Cocoa touch 使用双指夹点放大collectionView Xcode

我有一个在scrollView中包含collectionView的应用程序。我使用下面的代码来放大和平移

-(void) viewDidLoad {
    [super viewDidLoad];

    twoFingerPinchA = [[UIPinchGestureRecognizer alloc]
                                                initWithTarget:self
                                                action:@selector(twoFingerPinch:)]
    ;
    [self.view addGestureRecognizer:(twoFingerPinchA)];
}

-(void)twoFingerPinch:(UIPinchGestureRecognizer *)recognizer{

  CGAffineTransform transform = CGAffineTransformMakeScale(twoFingerPinchA.scale, twoFingerPinchA.scale);

    if (twoFingerPinchA.scale < 1) {
        twoFingerPinchA.scale = 1;
    }

    if (twoFingerPinchA.scale >2) {
        twoFingerPinchA.scale = 2;
    }
    self.scrolling.transform = transform;

}

所以我想出来了

首先我使用了这个代码

-(void) viewWillAppear:(BOOL)animated{
    NSString *pinchString = @"1.0";
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    [defaults setObject:pinchString forKey:@"pinchValue"];
  }

//这是为了确保pinchValue键在首次安装应用程序时具有值

然后我把这个

switch ([twoFingerPinchA state]) {
        case UIGestureRecognizerStatePossible:
        {
        }
            break;
        case UIGestureRecognizerStateBegan:
        {
            NSString *inPinch = [[NSUserDefaults standardUserDefaults] objectForKey:@"pinchValue"];
            float Pinch = [inPinch floatValue];
           twoFingerPinchA.scale = Pinch;
         }
            break;
        case UIGestureRecognizerStateChanged:
        {
         }
            break;
        case UIGestureRecognizerStateEnded:
        {
            NSString *pinchString = [NSString  stringWithFormat:@"%f",twoFingerPinchA.scale];
            NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
            [defaults setObject:pinchString forKey:@"pinchValue"];
          }
            break;
        case UIGestureRecognizerStateCancelled:
        {
        }
            break;
        case UIGestureRecognizerStateFailed:
        {
        }
            break;
    }

在我的 -（void）twoFingerPinch：（UIPinchGestureRecognitor*）识别器{}

当挤压结束时，它将twoFingerPinchA.scale的值存储在usersDefaults中

及

再次开始时，将twoFingerPinchA.scales设置为该存储值。在此基础上，根据该值进行上下/进出调整

效果很好

switch ([twoFingerPinchA state]) {
        case UIGestureRecognizerStatePossible:
        {
        }
            break;
        case UIGestureRecognizerStateBegan:
        {
            NSString *inPinch = [[NSUserDefaults standardUserDefaults] objectForKey:@"pinchValue"];
            float Pinch = [inPinch floatValue];
           twoFingerPinchA.scale = Pinch;
         }
            break;
        case UIGestureRecognizerStateChanged:
        {
         }
            break;
        case UIGestureRecognizerStateEnded:
        {
            NSString *pinchString = [NSString  stringWithFormat:@"%f",twoFingerPinchA.scale];
            NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
            [defaults setObject:pinchString forKey:@"pinchValue"];
          }
            break;
        case UIGestureRecognizerStateCancelled:
        {
        }
            break;
        case UIGestureRecognizerStateFailed:
        {
        }
            break;
    }