Question

我是否真的需要在UIScrollView中使用UIPinchGestureRecognizer才能使捏合工作？如果是，我该怎么办？我正在尝试实现flipboard所具有的功能，它基本上放大图像并在放大后具有滚动功能。我该怎么做？

更新

这里有一些我没有调用滚动视图委托的代码

CGRect imgFrame;
imgFrame.size.width = originalImageSize.width;
imgFrame.size.height = originalImageSize.height;
imgFrame.origin.x = imageOriginPoint.x;
imgFrame.origin.y = imageOriginPoint.y;

NSData *data = [request responseData];
UIImage * image = [UIImage imageWithData:data];
imageView = [[UIImageView alloc] initWithImage:image];
[imageView setUserInteractionEnabled:YES];
[imageView setBackgroundColor:[UIColor clearColor]];
[imageView setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight];
[imageView setFrame:CGRectMake(0, 0, imgFrame.size.width, imgFrame.size.height)];

UIScrollView * imgScrollView = [[UIScrollView alloc] initWithFrame:imageView.frame];
imgScrollView.delegate = self;
imgScrollView.showsVerticalScrollIndicator = NO;
imgScrollView.showsHorizontalScrollIndicator = NO;
[imgScrollView setScrollEnabled:YES];
[imgScrollView setClipsToBounds:YES];
[imgScrollView addSubview:imageView];
[imgScrollView setBackgroundColor:[UIColor blueColor]];
[imgScrollView setMaximumZoomScale:1.0];

Answer 1

您需要做的只是在UIImageView内添加UIScrollView（或任何想要缩放的视图）。

将maximumZoomScale上的UIScrollView设置为高于1.0f的任何值。

将自己设置为UIScrollView的代理人，并在viewForZooming委托方法中返回UIImageView。

就是这样。不需要捏手势，没有任何东西。 UIScrollView为您处理缩放缩放。

Answer 2

Swift 2.0 Scrollview步骤中的缩放图像（Swift 2.0）

<强> 1。滚动视图约束

<强> 2。在ScrollView中添加ImageView并设置约束

第3。参加IBOutlets

IBOutlet UIScrollView * bgScrollView;
IBOutlet UIImageView * imageViewOutlet;

<强> 4。 viewDidLoad方法

- (void)viewDidLoad
 {
    [super viewDidLoad];

    float minScale=bgScrollView.frame.size.width / imageViewOutlet.frame.size.width;
    bgScrollView.minimumZoomScale = minScale;
    bgScrollView.maximumZoomScale = 3.0;
    bgScrollView.contentSize = imageViewOutlet.frame.size;
    bgScrollView.delegate = self;
}

<强> 5。滚动查看委派方法

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
    return imageViewOutlet;
}

Answer 3

我很久以前没有使用捏合识别器做了自定义图像查看器。在UIScrollView上只有UIImageView。你传递一个带有图像链接的字符串，它还有一个进度条。一旦图像完成加载，就会显示图像。这是代码：

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

- (CGRect)centeredFrameForScrollView:(UIScrollView *)scroll andUIView:(UIView *)rView {
  CGSize boundsSize = scroll.bounds.size;
  CGRect frameToCenter = rView.frame;
  // center horizontally
  if (frameToCenter.size.width < boundsSize.width) {
    frameToCenter.origin.x = (boundsSize.width - frameToCenter.size.width) / 2;
  }
  else {
    frameToCenter.origin.x = 0;
  }
  // center vertically
  if (frameToCenter.size.height < boundsSize.height) {
    frameToCenter.origin.y = (boundsSize.height - frameToCenter.size.height) / 2;
  }
  else {
    frameToCenter.origin.y = 0;
  }
  return frameToCenter;
}

-(void)scrollViewDidZoom:(UIScrollView *)scrollView
{
  self.theImageView.frame = [self centeredFrameForScrollView:self.theScrollView andUIView:self.theImageView];                               
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
  [self.resourceData setLength:0];
  self.filesize = [NSNumber numberWithLongLong:[response expectedContentLength]];
}

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
  [self.resourceData appendData:data];
  NSNumber *resourceLength = [NSNumber numberWithUnsignedInteger:[self.resourceData length]];
  self.progressBar.progress = [resourceLength floatValue] / [self.filesize floatValue];
}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
  self.theImage = [[UIImage alloc]initWithData:resourceData];
  self.theImageView.frame = CGRectMake(0, 0, self.theImage.size.width, self.theImage.size.height);
  self.theImageView.image = self.theImage;
  self.theScrollView.minimumZoomScale = self.theScrollView.frame.size.width / self.theImageView.frame.size.width;
  self.theScrollView.maximumZoomScale = 2.0;
  [self.theScrollView setZoomScale:self.theScrollView.minimumZoomScale];
  self.theScrollView.contentSize = self.theImageView.frame.size;
  self.theLabel.hidden = YES;
  self.progressBar.hidden = YES;
}

-(void)setImageInImageView
{
  NSURLRequest *req = [[NSURLRequest alloc]initWithURL:[NSURL URLWithString:self.imageLink]];
  NSURLConnection *conn = [[NSURLConnection alloc]initWithRequest:req delegate:self];
  if (conn)
  {
    self.resourceData = [NSMutableData data];
  }
  else
  {
    NSLog(@"Connection failed: IMageViewerViewController");
  }
}

-(void)loadView
{
  self.filesize = [[NSNumber alloc]init];
  self.progressBar = [[UIProgressView alloc]initWithProgressViewStyle:UIProgressViewStyleBar];
  self.progressBar.frame = CGRectMake(20, 240, 280, 40);
  [self.progressBar setProgress:0.0];
  self.theImageView = [[[UIImageView alloc]initWithFrame:[[UIScreen mainScreen]applicationFrame]]autorelease];
  self.theScrollView = [[[UIScrollView alloc]initWithFrame:[[UIScreen mainScreen]applicationFrame]]autorelease];
  self.theScrollView.delegate = self;
  [self.theScrollView addSubview:self.theImageView];
  self.view = self.theScrollView;
  self.theLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, 200, 320, 40)];
  self.theLabel.font = [UIFont boldSystemFontOfSize:15.0f];
  self.theLabel.text = @"Please wait, file is being downloaded";
  self.theLabel.textAlignment = UITextAlignmentCenter;
  self.theLabel.hidden = NO;
  [self.view addSubview:self.progressBar];
  [self.view bringSubviewToFront:self.progressBar];
  [self.view addSubview:self.theLabel];
  [self.view bringSubviewToFront:self.    theLabel];
  [self performSelectorOnMainThread:@selector(setImageInImageView) withObject:nil waitUntilDone:NO];
}

头文件：

@interface ImageViewerViewController : UIViewController<UIScrollViewDelegate, NSURLConnectionDelegate, NSURLConnectionDataDelegate>

@property (nonatomic, retain) IBOutlet UIImageView *theImageView;
@property (nonatomic, retain) IBOutlet UIScrollView *theScrollView;
@property (nonatomic, retain) NSString *imageLink;
@property (nonatomic, retain) UIImage *theImage;
@property (nonatomic, retain) UILabel *theLabel;
@property (nonatomic, retain) UIProgressView *progressBar;
@property (nonatomic, retain) NSMutableData *resourceData;
@property (nonatomic, retain) NSNumber *filesize;
@end

希望有所帮助

Answer 4

我想这个答案可能是不必要的，但我遇到了与@adit类似的问题，并以一种非常简单的方式解决了它（我认为），也许有类似挑战的人可以使用它：

- (void)viewDidLoad {
    [super viewDidLoad];

    self.view.backgroundColor = [UIColor yellowColor];

    UIImage *imageToLoad = [UIImage imageNamed:@"background_green"];

    self.myImageView = [[UIImageView alloc]initWithImage:imageToLoad];
    self.myScrollView = [[UIScrollView alloc]initWithFrame:self.view.bounds];
    [self.myScrollView addSubview:self.myImageView];
    self.myScrollView.contentSize = self.myImageView.bounds.size;
    self.myScrollView.indicatorStyle = UIScrollViewIndicatorStyleWhite;
    self.myScrollView.minimumZoomScale = 0.3f;
    self.myScrollView.maximumZoomScale = 3.0f;
    self.myScrollView.delegate = self;
    [self.view addSubview:self.myScrollView];
}

- (UIView *) viewForZoomingInScrollView:(UIScrollView *)scrollView {
    NSLog(@"viewForZoomingInScrollView");
    return self.myImageView;
}

我的问题非常简单，我忘记添加self.myScrollView.delegate = self;，这就是我遇到问题的原因。我花了很长时间才想出这个简单的问题，我想我没有看到所有树木的福雷斯特： - ）

Answer 5

当我在UIScrollView中开发我的缩放PDF查看器时，我发现当在手机上运行时，它实际上已经将缩放实现为手机的一部分。但是你可以看看这个，http://developer.apple.com/library/ios/#samplecode/ZoomingPDFViewer/Introduction/Intro.html它是一段试图实现缩放功能的示例代码，这是希望让我开始。

Answer 6

对于“将图像捕捉到屏幕边缘”解决方案@Shrikant Tanwade的效果很好，但是我想要一些插图。我尝试了设置约束的常量，但这没用。

我以以下解决方案结束了

与Shrikant的相同-设置scrollView，imageView的约束，将其常量设置为0。
使用scrollView.contentInset = UIEdgeInsetsMake(....

UIImageView和UIScrollView缩放

6 个答案: