概述：UIPinchGestureRecognizer捏合手勢(shì)歹苦，繼承于UIGestureRecognizer類壹无，相對(duì)于UIGestureRecognizer多了兩個(gè)屬性值萨螺。
/*獲取縮放（捏合）的大小*/
@property (nonatomic) CGFloat scale;
/*獲取縮放（捏合）的速度*/
@property (nonatomic,readonly) CGFloat velocity;
案例：圖片的放大縮小
UIPinchGestureRecognizer *pinchGestureRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchGestureDetected:)];
[pinchGestureRecognizer setDelegate:self];
/*加載到要縮放的圖片*/
[self.image_view addGestureRecognizer:pinchGestureRecognizer];
- (void)pinchGestureDetected:(UIPinchGestureRecognizer *)recognizer{
/*獲取狀態(tài)*/
UIGestureRecognizerState state = [recognizer state];
if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged){
/*獲取捏合大小比例*/
CGFloat scale = [recognizer scale];
/*獲取捏合的速度*/
CGFloat velocity = [recognizer velocity];
NSLog(@"velocity %f",velocity);
[recognizer.view setTransform:CGAffineTransformScale(recognizer.view.transform, scale, scale)];
[recognizer setScale:1.0];
if (self.image_view.frame.size.width <= self.view.bounds.size.width) {
self.image_view.frame = self.view.bounds;
}
}
}
注：了解UIGestureRecognizer類請(qǐng)?zhí)D(zhuǎn)http://www.reibang.com/p/e206dc86f89a
