UIImageView 不缩放答案

【问题标题】：UIImageView does not zoomUIImageView 不缩放
【发布时间】：2012-05-27 23:51:01
【问题描述】：

我想在弹出视图上缩放图像。

我创建了 UIView 子类，基于this 示例代码：

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：

#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 delegate 之间建立了连接，但运行代码后，图像不会缩放。我忽略了什么？

【问题讨论】：

您是否在 IB 中设置了最小/最大缩放？
是的，我也设置了最小和最大缩放。
如何将手势识别器添加到滚动视图而不是封闭的图像视图？
它可以识别...我在方法中放入了一些 NSLog，它会显示出来。

标签： objective-c ios5 uiscrollview uiimageview zooming

【解决方案1】：

尝试从 imageScrollView 委托给自己。 -> imageScrollView.delegate = self;

【讨论】：

【解决方案2】：

我认为您拍摄了小图像。你必须采取更大的形象。我认为它会奏效。试试这样。

【讨论】：