomic, strong) UIImageView* leftImageView;
@property (nonatomic, strong) UIImageView* rightImageView;
@end
执行：
#import "ViewController.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
self->imageIndex = 0;
float xFactor;
UIInterfaceOrientation currentOrientation = self.interfaceOrientation;
if(UIInterfaceOrientationIsLandscape(currentOrientation)){
xFactor = 256;
}
else{
xFactor = 0;
}
self.imageView = [[UIImageView alloc] initWithFrame:self.view.frame];
self.imageView.contentMode = UIViewContentModeScaleAspectFit;
self.imageView.image = [UIImage imageNamed:@"69B4356B-1CB2-4A2F-867E-9C086251DF11-12668-0000036A534E9B6D"];
self.imageView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
CGRect leftFrame = self.view.frame;
leftFrame.origin.x -= leftFrame.size.width+xFactor;
self.leftImageView = [[UIImageView alloc] initWithFrame:leftFrame];
self.leftImageView.contentMode = UIViewContentModeScaleAspectFit;
self.leftImageView.image = [UIImage imageNamed:@"42517D93-F8BF-42E7-BB44-53B099A482AA-12668-0000036A49BCECAA"];
self.leftImageView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
CGRect rightFrame = self.view.frame;
rightFrame.origin.x += rightFrame.size.width+xFactor;
self.rightImageView = [[UIImageView alloc] initWithFrame:rightFrame];
self.rightImageView.contentMode = UIViewContentModeScaleAspectFit;
self.rightImageView.image = [UIImage imageNamed:@"C6AC2508-243B-464B-A71F-96DD7F18673D-12668-00000369F3AFD3FC"];
self.rightImageView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
[self.view addSubview:self.imageView];
[self.view addSubview:self.leftImageView];
[self.view addSubview:self.rightImageView];
UIPanGestureRecognizer *recognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];
[self.view addGestureRecognizer:recognizer];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
}
- (void)handlePan:(UIPanGestureRecognizer *)recognizer {
if (recognizer.state == UIGestureRecognizerStateEnded) {
CGRect leftFrame = self.leftImageView.frame;
CGRect currentFrame = self.imageView.frame;
CGRect rightFrame = self.rightImageView.frame;
float duration = 0.0;
float factor;
UIInterfaceOrientation currentOrientation = self.interfaceOrientation;
if(UIInterfaceOrientationIsPortrait(currentOrientation)){
factor = 768;
}
else{
factor = 1024;
}
if (self.imageView.center.x < 0) { // Present the right image
duration = 0.3 * ABS(self.rightImageView.frame.origin.x / factor);
leftFrame.origin.x = -2 * factor;
currentFrame.origin.x = -1 * factor;
rightFrame.origin.x = 0;
self->imageIndex = 1;
} else if (self.imageView.center.x > factor) { // Present the left image
duration = 0.3 * ABS(self.leftImageView.frame.origin.x / factor);
leftFrame.origin.x = 0;
currentFrame.origin.x = factor;
rightFrame.origin.x = 2 * factor;
self->imageIndex = -1;
} else { // leave the middle image
duration = 0.3 * ABS(self.imageView.frame.origin.x / factor);
leftFrame.origin.x = -1 * factor;
currentFrame.origin.x = 0;
rightFrame.origin.x = factor;
self->imageIndex = 0;
}
[UIView animateWithDuration:duration
delay:0
options:UIViewAnimationOptionCurveEaseInOut
animations:^{
self.leftImageView.frame = leftFrame;
self.imageView.frame = currentFrame;
self.rightImageView.frame = rightFrame;
} completion:^(BOOL finished) {
}];
} else {
CGPoint translation = [recognizer translationInView:recognizer.view];
CGPoint leftCenter = self.leftImageView.center;
CGPoint currentCenter = self.imageView.center;
CGPoint rightCenter = self.rightImageView.center;
leftCenter.x += translation.x;
currentCenter.x += translation.x;
rightCenter.x += translation.x;
self.leftImageView.center = leftCenter;
self.imageView.center = currentCenter;
self.rightImageView.center = rightCenter;
[recognizer setTranslation:CGPointMake(0, 0) inView:self.imageView];
}
}
- (void)willAnimateRotationToInterfaceOrientation:
(UIInterfaceOrientation)toInterfaceOrientation
duration:(NSTimeInterval)duration
{
CGPoint leftCenter = self.leftImageView.center;
CGPoint currentCenter = self.imageView.center;
CGPoint rightCenter = self.rightImageView.center;
if(UIInterfaceOrientationIsPortrait(toInterfaceOrientation)){
leftCenter.x = 384+(((-self->imageIndex)-1)*768);
currentCenter.x = 384+((-self->imageIndex)*768);
rightCenter.x = 384+(((-self->imageIndex)+1)*768);
}
else{
leftCenter.x = 512+(((-self->imageIndex)-1)*1024);
currentCenter.x = 512+((-self->imageIndex)*1024);
rightCenter.x = 512+(((-self->imageIndex)+1)*1024);
}
self.leftImageView.center = leftCenter;
self.imageView.center = currentCenter;
self.rightImageView.center = rightCenter;
}
@end