双击放大/缩小

Question

我有一个应用程序，当用户从文本列表视图屏幕按下按钮时，它会显示一堆图片。我有一个特定的子类，允许用户捏合和放大，但我很好奇我需要在我的特定 swift 文件中输入什么代码以允许用户双击放大和缩小。使用此代码时出现三个错误。两个说“'ZoomingScrollView'类型的值没有成员'scrollview'或'imageview'”以及“'CGRectZero'在Swift中不可用”我允许用户放大的子类代码和我的代码一起在下面我正在使用双击缩放。

import UIKit

class ZoomingScrollView: UIScrollView, UIScrollViewDelegate {

 @IBOutlet weak var viewForZooming: UIView? = nil {
didSet {
    self.delegate = self
} }

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

@IBAction func userDoubleTappedScrollview(recognizer:  UITapGestureRecognizer) {
if let scrollV = self.scrollview {
    if (scrollV.zoomScale > scrollV.minimumZoomScale) {
        scrollV.setZoomScale(scrollV.minimumZoomScale, animated: true)
    }
    else {
        //(I divide by 3.0 since I don't wan't to zoom to the max upon the double tap)
        let zoomRect = self.zoomRectForScale(scrollV.maximumZoomScale / 3.0, center: recognizer.locationInView(recognizer.view))
        self.scrollview?.zoomToRect(zoomRect, animated: true)
    }
} }

func zoomRectForScale(scale : CGFloat, center : CGPoint) -> CGRect {
var zoomRect = CGRectZero
if let imageV = self.imageView {
    zoomRect.size.height = imageV.frame.size.height / scale;
    zoomRect.size.width  = imageV.frame.size.width  / scale;
    let newCenter = imageV.convertPoint(center, fromView: self.scrollview)
    zoomRect.origin.x = newCenter.x - ((zoomRect.size.width / 2.0));
    zoomRect.origin.y = newCenter.y - ((zoomRect.size.height / 2.0));
}
return zoomRect; }}

Answer 1

问题似乎是您从具有 scrollView 和 imageView 插座的视图控制器中复制了一些代码。我猜你的 viewForZooming: UIView 是你正在放大的图像视图。您也不必再引用 self.scrollView 因为 self 是滚动视图，因为您正在继承滚动视图 :) 我认为下面的代码应该可以解决您的问题（注意：它采用最新的 swift 语法。您发布的是不是，因此您可能需要在必要时将代码切换回旧样式。不过，您应该尝试使用最新的 Swift）。祝你好运，如果你有问题，请告诉我。

import UIKit

class ZoomingScrollView: UIScrollView, UIScrollViewDelegate {

    @IBOutlet weak var viewForZooming: UIView? = nil {
        didSet {
            self.delegate = self
        } }

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

    @IBAction func userDoubleTappedScrollview(recognizer:  UITapGestureRecognizer) {
        if (zoomScale > minimumZoomScale) {
            setZoomScale(minimumZoomScale, animated: true)
        }
        else {
            //(I divide by 3.0 since I don't wan't to zoom to the max upon the double tap)
            let zoomRect = zoomRectForScale(scale: maximumZoomScale / 3.0, center: recognizer.location(in: recognizer.view))
            zoom(to: zoomRect, animated: true)
        }
    }

    func zoomRectForScale(scale : CGFloat, center : CGPoint) -> CGRect {
        var zoomRect = CGRect.zero
        if let imageV = self.viewForZooming {
            zoomRect.size.height = imageV.frame.size.height / scale;
            zoomRect.size.width  = imageV.frame.size.width  / scale;
            let newCenter = imageV.convert(center, from: self)
            zoomRect.origin.x = newCenter.x - ((zoomRect.size.width / 2.0));
            zoomRect.origin.y = newCenter.y - ((zoomRect.size.height / 2.0));
        }
        return zoomRect;
    }
}