如何正确地拖放、旋转和缩放UIView？

Question

如何正确地拖放、旋转和缩放UIView？

3

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

这在iOS7上运行良好，但最近开始在iOS8上测试时遇到了一些问题，特别是缩放方面。每当imageview在旋转参数中具有非0角度时，缩放就不像预期的那样，并且会减小图像的大小。

我不明白为什么操作系统的更改会导致这种情况，以下是我的代码：

-(void) viewDidAppear:(BOOL)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 action:@selector(handlePan:)];
        panRecognizer.delegate = self;
        [imageView addGestureRecognizer:panRecognizer];
        UIRotationGestureRecognizer * rotationRecognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(handleRotate:)];
        rotationRecognizer.delegate = self;
        [imageView addGestureRecognizer:rotationRecognizer];
        UIPinchGestureRecognizer * pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handlePinch:)];
        pinchRecognizer.delegate = self;
        [imageView addGestureRecognizer:pinchRecognizer];
        [self.view addSubview:imageView];
    }
}

我猜我执行转换的方式有误，因为当我在CGAffineTransformScale之后加上CGAffineTransformMakeRotation指令时，它会增大而不是减小尺寸。我做错了什么？

编辑: handleRotate的代码

- (void)handleRotate:(UIRotationGestureRecognizer *)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;
}

- Gannicus

3个回答

1

首先，您需要使您的视图控制器实现UIGestureRecognizerDelegate。

然后将手势识别器添加到您的UIView中（我看到您已经这样做了，但是再次放在这里以便将解决方案放在一个地方）。

UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];
panGesture.delegate = self;
UIRotationGestureRecognizer *rotationGesture = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(handleRotate:)];
rotationGesture.delegate = self;
UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handlePinch:)];
pinchGesture.delegate = self;

[yourView addGestureRecognizer:panGesture];
[yourView addGestureRecognizer:rotationGesture];
[yourView addGestureRecognizer:pinchGesture];

那么，你的handle...方法应该是这样的：

- (void)handlePinch:(UIPinchGestureRecognizer *)pinchRecognizer
{
    UIGestureRecognizerState state = [pinchRecognizer state];

    if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
    {
        CGFloat scale = [pinchRecognizer scale];
        [pinchRecognizer.view setTransform:CGAffineTransformScale(pinchRecognizer.view.transform, scale, scale)];
        [pinchRecognizer setScale:1.0];
    }
}


- (void)handleRotate:(UIRotationGestureRecognizer *)rotationGestureRecognizer {

    UIGestureRecognizerState state = [rotationGestureRecognizer state];

    if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
    {
        CGFloat rotation = [rotationGestureRecognizer rotation];
        [rotationGestureRecognizer.view setTransform:CGAffineTransformRotate(rotationGestureRecognizer.view.transform, rotation)];
        [rotationGestureRecognizer setRotation:0];
    }
}

- (void)handlePan:(UIPanGestureRecognizer *)panRecognizer {

    UIGestureRecognizerState state = [panRecognizer state];

    if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
    {
        CGPoint translation = [panRecognizer translationInView:panRecognizer.view];
        [panRecognizer.view setTransform:CGAffineTransformTranslate(panRecognizer.view.transform, translation.x, translation.y)];
        [panRecognizer setTranslation:CGPointZero inView:panRecognizer.view];
    }
}

这就是它的样子：

- lucaslt89

0

尝试做这些...

首先在你的ViewControllers .h文件中做这些...

@interface RotationViewController : UIViewController<UIGestureRecognizerDelegate>//Add these..
{
    UIView *testView;
}

现在在您的ViewController的.m文件中执行这些操作。

- (void)viewDidLoad
{
    [super viewDidLoad];
   // Do any additional setup after loading the view.

    testView=[[UIView alloc]initWithFrame:CGRectMake(100, 100, 160, 160)];

    UIImageView * imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 160, 160)];
    [imageView setImage:[UIImage imageNamed:@"ImageName.png"]];
    [imageView setContentMode:UIViewContentModeScaleAspectFit];

    [testView addSubview:imageView];
    [self.view addSubview:testView];

    UIRotationGestureRecognizer *rotationGestureRecognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(handleRotate:)];
    [testView addGestureRecognizer:rotationGestureRecognizer];
}

-(void) handleRotate:(UIRotationGestureRecognizer *)rotationGestureRecognizer
{
    testView.transform = CGAffineTransformRotate(testView.transform, rotationGestureRecognizer.rotation);
    rotationGestureRecognizer.rotation = 0.0;
}

希望它有所帮助...

- krushnsinh

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原文链接

- Meet Doshi · Accepted Answer

首先，您需要使您的视图控制器实现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)
    }
}

希望这就是你要找的。如果有任何问题，请随时联系我。 :)