UIImageView不会缩放 [英] UIImageView does not zoom

问题描述

我想在弹出视图上缩放图像。

I would like to zoom an image on a popup view.

我已经基于这个示例代码：

ZoomView.h：

ZoomView.h:

@interface ZoomView : UIView <UIScrollViewDelegate> {
    UIScrollView *imageScrollView;
    UIImageView *imageView;
}
@property (strong, nonatomic) IBOutlet UIScrollView *imageScrollView;
@property (strong, nonatomic) IBOutlet UIImageView *imageView;

@end

ZoomView.m：

ZoomView.m:

#import "ZoomView.h"

#define ZOOM_VIEW_TAG 100
#define ZOOM_STEP 1.5

@interface ZoomView (UtilityMethods)
- (CGRect)zoomRectForScale:(float)scale withCenter:(CGPoint)center;
@end

@implementation ZoomView
@synthesize imageScrollView;
@synthesize imageView;


- (void)awakeFromNib{

}

#pragma mark - View lifecycle

- (void)loadView
{
    [imageView setTag:ZOOM_VIEW_TAG];

    // add gesture recognizers to the image view
    UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleTap:)];
    UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDoubleTap:)];
    UITapGestureRecognizer *twoFingerTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTwoFingerTap:)];

    [doubleTap setNumberOfTapsRequired:2];
    [twoFingerTap setNumberOfTouchesRequired:2];

    [imageView addGestureRecognizer:singleTap];
    [imageView addGestureRecognizer:doubleTap];
    [imageView addGestureRecognizer:twoFingerTap];

    [singleTap release];
    [doubleTap release];
    [twoFingerTap release];

    // calculate minimum scale to perfectly fit image width, and begin at that scale
    float minimumScale = [imageScrollView frame].size.width  / [imageView frame].size.width;
    [imageScrollView setMinimumZoomScale:minimumScale];
    [imageScrollView setZoomScale:minimumScale];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return YES;
}

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
    return [imageScrollView viewWithTag:ZOOM_VIEW_TAG];
}

- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale {
    [scrollView setZoomScale:scale+0.01 animated:NO];
    [scrollView setZoomScale:scale animated:NO];
}

#pragma mark TapDetectingImageViewDelegate methods

- (void)handleSingleTap:(UIGestureRecognizer *)gestureRecognizer {
    // single tap does nothing for now
}

- (void)handleDoubleTap:(UIGestureRecognizer *)gestureRecognizer {
    // double tap zooms in
    float newScale = [imageScrollView zoomScale] * ZOOM_STEP;
    CGRect zoomRect = [self zoomRectForScale:newScale withCenter:[gestureRecognizer locationInView:gestureRecognizer.view]];
    [imageScrollView zoomToRect:zoomRect animated:YES];
}

- (void)handleTwoFingerTap:(UIGestureRecognizer *)gestureRecognizer {
    // two-finger tap zooms out
    float newScale = [imageScrollView zoomScale] / ZOOM_STEP;
    CGRect zoomRect = [self zoomRectForScale:newScale withCenter:[gestureRecognizer locationInView:gestureRecognizer.view]];
    [imageScrollView zoomToRect:zoomRect animated:YES];
}

#pragma mark Utility methods

- (CGRect)zoomRectForScale:(float)scale withCenter:(CGPoint)center {
    CGRect zoomRect;

    zoomRect.size.height = [imageScrollView frame].size.height / scale;
    zoomRect.size.width  = [imageScrollView frame].size.width  / scale;

    zoomRect.origin.x    = center.x - (zoomRect.size.width  / 2.0);
    zoomRect.origin.y    = center.y - (zoomRect.size.height / 2.0);

    return zoomRect;
}

@end

在我的nib文件中，我将视图的类设置为ZoomView，在视图， imageScrollView ， imageView 和<$ c之间建立连接$ c>委托，但在运行代码后，图像不会缩放。我省略了什么？

In my nib file, I've set the view's class to ZoomView, made the connections between the view, the imageScrollView, imageView and delegate, but after running the code, the image does not zoom. What did I omit to do?

推荐答案

我认为你拍摄的照片很小。你必须拍更大的图像。我认为它会奏效。试试这样。

I think you have taken small image. You have to take bigger image. I think it will be worked.Try like that.

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