的touchesBegan,touchesEnded,touchesMoved用于移动的UIView

2019-07-19 19:47发布

我要拖我的UIView对象。 我用这个代码,但它不工作

float oldX, oldY;
BOOL dragging;

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

    UITouch *touch = [[event allTouches] anyObject];
    CGPoint touchLocation = [touch locationInView:self];

    if ([[touch.view class] isSubclassOfClass:[UILabel class]]) {
        UILabel *label = (UILabel *)touch.view;
        if (CGRectContainsPoint(label.frame, touchLocation)) {
            dragging = YES;
            oldX = touchLocation.x;
            oldY = touchLocation.y;
        }
    }


}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

    dragging = NO;
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {

    UITouch *touch = [[event allTouches] anyObject];
    CGPoint touchLocation = [touch locationInView:self];

    if ([[touch.view class] isSubclassOfClass:[UILabel class]]) {
        UILabel *label = (UILabel *)touch.view;

        if (dragging) {
            CGRect frame = label.frame;
            frame.origin.x = label.frame.origin.x + touchLocation.x - oldX;
            frame.origin.y =  label.frame.origin.y + touchLocation.y - oldY;
            label.frame = frame;
        }

    }


}

Answer 1:

有什么东西有点怪在你的代码。

你问在定位self ,有的UIView的这大概包含UILabel要检查。 这引出了一个问题,为什么你不将touchesXXX添加到您的一些子类的UILabel。

这抵消了,你正在使用的是其superview.bounds来定义的(你父母的UIView你问的触摸位置相对)的label.frame,但是这不会使最直接的方式遵循什么怎么回事。



Answer 2:

我会建议使用UIPanGestureRecognizer

-(void)dragging:(UIPanGestureRecognizer *)gesture
{
    // Check if this is the first touch
    if(gesture.state == UIGestureRecognizerStateBegan)
    {
        // Store the initial touch so when we change positions we do not snap
        self.panCoord = [gesture locationInView:gesture.view];
        [self.view bringSubviewToFront:gesture.view];

    }

    CGPoint newCoord = [gesture locationInView:gesture.view];

    // Create the frame offsets to use our finger position in the view.
    float dX = newCoord.x-self.panCoord.x;
    float dY = newCoord.y-self.panCoord.y;

    gesture.view.frame = CGRectMake(gesture.view.frame.origin.x+dX,
                                    gesture.view.frame.origin.y+dY,
                                    gesture.view.frame.size.width, 
                                    gesture.view.frame.size.height);
}

这只是我的偏好。 对我来说,是使用再利用手势识别器简单得多touchesBegantouchesEndedtouchesMoved 。 我会在情况下使用这些在UIPanGestureRecognizer将无法正常工作。



Answer 3:

这是移动的UIView对象工作代码

浮oldX,oldY; BOOL拖动;

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [[event allTouches] anyObject];
    CGPoint touchLocation = [touch locationInView:touch.view];
    if ([[touch.view class] isSubclassOfClass:[UILabel class]]) {
        dragging = YES;
        oldX = touchLocation.x;
        oldY = touchLocation.y;
    }
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    dragging = NO;
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [[event allTouches] anyObject];
    CGPoint touchLocation = [touch locationInView:touch.view];    
    if ([[touch.view class] isSubclassOfClass:[UILabel class]]) {
        UILabel *label = (UILabel *)touch.view;
        if (dragging) {
            CGRect frame = label.frame;
            frame.origin.x = label.frame.origin.x + touchLocation.x - oldX;
            frame.origin.y = label.frame.origin.y + touchLocation.y - oldY;
            label.frame = frame;
        }
    }
}


Answer 4:

有了这个代码,我可以移动任何地方我UIView对象。 我ViewController.swift看起来是这样的。

// code from below

import UIKit

class ViewController: UIViewController {

    var location = CGPoint(x: 0, y: 0)

    @IBOutlet weak var Person: UIImageView!

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {

        var touch : UITouch! =  touches.first! as UITouch

        location = touch.location(in: self.view)

        Person.center = location

    }

    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {

        var touch : UITouch! =  touches.first! as UITouch

        location = touch.location(in: self.view)

        Person.center = location
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        Person.center = CGPoint(x: 160, y: 330)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


}

//ends

希望它可以帮助虽然它是另一种方式来做到这一点比在问题中提到的一个。



文章来源: touchesBegan, touchesEnded, touchesMoved for moving UIView