如何使用或不使用ScrollView使ImageView可缩放。

我的IB有一个UImageView ，并在该UImageView上添加了一个地图图像。 我想让那个图像捏缩放。

这是我的代码：

 - (void)viewDidLoad { [super viewDidLoad]; self.title = @"Map"; self.mapImageView.contentMode = UIViewContentModeScaleAspectFit; [self.mapScrollView addSubview:self.mapImageView]; [self.mapScrollView setContentSize:CGSizeMake(self.mapImageView.frame.size.width, self.mapImageView.frame.size.height)]; [self.mapScrollView setMinimumZoomScale:1.0]; [self.mapScrollView setMaximumZoomScale:4.0]; } - (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView { return self.mapImageView; } 

但这没有用，我可以看到UIScrollView即将发布，但我的图像没有任何反应。
提前致谢。

Answer 1

在ViewController.h文件中添加UIScrollViewDelegate

然后将以下代码添加到ViewController.m文件中

如果您使用此代码，则无需添加UIPinchGestureRecognizer

  - (void)scrollViewDidZoom:(UIScrollView *)scrollView { UIView* zoomView = [scrollView.delegate viewForZoomingInScrollView:scrollView]; CGRect zoomViewFrame = zoomView.frame; if(zoomViewFrame.size.width < scrollView.bounds.size.width) { zoomViewFrame.origin.x = (scrollView.bounds.size.width - zoomViewFrame.size.width) / 2.0; } else { zoomViewFrame.origin.x = 0.0; } if(zoomViewFrame.size.height < scrollView.bounds.size.height) { zoomViewFrame.origin.y = (scrollView.bounds.size.height - zoomViewFrame.size.height) / 2.0; } else { zoomViewFrame.origin.y = 0.0; } zoomView.frame = zoomViewFrame; } 

更改viewDidLoad如下

 - (void)viewDidLoad { [super viewDidLoad]; self.mapScrollView.delegate = self; self.mapScrollView.minimumZoomScale = 1.0; self.mapScrollView.maximumZoomScale = 4.0; UIImage * myImage= [UIImage imageNamed:@"Background.png"]; //add your image here [self.mapImageView setImage:myImage]; [self.mapImageView sizeToFit]; self.mapScrollView.contentSize = myImage.size; } 

指定imageView以放大此处

 - (UIView*)viewForZoomingInScrollView:(UIScrollView *)scrollView { return self.mapImageView; } 

要避免UIScrollView在zoomimg上的奇怪行为，请使用此方法

 - (void)view:(UIView*)view setCenter:(CGPoint)centerPoint { CGRect viewFrame = view.frame; CGPoint contentOffset = self.mapScrollView.contentOffset; CGFloat x = centerPoint.x - viewFrame .size.width / 2.0; CGFloat y = centerPoint.y - viewFrame .size.height / 2.0; if(x < 0) { contentOffset.x = -x; viewFrame .origin.x = 0.0; } else { viewFrame .origin.x = x; } if(y < 0) { contentOffset.y = -y; viewFrame .origin.y = 0.0; } else { viewFrame .origin.y = y; } view.frame = viewFrame ; self.mapScrollView.contentOffset = contentOffset; } 

然后在viewDidAppear上调用上面的方法

 - (void)viewDidAppear:(BOOL)animated { [super viewDidAppear:animated]; CGPoint centerPoint = CGPointMake(CGRectGetMidX(self.mapScrollView.bounds), CGRectGetMidY(self.mapScrollView.bounds)); [self view:self.mapImageView setCenter:centerPoint]; } 

如果您需要更多说明，请查看此链接 。 我从那个链接学到了这个技巧。

Answer 2

试试这个

  //At ViewDidLoad (OR whare you create your mapImageView) UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scale:)]; [pinchRecognizer setDelegate:self]; [mapImageView addGestureRecognizer:pinchRecognizer]; mapImageView.userInteractionEnabled=YES; -(void)scale:(id)sender { [YourView bringSubviewToFront:[(UIPinchGestureRecognizer*)sender view]]; if([(UIPinchGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) { lastScale = 1.0; //global float variable. return; } CGFloat scale = 1.0 - (lastScale - [(UIPinchGestureRecognizer*)sender scale]); CGAffineTransform currentTransform = [(UIPinchGestureRecognizer*)sender view].transform; CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, scale, scale); [[(UIPinchGestureRecognizer*)sender view] setTransform:newTransform]; } 

Answer 3

如果没有scrollView ，请将此代码scrollView添加到您的class级：

 -(void) addGesturesTo : (UIImageView *) imageView{ // Register for double-finger dragging to pan the camera. UIPinchGestureRecognizer* pinchGestureReconizer = [[UIPinchGestureRecognizer alloc] initWithTarget: self action: @selector(handlePich:)]; [imageView addGestureRecognizer:pinchGestureReconizer]; } - (void) handlePich: (UIPinchGestureRecognizer *) pinchGestureRecognizer{ CGFloat scale = pinchGestureRecognizer.scale; [[pinchGestureRecognizer view] setTransform:CGAffineTransformScale([pinchGestureRecognizer view].transform, scale, scale)]; pinchGestureRecognizer.scale = 1.0; } 

现在用addGesturesTo调用addGesturesTo 。 如：

 [self addGesturesTo:imageView]; 

使用ScrollView执行此操作：请按照下列步骤操作：

• 将scrollView set delegate添加到self
• 在scrolView添加scrolView
• 实现- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView; 在你的类中并返回imageView