我正在浏览 iPhone WWDC 2010 - 104 PhotoScroller App 的示例代码。它适用于我的项目相关图像（PDF 页面图像）
但我正在努力检测 PhotoScroller 应用程序中的触摸。使用多个触摸的缩放由 ScrollVoiew 处理。现在我想在双击时放大/缩小照片。在 TilingView 类中调用 Touchesbegan 方法。然后我使用 [super touchesbegan: withevent:] 现在触摸在 ImageScrollView 类中。
如何在 PhotoViewController 中获取这些触摸事件。如何实现触摸放大和缩小？
任何人都可以在这方面提供帮助吗？
我研究了几个不同的网站，我想出了以下...
将此代码放入您的 viewDidLoad 或 viewWillAppear 方法中：
//////////////////////////////
// Listen for Double Tap Zoom
UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDoubleTap:)];
[doubleTap setNumberOfTapsRequired:2];
[self.scrollView addGestureRecognizer:doubleTap];
[doubleTap release];
将此添加到您的头文件中：
- (void)handleDoubleTap:(UIGestureRecognizer *)gestureRecognizer;
将此添加到您的实现中：
- (void)handleDoubleTap:(UIGestureRecognizer *)gestureRecognizer {
if(self.scrollView.zoomScale > self.scrollView.minimumZoomScale)
[self.scrollView setZoomScale:self.scrollView.minimumZoomScale animated:YES];
else
[self.scrollView setZoomScale:self.scrollView.maximumZoomScale animated:YES];
}
目前，这并不以用户双击的区域为中心。
我的代码，基于链接“ UIImageView 不缩放”中的一些代码 此代码处理放大和缩小之间的切换，并允许检测单击和双击。它还通过在其上应用视图变换正确地将缩放集中在嵌入图像上。此代码将进入示例代码中的 ImageScrollView 类。
- (void)setupGestureRecognisers:(UIView *)viewToAttach {
UITapGestureRecognizer *dblRecognizer;
dblRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self
action:@selector(handleDoubleTapFrom:)];
[dblRecognizer setNumberOfTapsRequired:2];
[viewToAttach addGestureRecognizer:dblRecognizer];
self.doubleTapRecognizer = dblRecognizer;
UITapGestureRecognizer *recognizer;
recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self
action:@selector(handleTapFrom:)];
[recognizer requireGestureRecognizerToFail:dblRecognizer];
[viewToAttach addGestureRecognizer:recognizer];
self.tapRecognizer = recognizer;
}
- (void)handleTapFrom:(UITapGestureRecognizer *)recognizer {
// do your single tap
}
- (CGRect)zoomRectForScale:(float)scale withCenter:(CGPoint)center {
CGRect zoomRect;
zoomRect.size.height = [_imageView frame].size.height / scale;
zoomRect.size.width = [_imageView frame].size.width / scale;
center = [_imageView convertPoint:center fromView:self];
zoomRect.origin.x = center.x - ((zoomRect.size.width / 2.0));
zoomRect.origin.y = center.y - ((zoomRect.size.height / 2.0));
return zoomRect;
}
- (void)handleDoubleTapFrom:(UITapGestureRecognizer *)recognizer {
float newScale = [self zoomScale] * 4.0;
if (self.zoomScale > self.minimumZoomScale)
{
[self setZoomScale:self.minimumZoomScale animated:YES];
}
else
{
CGRect zoomRect = [self zoomRectForScale:newScale
withCenter:[recognizer locationInView:recognizer.view]];
[self zoomToRect:zoomRect animated:YES];
}
}
这是一个基于@possen出色答案的Swift解决方案。
- 将它放在包含滚动视图并且是滚动视图委托的视图控制器中。
- 这个解决方案很棒，因为它实际上会缩放到点击位置：
@IBAction func handleDoubleTapScrollView(recognizer: UITapGestureRecognizer) {
if scrollView.zoomScale == 1 {
scrollView.zoom(to: zoomRectForScale(scale: scrollView.maximumZoomScale, center: recognizer.location(in: recognizer.view)), animated: true)
} else {
scrollView.setZoomScale(1, animated: true)
}
}
func zoomRectForScale(scale: CGFloat, center: CGPoint) -> CGRect {
var zoomRect = CGRect.zero
zoomRect.size.height = imageView.frame.size.height / scale
zoomRect.size.width = imageView.frame.size.width / scale
let newCenter = scrollView.convert(center, from: imageView)
zoomRect.origin.x = newCenter.x - (zoomRect.size.width / 2.0)
zoomRect.origin.y = newCenter.y - (zoomRect.size.height / 2.0)
return zoomRect
}
斯威夫特 3
通常，双击和捏合手势都需要图像缩放功能，因此我提供了完整的解决方案来实现相同的功能。双击缩放受上述答案的启发，捏缩放取自此处。
import UIKit
class ViewController: UIViewController, UIScrollViewDelegate {
var imageView: UIImageView!
var scrollImg: UIScrollView!
override func viewDidLoad() {
super.viewDidLoad()
let vWidth = self.view.frame.width
let vHeight = self.view.frame.height
scrollImg = UIScrollView()
scrollImg.delegate = self
scrollImg.frame = CGRect(x: 0, y: 0, width: vWidth, height: vHeight)
scrollImg.backgroundColor = UIColor(red: 90, green: 90, blue: 90, alpha: 0.90)
scrollImg.alwaysBounceVertical = false
scrollImg.alwaysBounceHorizontal = false
scrollImg.showsVerticalScrollIndicator = true
scrollImg.flashScrollIndicators()
scrollImg.minimumZoomScale = 1.0
scrollImg.maximumZoomScale = 10.0
let doubleTapGest = UITapGestureRecognizer(target: self, action: #selector(handleDoubleTapScrollView(recognizer:)))
doubleTapGest.numberOfTapsRequired = 2
scrollImg.addGestureRecognizer(doubleTapGest)
self.view.addSubview(scrollImg)
imageView = UIImageView(frame: CGRect(x: 0, y: 0, width: vWidth, height: vHeight))
imageView.image = UIImage(named: "cat")
imageView!.layer.cornerRadius = 11.0
imageView!.clipsToBounds = false
scrollImg.addSubview(imageView!)
}
func handleDoubleTapScrollView(recognizer: UITapGestureRecognizer) {
if scrollImg.zoomScale == 1 {
scrollImg.zoom(to: zoomRectForScale(scale: scrollImg.maximumZoomScale, center: recognizer.location(in: recognizer.view)), animated: true)
} else {
scrollImg.setZoomScale(1, animated: true)
}
}
func zoomRectForScale(scale: CGFloat, center: CGPoint) -> CGRect {
var zoomRect = CGRect.zero
zoomRect.size.height = imageView.frame.size.height / scale
zoomRect.size.width = imageView.frame.size.width / scale
let newCenter = imageView.convert(center, from: scrollImg)
zoomRect.origin.x = newCenter.x - (zoomRect.size.width / 2.0)
zoomRect.origin.y = newCenter.y - (zoomRect.size.height / 2.0)
return zoomRect
}
func viewForZooming(in scrollView: UIScrollView) -> UIView? {
return self.imageView
}
}
我将@jayesh kavathiya 和@possen 的答案组合成一个运行良好的实现，只要您为self.minimumZoomScaleand设置了适当的值self.maximumZoomScale。
- (void)doubleTap:(UITapGestureRecognizer*)recognizer
{
if (self.zoomScale > self.minimumZoomScale)
{
[self setZoomScale:self.minimumZoomScale animated:YES];
}
else
{
CGPoint touch = [recognizer locationInView:recognizer.view];
CGSize scrollViewSize = self.bounds.size;
CGFloat w = scrollViewSize.width / self.maximumZoomScale;
CGFloat h = scrollViewSize.height / self.maximumZoomScale;
CGFloat x = touch.x-(w/2.0);
CGFloat y = touch.y-(h/2.0);
CGRect rectTozoom=CGRectMake(x, y, w, h);
[self zoomToRect:rectTozoom animated:YES];
}
}
使用此代码，它会在您单击的位置缩放.......
- (void)handleDoubleTap:(UIGestureRecognizer *)recognizer {
if(zoomCheck){
CGPoint Pointview=[recognizer locationInView:self];
CGFloat newZoomscal=3.0;
newZoomscal=MIN(newZoomscal, self.maximumZoomScale);
CGSize scrollViewSize=self.bounds.size;
CGFloat w=scrollViewSize.width/newZoomscal;
CGFloat h=scrollViewSize.height /newZoomscal;
CGFloat x= Pointview.x-(w/2.0);
CGFloat y = Pointview.y-(h/2.0);
CGRect rectTozoom=CGRectMake(x, y, w, h);
[self zoomToRect:rectTozoom animated:YES];
[self setZoomScale:3.0 animated:YES];
zoomCheck=NO;
}
else{
[self setZoomScale:1.0 animated:YES];
zoomCheck=YES;
}
}
使用此代码，它会在您单击的位置缩放....... zoomChech 是用于检查缩放的布尔变量
使用BlocksKit之前的答案可能会更简单，如下所示。
#import "BlocksKit.h"
...
UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithHandler:^(UIGestureRecognizer *sender, UIGestureRecognizerState state, CGPoint location) {
if(scrollView.zoomScale != 1.0){
[scrollView setZoomScale:1.0 animated:YES];
}else{
[scrollView setZoomScale:2.0 animated:YES];
}
}];
[doubleTap setNumberOfTapsRequired:2];
[scrollView addGestureRecognizer:doubleTap];
您需要实施viewForZooming(in scrollView: UIScrollView) -> UIView? in UIScrollViewDelegate才能使@n8tr 的答案正常工作。
所以完整的代码看起来像这样
class ViewController: UIViewController, UIScrollViewDelegate {
@IBOutlet weak var scrollView: UIScrollView!
@IBOutlet weak var imageView: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
scrollView.delegate = self
}
@IBAction func handleDoubleTapScrollView(recognizer: UITapGestureRecognizer) {
if scrollView.zoomScale == 1 {
scrollView.zoom(to: zoomRectForScale(scale: scrollView.maximumZoomScale, center: recognizer.location(in: recognizer.view)), animated: true)
} else {
scrollView.setZoomScale(1, animated: true)
}
}
func zoomRectForScale(scale: CGFloat, center: CGPoint) -> CGRect {
var zoomRect = CGRect.zero
zoomRect.size.height = imageView.frame.size.height / scale
zoomRect.size.width = imageView.frame.size.width / scale
let newCenter = imageView.convert(center, from: scrollView)
zoomRect.origin.x = newCenter.x - (zoomRect.size.width / 2.0)
zoomRect.origin.y = newCenter.y - (zoomRect.size.height / 2.0)
return zoomRect
}
func viewForZooming(in scrollView: UIScrollView) -> UIView? {
return imageView
}
}
它是 swift 5 的最新代码，用于双指缩放和双击缩放。
import UIKit
class ViewController: UIViewController, UIScrollViewDelegate {
@IBOutlet weak var scrollView: UIScrollView!
@IBOutlet weak var imageView: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
scrollView.delegate = self
let doubleTapGest = UITapGestureRecognizer(target: self, action: #selector(handleDoubleTapScrollView(recognizer:)))
doubleTapGest.numberOfTapsRequired = 2
scrollView.addGestureRecognizer(doubleTapGest)
}
func viewForZooming(in scrollView: UIScrollView) -> UIView? {
return imageView
}
@objc func handleDoubleTapScrollView(recognizer: UITapGestureRecognizer) {
if scrollView.zoomScale == 1 {
scrollView.zoom(to: zoomRectForScale(scale: scrollView.maximumZoomScale, center: recognizer.location(in: recognizer.view)), animated: true)
}
else {
scrollView.setZoomScale(1, animated: true)
}
}
func zoomRectForScale(scale: CGFloat, center: CGPoint) -> CGRect {
var zoomRect = CGRect.zero
zoomRect.size.height = imageView.frame.size.height / scale
zoomRect.size.width = imageView.frame.size.width / scale
let newCenter = imageView.convert(center, from: scrollView)
zoomRect.origin.x = newCenter.x - (zoomRect.size.width / 2.0)
zoomRect.origin.y = newCenter.y - (zoomRect.size.height / 2.0)
return zoomRect
}
}
我也附上了故事板图片。
将 UITapGestureRecognizer 添加到 ImageScrollView 怎么样？
只要你在看示例代码，就可以查看ScrollViewSuite 示例代码中 UIGestureRecognizers 是如何使用的。
在 m 文件中添加 UIScrollView 的子类
#pragma mark -
#pragma mark doubleTouch
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
NSUInteger tapCount = [touch tapCount];
switch (tapCount) {
case 2:
{
if(self.zoomScale <1.0){
[self setZoomScale:1.0 animated:YES];
}else{
[self setZoomScale:0.1 animated:YES];
}
break;
}
default:
break;
}
}
这似乎可以使用convertRect:fromView:and工作zoomToRect:animated:：
-(void)tap:(UITapGestureRecognizer *)tapGestureRecognizer
{
CGFloat zoomeScaleMultiplier = 0.5;
UIScrollView *scrollView = (UIScrollView *) tapGestureRecognizer.view;
UIView *zoomableView = [scrollView.delegate viewForZoomingInScrollView:scrollView];
CGRect rect = scrollView.bounds;
rect.origin = CGPointZero;
CGAffineTransform transform = CGAffineTransformMakeScale(zoomeScaleMultiplier, zoomeScaleMultiplier);
rect = CGRectApplyAffineTransform(rect, transform);
rect.origin = [tapGestureRecognizer locationInView:scrollView];
rect = CGRectOffset(rect, CGRectGetWidth(rect)/-2., CGRectGetHeight(rect)/-2.);
rect = [zoomableView convertRect:rect fromView:scrollView];
[scrollView zoomToRect:rect animated:YES];
}
放大点击位置
CGFloat scale = 3.0;
CGFloat scale = ScaleToAspectFitRectAroundRect(frame, self.bounds) * 2.0;
CGRect zoomRect;
CGPoint point = [gestureRecognizer locationOfTouch:0 inView:[gestureRecognizer view]];
zoomRect.size.height = frame.size.height * scale;
zoomRect.size.width = frame.size.width * scale;
zoomRect.origin.x = CGRectGetMidX(frame) - (CGRectGetWidth(zoomRect)/2) + (scale * (CGRectGetWidth(frame)/2 - point.x)) - (CGRectGetWidth(frame)/2 - point.x);
zoomRect.origin.y = CGRectGetMidY(frame) - (CGRectGetHeight(zoomRect)/2) + (scale * (CGRectGetHeight(frame)/2 - point.y)) - (CGRectGetHeight(frame)/2 - point.y);
这里我的代码对我有用，很简单：
// Listen for Double Tap Zoom
UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDoubleTap:)];
[doubleTap setNumberOfTapsRequired:2];
[self addGestureRecognizer:doubleTap];
你需要
BOOL checkZoomImage;
这里选项卡方法
- (void)handleDoubleTap:(UIGestureRecognizer *)gestureRecognizer {
if (self.zoomScale > self.minimumZoomScale && self.zoomScale == self.maximumZoomScale){
checkZoomImage = YES;
}
if (self.zoomScale < self.maximumZoomScale && self.zoomScale == self.minimumZoomScale) {
checkZoomImage = NO;
}
if (checkZoomImage) {
[self setZoomScale:self.zoomScale *0.5 animated:YES];
}else{
[self setZoomScale:self.zoomScale *1.5 animated:YES];
}
}