如何使用 UIPanGestureIdentiizer 移动对象? iPhone/iPad

这里有几个 UIPanGestureRecognizer类的例子。例如，我已经阅读了 这个，我仍然不能使用它..。

在我正在处理的 nib 文件中，我有一个 UIView(图像上的白色矩形) ，我希望用这个类来拖动它:

enter image description here

在我的.m 文件中，我放置了:

- (void)setTranslation:(CGPoint)translation inView:(UIView *)view
{
NSLog(@"Test to see if this method gets executed");
}

当我在 UIView上拖动鼠标时，这个方法不会被执行:

- (void)pan:(UIPanGestureRecognizer *)gesture
{
NSLog(@"testing");
}

这个方法也不会被执行。也许我错了，但是我认为这个方法应该像 - (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event方法一样工作，我只需要放置这个方法，它就会在任何触摸时被调用。

我做错了什么？也许我需要把这个方法联系起来？如果是这样，我该怎么做？

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最佳答案

I found the tutorial Working with UIGestureRecognizers, and I think that is what I am looking for. It helped me come up with the following solution:

-(IBAction) someMethod {
UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(move:)];
[panRecognizer setMinimumNumberOfTouches:1];
[panRecognizer setMaximumNumberOfTouches:1];
[ViewMain addGestureRecognizer:panRecognizer];
[panRecognizer release];
}


-(void)move:(UIPanGestureRecognizer*)sender {
[self.view bringSubviewToFront:sender.view];
CGPoint translatedPoint = [sender translationInView:sender.view.superview];


if (sender.state == UIGestureRecognizerStateBegan) {
firstX = sender.view.center.x;
firstY = sender.view.center.y;
}




translatedPoint = CGPointMake(sender.view.center.x+translatedPoint.x, sender.view.center.y+translatedPoint.y);


[sender.view setCenter:translatedPoint];
[sender setTranslation:CGPointZero inView:sender.view];


if (sender.state == UIGestureRecognizerStateEnded) {
CGFloat velocityX = (0.2*[sender velocityInView:self.view].x);
CGFloat velocityY = (0.2*[sender velocityInView:self.view].y);


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


if (finalX < 0) {
finalX = 0;
} else if (finalX > self.view.frame.size.width) {
finalX = self.view.frame.size.width;
}


if (finalY < 50) { // to avoid status bar
finalY = 50;
} else if (finalY > self.view.frame.size.height) {
finalY = self.view.frame.size.height;
}


CGFloat animationDuration = (ABS(velocityX)*.0002)+.2;


NSLog(@"the duration is: %f", animationDuration);


[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:animationDuration];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:@selector(animationDidFinish)];
[[sender view] setCenter:CGPointMake(finalX, finalY)];
[UIView commitAnimations];
}
}
小开 
UIPanGestureRecognizer * pan1 = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(moveObject:)];
pan1.minimumNumberOfTouches = 1;
[image1 addGestureRecognizer:pan1];


-(void)moveObject:(UIPanGestureRecognizer *)pan;
{
image1.center = [pan locationInView:image1.superview];
}
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-(IBAction)Method
{
UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];
[panRecognizer setMinimumNumberOfTouches:1];
[panRecognizer setMaximumNumberOfTouches:1];
[ViewMain addGestureRecognizer:panRecognizer];
[panRecognizer release];
}
- (Void)handlePan:(UIPanGestureRecognizer *)recognizer
{


CGPoint translation = [recognizer translationInView:self.view];
recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x,
recognizer.view.center.y + translation.y);
[recognizer setTranslation:CGPointMake(0, 0) inView:self.view];


if (recognizer.state == UIGestureRecognizerStateEnded) {


CGPoint velocity = [recognizer velocityInView:self.view];
CGFloat magnitude = sqrtf((velocity.x * velocity.x) + (velocity.y * velocity.y));
CGFloat slideMult = magnitude / 200;
NSLog(@"magnitude: %f, slideMult: %f", magnitude, slideMult);


float slideFactor = 0.1 * slideMult; // Increase for more of a slide
CGPoint finalPoint = CGPointMake(recognizer.view.center.x + (velocity.x * slideFactor),
recognizer.view.center.y + (velocity.y * slideFactor));
finalPoint.x = MIN(MAX(finalPoint.x, 0), self.view.bounds.size.width);
finalPoint.y = MIN(MAX(finalPoint.y, 0), self.view.bounds.size.height);


[UIView animateWithDuration:slideFactor*2 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{
recognizer.view.center = finalPoint;
} completion:nil];


}


}
小开

The Swift 2 version:

// start detecting pan gesture
let panGestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(TTAltimeterDetailViewController.panGestureDetected(_:)))
panGestureRecognizer.minimumNumberOfTouches = 1
self.chartOverlayView.addGestureRecognizer(panGestureRecognizer)


func panGestureDetected(panGestureRecognizer: UIPanGestureRecognizer) {
print("pan gesture recognized")
}
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if ([recognizer state] == UIGestureRecognizerStateChanged)
{
CGPoint translation1 = [recognizer translationInView:main_view];
img12.center=CGPointMake(img12.center.x+translation1.x, img12.center.y+ translation1.y);
[recognizer setTranslation:CGPointMake(0, 0) inView:main_view];


recognizer.view.center=CGPointMake(recognizer.view.center.x+translation1.x, recognizer.view.center.y+ translation1.y);
}


-(void)move:(UIPanGestureRecognizer*)recognizer
{
if ([recognizer state] == UIGestureRecognizerStateChanged)
{
CGPoint translation = [recognizer translationInView:self.view];
recognizer.view.center=CGPointMake(recognizer.view.center.x+translation.x, recognizer.view.center.y+ translation.y);
[recognizer setTranslation:CGPointMake(0, 0) inView:self.view];
}
}
小开

swift 2 version of the @MS AppTech answer

func handlePan(panGest : UIPanGestureRecognizer) {
let velocity : CGPoint = panGest.velocityInView(self.view);
let magnitude : CGFloat = CGFloat(sqrtf((Float(velocity.x) * Float(velocity.x)) + (Float(velocity.y) * Float(velocity.y))));
let slideMult :CGFloat = magnitude / 200;
//NSLog(@"magnitude: %f, slideMult: %f", magnitude, slideMult);


let slideFactor : CGFloat = 0.1 * slideMult; // Increase for more of a slide
var finalPoint : CGPoint = CGPointMake(panGest.view!.center.x + (velocity.x * slideFactor),
panGest.view!.center.y + (velocity.y * slideFactor));
finalPoint.x = min(max(finalPoint.x, 0), self.view.bounds.size.width);
finalPoint.y = min(max(finalPoint.y, 0), self.view.bounds.size.height);


UIView.animateWithDuration(Double(slideFactor*2), delay: 0, options: UIViewAnimationOptions.CurveEaseOut, animations: {
panGest.view!.center = finalPoint;
}, completion: nil)
}
小开

Casting my hat into the ring a couple years later.

Will need to save the beginning center of the image view:

var panBegin: CGPoint.zero

Then update the new center using a transform:

if recognizer.state == .began {
panBegin = imageView!.center


} else if recognizer.state == .ended {
panBegin = CGPoint.zero


} else if recognizer.state == .changed {
let translation = recognizer.translation(in: view)
let panOffsetTransform = CGAffineTransform( translationX: translation.x, y: translation.y)


imageView!.center = panBegin.applying(panOffsetTransform)
}
小开

@Tono Nam's answer (accepted) in Swift 5

func someMethod() {
let panGestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(move))
panGestureRecognizer.minimumNumberOfTouches = 1
panGestureRecognizer.maximumNumberOfTouches = 1
view.addGestureRecognizer(panGestureRecognizer)
}


@objc func move(sender: UIPanGestureRecognizer) {
guard let senderView = sender.view else { return }
    

self.view.bringSubviewToFront(senderView)
var translatedPoint: CGPoint = sender.translation(in: senderView.superview)
    

if(sender.state == .began) {
let firstX = senderView.center.x
let firstY = senderView.center.y
}
    

translatedPoint = CGPoint(x: senderView.center.x + translatedPoint.x, y: senderView.center.y + translatedPoint.y)
senderView.center = translatedPoint
sender.setTranslation(.zero, in: senderView)
    

if(sender.state == .ended) {
let velocityX: CGFloat = (0.2 * sender.velocity(in: self.view).x)
let velocityY: CGFloat = (0.2 * sender.velocity(in: self.view).y)
        

var finalX: CGFloat = translatedPoint.x + velocityX
var finalY: CGFloat = translatedPoint.y + velocityY
        

if(finalX < 0) {
finalX = 0
} else if (finalX > self.view.frame.size.width) {
finalX = self.view.frame.size.width;
}
        

if (finalY < 50) { // to avoid status bar
finalY = 50;
} else if (finalY > self.view.frame.size.height) {
finalY = self.view.frame.size.height;
}
        

let animationDuration: TimeInterval = TimeInterval(abs(velocityX) * 0.0002 + 0.2)
print("the animation duration is \(animationDuration)")
        

UIView.animate(withDuration: animationDuration, delay: 0, options: .curveEaseOut) {
senderView.center = CGPoint(x: finalX, y: finalY)
} completion: { completed in
// call animationDidFinish completion handler here
}
}
}
小开

As an addition, because I spend a lot of time on this: my view (which I applied addGestureRecognizer on) was dynamically created, so I did have to fix userInteractionEnabled to true


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