IOS：在滚动视图中添加的ImageView有放大(IOS: add imageview in a

2019-06-26 00:33发布

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我想设置有一个UIImageView UIImage ，并把这个ImageView的一个内部UIScrollView获得此图像的缩放; 我想这个UIImageView和UIScrollView以适应矩形在视图的中心......这可能吗？

Answer 1:

  1. 设置您的视图控制器最多可为<UIScrollViewDelegate>
  2. 画出你UIScrollView你想在视图的中心矩形的大小。 在检查器中设置最大变焦比的东西大1 4一样或10。
  3. 右键单击滚动视图和代理连接到您的视图控制器。
  4. 画出你UIImageView的UIScrollView和你想要的任何图像设置。 让它同样大小的UIScrollView 。
  5. 您按Ctrl +拖动形式UIImageView到.h您的视图控制器创建的IBOutlet为UIImageView ，叫它一些聪明像imageView 。

  6. 添加以下代码： 

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

  7. 运行应用程序，捏和平移直到你的心脏的内容。



Answer 2:

下载这个和这个文件。 你需要他们处理的一面。

添加到您的视图滚动视图代表<UIScrollViewDelegate>并声明网点： 

 @property (nonatomic, retain) IBOutlet UIScrollView *imageScrollView;
 @property (nonatomic, retain) UIImageView *imageView;

导入下载的文件里面的画面，并做到： 

#import "TapDetectingImageView.h"

#define ZOOM_STEP 2.0
@interface myView (UtilityMethods)
- (CGRect)zoomRectForScale:(float)scale withCenter:(CGPoint)center;
@end


@implementation myView
@synthesize imageScrollView, imageView;


- (void)viewDidLoad
{

    [super viewDidLoad];

    //Setting up the scrollView    
    imageScrollView.bouncesZoom = YES;
    imageScrollView.delegate = self;
    imageScrollView.clipsToBounds = YES;

    //Setting up the imageView
    imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"myImage.png"]];
    imageView.userInteractionEnabled = YES;
    imageView.autoresizingMask = ( UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin);

    //Adding the imageView to the scrollView as subView
    [imageScrollView addSubview:imageView];
    imageScrollView.contentSize = CGSizeMake(imageView.bounds.size.width, imageView.bounds.size.height);
    imageScrollView.decelerationRate = UIScrollViewDecelerationRateFast;

    //UITapGestureRecognizer set up
    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];

    //Adding gesture recognizer
    [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 = 1.0;//This is the minimum scale, set it to whatever you want. 1.0 = default
    imageScrollView.maximumZoomScale = 4.0;
    imageScrollView.minimumZoomScale = minimumScale;
    imageScrollView.zoomScale = minimumScale;
    [imageScrollView setContentMode:UIViewContentModeScaleAspectFit];
    [imageView sizeToFit];
    [imageScrollView setContentSize:CGSizeMake(imageView.frame.size.width, imageView.frame.size.height)];



}

- (void)scrollViewDidZoom:(UIScrollView *)aScrollView {
    CGFloat offsetX = (imageScrollView.bounds.size.width > imageScrollView.contentSize.width)? 
    (imageScrollView.bounds.size.width - imageScrollView.contentSize.width) * 0.5 : 0.0;
    CGFloat offsetY = (imageScrollView.bounds.size.height > imageScrollView.contentSize.height)? 
    (imageScrollView.bounds.size.height - imageScrollView.contentSize.height) * 0.5 : 0.0;
    imageView.center = CGPointMake(imageScrollView.contentSize.width * 0.5 + offsetX, 
                                   imageScrollView.contentSize.height * 0.5 + offsetY);
}

- (void)viewDidUnload {
    self.imageScrollView = nil;
    self.imageView = nil;
}



#pragma mark UIScrollViewDelegate methods

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

#pragma mark TapDetectingImageViewDelegate methods

- (void)handleDoubleTap:(UIGestureRecognizer *)gestureRecognizer {
    // zoom in
    float newScale = [imageScrollView zoomScale] * ZOOM_STEP;

    if (newScale > self.imageScrollView.maximumZoomScale){
        newScale = self.imageScrollView.minimumZoomScale;
        CGRect zoomRect = [self zoomRectForScale:newScale withCenter:[gestureRecognizer locationInView:gestureRecognizer.view]];

        [imageScrollView zoomToRect:zoomRect animated:YES];

    }
    else{

        newScale = self.imageScrollView.maximumZoomScale;
        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;

    // the zoom rect is in the content view's coordinates. 
    //    At a zoom scale of 1.0, it would be the size of the imageScrollView's bounds.
    //    As the zoom scale decreases, so more content is visible, the size of the rect grows.
    zoomRect.size.height = [imageScrollView frame].size.height / scale;
    zoomRect.size.width  = [imageScrollView frame].size.width  / scale;

    // choose an origin so as to get the right center.
    zoomRect.origin.x    = center.x - (zoomRect.size.width  / 2.0);
    zoomRect.origin.y    = center.y - (zoomRect.size.height / 2.0);

    return zoomRect;
}

完成！

基本上这代码做的是将增加imageView作为子视图imageScrollView 。

然后，它会将TapDetecting类的方法来滚动视图，以识别抽头数-掐用户做并添加缩放功能。

您可以设置minimumScale的形象，如果你离开1.0图像应显示为-IT-是（如果你将它设置低一点它被缩放），以及maximumZoomScale ，我建议你把它留给4，没关系！

现在，你可以从那里编程方式加载图像。

你必须做的最后一件事是插入一个UIScrollView您的XIB文件中，并将其链接到imageScrollView 。 你必须在完善中心的形象，你可以在上面枪王变焦，捏放大，你在代码中设置。



Answer 3:

随着斯威夫特4和iOS 11，可以使用以下两种解决方案之一，以解决您的问题。

＃1。 使用插图

ViewController.swift 

import UIKit

final class ViewController: UIViewController {

    private let scrollView = ImageScrollView(image: UIImage(named: "image")!)

    override func viewDidLoad() {
        view.backgroundColor = .black
        view.addSubview(scrollView)

        scrollView.frame = view.frame
        scrollView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
    }

}

ImageScrollView.swift 

import UIKit

final class ImageScrollView: UIScrollView {

    private let imageView = UIImageView()
    override var frame: CGRect {
        didSet {
            if frame.size != oldValue.size { setZoomScale() }
        }
    }

    required init(image: UIImage) {
        super.init(frame: .zero)

        imageView.image = image
        imageView.sizeToFit()
        addSubview(imageView)
        contentSize = imageView.bounds.size

        contentInsetAdjustmentBehavior = .never // Adjust content according to safe area if necessary
        showsVerticalScrollIndicator = false
        showsHorizontalScrollIndicator = false
        alwaysBounceHorizontal = true
        alwaysBounceVertical = true
        delegate = self
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    // MARK: - Helper methods

    func setZoomScale() {
        let widthScale = frame.size.width / imageView.bounds.width
        let heightScale = frame.size.height / imageView.bounds.height
        let minScale = min(widthScale, heightScale)
        minimumZoomScale = minScale
        zoomScale = minScale
    }

}

extension ImageScrollView: UIScrollViewDelegate {

    func viewForZooming(in scrollView: UIScrollView) -> UIView? {
        return imageView
    }

    func scrollViewDidZoom(_ scrollView: UIScrollView) {
        let imageViewSize = imageView.frame.size
        let scrollViewSize = scrollView.bounds.size
        let verticalInset = imageViewSize.height < scrollViewSize.height ? (scrollViewSize.height - imageViewSize.height) / 2 : 0
        let horizontalInset = imageViewSize.width < scrollViewSize.width ? (scrollViewSize.width - imageViewSize.width) / 2 : 0
        scrollView.contentInset = UIEdgeInsets(top: verticalInset, left: horizontalInset, bottom: verticalInset, right: horizontalInset)
    }

}

＃2。 使用自动布局

ViewController.swift 

import UIKit

final class ViewController: UIViewController {

    private let scrollView = ImageScrollView(image: UIImage(named: "image")!)

    override func viewDidLoad() {
        view.backgroundColor = .black
        view.addSubview(scrollView)

        scrollView.translatesAutoresizingMaskIntoConstraints = false
        scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
        scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
        scrollView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
        scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
    }

    override func viewDidLayoutSubviews() {        
        scrollView.setZoomScale()
    }

}

ImageScrollView.swift 

import UIKit

final class ImageScrollView: UIScrollView {

    private let imageView = UIImageView()
    private var imageViewBottomConstraint = NSLayoutConstraint()
    private var imageViewLeadingConstraint = NSLayoutConstraint()
    private var imageViewTopConstraint = NSLayoutConstraint()
    private var imageViewTrailingConstraint = NSLayoutConstraint()

    required init(image: UIImage) {
        super.init(frame: .zero)

        imageView.image = image
        imageView.sizeToFit()
        addSubview(imageView)

        imageView.translatesAutoresizingMaskIntoConstraints = false
        imageViewLeadingConstraint = imageView.leadingAnchor.constraint(equalTo: leadingAnchor)
        imageViewTrailingConstraint = imageView.trailingAnchor.constraint(equalTo: trailingAnchor)
        imageViewTopConstraint = imageView.topAnchor.constraint(equalTo: topAnchor)
        imageViewBottomConstraint = imageView.bottomAnchor.constraint(equalTo: bottomAnchor)
        NSLayoutConstraint.activate([imageViewLeadingConstraint, imageViewTrailingConstraint, imageViewTopConstraint, imageViewBottomConstraint])

        contentInsetAdjustmentBehavior = .never // Adjust content according to safe area if necessary
        showsVerticalScrollIndicator = false
        showsHorizontalScrollIndicator = false
        alwaysBounceHorizontal = true
        alwaysBounceVertical = true
        delegate = self
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    // MARK: - Helper methods

    func setZoomScale() {
        let widthScale = frame.size.width / imageView.bounds.width
        let heightScale = frame.size.height / imageView.bounds.height
        let minScale = min(widthScale, heightScale)
        minimumZoomScale = minScale
        zoomScale = minScale
    }

}

extension ImageScrollView: UIScrollViewDelegate {

    func viewForZooming(in scrollView: UIScrollView) -> UIView? {
        return imageView
    }

    func scrollViewDidZoom(_ scrollView: UIScrollView) {
        let yOffset = max(0, (bounds.size.height - imageView.frame.height) / 2)
        imageViewTopConstraint.constant = yOffset
        imageViewBottomConstraint.constant = yOffset

        let xOffset = max(0, (bounds.size.width - imageView.frame.width) / 2)
        imageViewLeadingConstraint.constant = xOffset
        imageViewTrailingConstraint.constant = xOffset

        layoutIfNeeded()
    }

}

资料来源：

  • Github上/ ImageScrollView
  • raywenderlich.com / UIScrollView的教程：入门


Answer 4:

我已经写了一个示例应用程序还支持自动版式和故事来说明这种情况。 我希望这样可以节省大家的时间，试图弄清楚这一点： http://rexstjohn.com/facebook-like-ios-photo-modal-gallery-swipe-gestures/ 。



文章来源: IOS: add imageview in a scrollview to have zoom
标签： ios uiscrollview uiimageview uiimage
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