如何使用手势识别器阻止UIImageView在UIView之外移动？

我正在创建一个基于图像的应用程序，我希望显示的图像在我创建的UIView中旋转/移动/缩放。我在网上学习了一个关于如何实现UI手势的有用教程，我已经掌握了使用它们的诀窍，我只需要进一步了解它们背后的代码，这样我就可以在这个UIView中保留手势。代码如下：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
layoutOne = [[UIView alloc] initWithFrame:CGRectMake(95.0, 107.0, 578, 682)];
theImageView = [[UIImageView alloc] initWithFrame:[layoutOne frame]];
[theImageView setImage:image];
theImageView.userInteractionEnabled = TRUE;
[layoutOne addSubview:theImageView];
takePhoto.hidden = YES;
theImageView.clipsToBounds = YES;

UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scale:)];
[pinchRecognizer setDelegate:self];
[theImageView addGestureRecognizer:pinchRecognizer];

UIRotationGestureRecognizer *rotationRecognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotate:)];
[rotationRecognizer setDelegate:self];
[theImageView addGestureRecognizer:rotationRecognizer];

UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(move:)];
[panRecognizer setMinimumNumberOfTouches:1];
[panRecognizer setMaximumNumberOfTouches:1];
[panRecognizer setDelegate:self];
[theImageView addGestureRecognizer:panRecognizer];

UITapGestureRecognizer *deleteButton = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(delButton:)];
[deleteButton setNumberOfTapsRequired:2];
[deleteButton setDelegate:self];
[theImageView addGestureRecognizer:deleteButton];


UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapped:)];
[tapRecognizer setNumberOfTapsRequired:1];
[tapRecognizer setDelegate:self];
[tapRecognizer requireGestureRecognizerToFail:deleteButton];
[theImageView addGestureRecognizer:tapRecognizer];
[self.view addSubview:theImageView];
}

注意

UIImage *image;
UIImageView *theImageView;
UIView *layoutOne;

这些是我声明的手势识别器，下面是我指导他们完成工作的教程的另一部分：

-(void)scale:(id)sender {
NSLog(@"See a pinch gesture");
[self.view bringSubviewToFront:[(UIPinchGestureRecognizer*)sender view]];

if([(UIPinchGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) {

    lastScale = 1.0;
    return;
}

CGFloat scale = 1.0 - (lastScale - [(UIPinchGestureRecognizer*)sender scale]);

CGAffineTransform currentTransform = [(UIPinchGestureRecognizer*)sender view].transform;
CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, scale, scale);

[[(UIPinchGestureRecognizer*)sender view] setTransform:newTransform];

lastScale = [(UIPinchGestureRecognizer*)sender scale];
}

-(void)rotate:(id)sender {
    NSLog(@"See a rotate gesture");
    [self.view bringSubviewToFront:[(UIRotationGestureRecognizer*)sender view]];    

    if([(UIRotationGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) {

        lastRotation = 0.0;
        return;
    }

CGFloat rotation = 0.0 - (lastRotation - [(UIRotationGestureRecognizer*)sender rotation]);

CGAffineTransform currentTransform = [(UIPinchGestureRecognizer*)sender view].transform;
CGAffineTransform newTransform = CGAffineTransformRotate(currentTransform,rotation);

[[(UIRotationGestureRecognizer*)sender view] setTransform:newTransform];

lastRotation = [(UIRotationGestureRecognizer*)sender rotation];
}

-(void)move:(id)sender {
    NSLog(@"See a move gesture");
    [[(UITapGestureRecognizer*)sender view] layer];//removeAllAnimations];

[self.view bringSubviewToFront:[(UIPanGestureRecognizer*)sender view]];
CGPoint translatedPoint = [(UIPanGestureRecognizer*)sender translationInView:self.view];

if([(UIPanGestureRecognizer*)sender state] == UIGestureRecognizerStateBegan) {

    firstX = [[sender view] center].x;
    firstY = [[sender view] center].y;


}


translatedPoint = CGPointMake(firstX+translatedPoint.x, firstY+translatedPoint.y);

[[sender view] setCenter:translatedPoint];
if([(UIPanGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) {

    CGFloat finalX = translatedPoint.x + (.35*[(UIPanGestureRecognizer*)sender velocityInView:self.view].x);
    CGFloat finalY = translatedPoint.y + (.35*[(UIPanGestureRecognizer*)sender velocityInView:self.view].y);

    if(UIDeviceOrientationIsPortrait([[UIDevice currentDevice] orientation])) {

        if(finalX < 0) {

            finalX = 0;
        }

        else if(finalX > 768) {

            finalX = 768;
        }

        if(finalY < 0) {

            finalY = 0;
        }

        else if(finalY > 1024) {

            finalY = 1024;
        }
    }

    else {

        if(finalX < 0) {

            finalX = 0;
        }

        else if(finalX > 1024) {

            finalX = 768;
        }

        if(finalY < 0) {

            finalY = 0;
        }

        else if(finalY > 768) {

            finalY = 1024;
        }
    }
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:.35];
    [UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
    [[sender view] setCenter:CGPointMake(finalX, finalY)];
    [UIView commitAnimations];
}

}

-（无效）刻度：（id）发送方{
NSLog（@“看到一个捏手势”）；
[self.view将subviewTofront:[（uipinchgestrerecognizer*）发件人视图]]；
if（[（UIPinchGestureRecognizer*）发送方状态]==UIGestureRecognizerStateEnded）{
lastScale=1.0；
返回；
}
CGFloat scale=1.0-（lastScale-[（uipinchgestrerecognizer*）发送方比例]；
CGAffineTransform currentTransform=[（UIPinchGetureRecognitizer*）发件人视图]。转换；
CGAffineTransform newTransform=CGAffineTransformScale（当前变换，缩放，缩放）；
[[（UIPinchGestureRecognitor*）发送方视图]设置转换：新转换]；
lastScale=[（UIPinchGestureRecognizer*）发送方比例]；
}
-（无效）旋转：（id）发送器{
NSLog（@“看到旋转手势”）；
[self.view将subview带到前台：[（UIRotationGestureRecognitor*）发件人视图]；
if（[（UIRotationGestureRecognizer*）发送方状态]==UIGestureRecognizerStateEnded）{
最后旋转=0.0；
返回；
}
CGFloat rotation=0.0-（lastRotation-[（UIRotationGestureRecognitor*）发送方旋转]；
CGAffineTransform currentTransform=[（UIPinchGetureRecognitizer*）发件人视图]。转换；
CGAffineTransform newTransform=CGAffineTransformRotate（当前变换，旋转）；
[[（UIRotationGestureRecognitor*）发送方视图]设置转换：新转换]；
lastRotation=[（UIRotationGestureRecognitor*）发送方旋转]；
}
-（无效）移动：（id）发件人{
NSLog（@“看到移动手势”）；
[[（UITapGestureRecognitizer*）发送方视图]层]；//删除配置]；
[self.view将subviewTofront:[（UIPanGestureRecognizer*）发件人视图]]；
CGPoint translatedPoint=[（UIPangestureRecognitor*）发送方翻译视图：self.view]；
if（[（UIPangestureRecognitizer*）发送方状态]==UIgestureRecognitizerStateStart）{
firstX=[[sender view]center].x；
firstY=[[sender view]center].y；
}
translatedPoint=CGPointMake（firstX+translatedPoint.x，firstY+translatedPoint.y）；
[[sender view]设置中心：translatedPoint]；
if（[（UIPangestureRecognitizer*）发送方状态]==UIgestureRecognitizerStateEnded）{
CGFloat finalX=translatedPoint.x+（.35*[（UIPangestureRecognitizer*）发送方速度视图：self.view].x）；
CGFloat finalY=translatedPoint.y+（.35*[（UIPangestureRecognitizer*）发送方速度视图：self.view].y）；
if（UIDeviceOrientationSportRait（[[UIDevice currentDevice]方向]）{
如果（finalX<0）{
finalX=0；
}
否则，如果（最终结果>768）{
finalX=768；
}
如果（最终<0）{
finalY=0；
}
否则，如果（最终>1024）{
最终=1024；
}
}
否则{
如果（finalX<0）{
finalX=0；
}
否则如果（finalX>1024）{
finalX=768；
}
如果（最终<0）{
finalY=0；
}
否则，如果（最终>768）{
最终=1024；
}
}
[UIView beginAnimations:nil上下文：NULL]；
[UIView setAnimationDuration:.35]；
[UIView设置动画曲线：UIViewAnimationCurveEaseOut]；
[[sender view]设置中心：CGPointMake（finalX，finalY）]；
[UIView委员会]；
}
}

---

抱歉，代码太长了，我只是想确保您完全理解我要实现的目标。我想更好地理解主要在

-（void）move:（id）sender

中进行的数学运算，这样我就可以阻止UIImage/UIImageView移动到我创建的UI子视图（layoutOne）之外。如果你能帮助我，我将不胜感激！谢谢。

我用上面的方法解决了这个问题。一旦我知道我需要做什么，这真的很容易。如果您在自己之上使用此方法，则只需确保您在本例中使用的

UIView

名为

layoutOne

。在

移动：

，

旋转：

，

缩放：

方法中，您需要添加到

layoutOne.clipstobunds=YES确保它不在任何
if
、
else if
、
else
语句中。这将使您希望与之交互的图像不会移动到
ui视图
之外，相反，如果它触及视图的边界，图像的这些部分将不会出现。傻瓜