ios开发——手势识别（Pinch）

#import "ViewController.h"

@interface ViewController ()
{
    //缩放因子
    CGFloat currentScale;
}

@property (strong, nonatomic) UIImage *imageTrashFull;
@property (strong, nonatomic) UIImageView *imageView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    //界面初始化
    CGRect screen = [[UIScreen mainScreen] bounds];
    CGFloat imageViewWidth = 128;
    CGFloat imageViewHeight = 128;
    CGFloat imageViewTopView = 300;
    CGRect frame = CGRectMake((screen.size.width - imageViewWidth)/2 , imageViewTopView, imageViewWidth, imageViewHeight);
    self.imageView = [[UIImageView alloc] initWithFrame:frame];
    [self.view addSubview:self.imageView];

    //创建图片对象
    self.imageTrashFull = [UIImage imageNamed:@"Blend Trash Full"];
    self.imageView.image = self.imageTrashFull;
    
    //创建Pinch手势识别器
    UIPinchGestureRecognizer *recognizer =[[UIPinchGestureRecognizer alloc]
                                            initWithTarget:self
                                            action:@selector(foundPinch:)];
    //Pinch手势识别器关联到imageView
    [self.imageView addGestureRecognizer:recognizer];
    //设置imageView开启用户事件
    self.imageView.userInteractionEnabled = YES;
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
}

- (void)foundPinch:(UIPinchGestureRecognizer*)sender {

    NSLog(@"缩放因子 = %f",sender.scale);
    
    if (sender.state == UIGestureRecognizerStateEnded){
        currentScale = sender.scale;
    } else if (sender.state == UIGestureRecognizerStateBegan && currentScale != 0.0f){
        sender.scale = currentScale;
    }
    self.imageView.transform = CGAffineTransformMakeScale(sender.scale, sender.scale);
}

@end