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标题: ios - 如何正确拖放、旋转和缩放 UIView？ [打印本页]

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作者: 菜鸟教程小白    时间: 2022-12-13 10:48
标题: ios - 如何正确拖放、旋转和缩放 UIView？

在我的 iOS 应用程序中，我使用 UITouchGestureRecognizer 拖放、缩放和旋转 UIImageView。我还将信息存储在 ImageView 的最后位置，以便在应用重新启动时检索它。

这在 iOS7 上运行良好，但我最近开始在 iOS8 上进行测试，但遇到了一些问题，尤其是在缩放方面。每当 ImageView 在旋转参数中具有非 0 角度时，缩放就不会像预期的那样起作用并减小图像的大小。

我不明白操作系统为什么会这样，这是我的代码:

-(void) viewDidAppearBOOL)animated{
    [super viewDidAppear:YES];
    [self loadAllImages];
    for (GIFavorite *favorite in self.favorites){
        UIImage *image = favorite.image;
        ImageView *imageView = [[ImageView alloc] initWithFrame:CGRectMake(0, 0, image.size.width, image.size.height)];
        imageView.center = CGPointMake(favorite.x, favorite.y);
        imageView.transform = CGAffineTransformMakeRotation(favorite.rotation);
        imageView.transform = CGAffineTransformScale(imageView.transform, favorite.scale, favorite.scale);
        imageView.image = image;
        imageView.userInteractionEnabled = YES;
        UIPanGestureRecognizer * panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self actionselector(handlePan];
        panRecognizer.delegate = self;
        [imageView addGestureRecognizer:panRecognizer];
        UIRotationGestureRecognizer * rotationRecognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self actionselector(handleRotate];
        rotationRecognizer.delegate = self;
        [imageView addGestureRecognizer:rotationRecognizer];
        UIPinchGestureRecognizer * pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self actionselector(handlePinch];
        pinchRecognizer.delegate = self;
        [imageView addGestureRecognizer:pinchRecognizer];
        [self.view addSubview:imageView];
    }
}

我猜我进行转换的方式是错误的，因为当我将 CGAffineTransformMakeRotation 指令放在 CGAffineTransformScale 之后而不是减小大小时，它会增加它。

我哪里做错了？

编辑:handleRotate 的代码

- (void)handleRotateUIRotationGestureRecognizer *)recognizer {
    recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation);
    ImageView *imageView = recognizer.view;
    CGFloat radians = atan2f(imageView.transform.b, imageView.transform.a);
    favorite.rotation = radians;
    recognizer.rotation = 0;
}

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Best Answer-推荐答案

首先，你需要让你的 View Controller 实现 UIGestureRecognizerDelegate。

SWIFT 3:-

func setUpGestures () {

    let panGesture = UIPanGestureRecognizer(target: self, action:#selector(self.handlePanGesture(gesture))
    self.imageView.addGestureRecognizer(panGesture)

    let rotationGesture = UIRotationGestureRecognizer(target: self, action:#selector(self.handleRotationGesture(gesture))
    self.imageView.addGestureRecognizer(rotationGesture)

    let pinchGesture = UIPinchGestureRecognizer(target: self, action:#selector(self.handlePinchGesture(gesture))
    self.imageView.addGestureRecognizer(pinchGesture)
}

func handlePinchGesture(gesture: UIPinchGestureRecognizer) {
    if gesture.state == UIGestureRecognizerState.began || gesture.state == UIGestureRecognizerState.changed{
        //print("UIPinchGestureRecognizer")
        gesture.view?.transform = (gesture.view?.transform)!.scaledBy(x: gesture.scale, y: gesture.scale)
        gesture.scale = 1.0
    }
}

func handleRotationGesture(gesture: UIRotationGestureRecognizer) {
    if gesture.state == UIGestureRecognizerState.began || gesture.state == UIGestureRecognizerState.changed{
        //print("UIRotationGestureRecognizer")
        gesture.view?.transform = (gesture.view?.transform)!.rotated(by: gesture.rotation)
        gesture.rotation = 0
    }
}

func handlePanGesture(gesture: UIPanGestureRecognizer) {
    if gesture.state == UIGestureRecognizerState.began || gesture.state == UIGestureRecognizerState.changed{
        //print("UIPanGestureRecognizer")
        let translation = gesture.translation(in: view)
        gesture.view?.transform = (gesture.view?.transform)!.translatedBy(x: translation.x, y: translation.y)
        gesture.setTranslation(CGPoint(x: 0, y: 0), in: view)
    }
}

希望，这就是您要找的。任何问题都可以回复我。

关于ios - 如何正确拖放、旋转和缩放 UIView？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32538629/

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