ios touchesBegan、touchesEnded、touchesMoved 用于移动 UIView

touchesBegan, touchesEnded, touchesMoved for moving UIView

提问by Matrosov Alexander

I need to drag my UIView object. I use this code, but it does not work

我需要拖动我的 UIView 对象。我使用此代码，但它不起作用

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;
        }

    }


}

采纳答案by verec

There's something a bit strange in your code.

您的代码中有些奇怪。

You ask for the location in self, some UIView which presumably contains the UILabelyou want to check. This begs the question as to why you do not add the touchesXXX to some UILabel subclass of yours.

您要求在 中的位置self，一些 UIView 大概包含UILabel您要检查的位置。这就引出了一个问题，即为什么不将 touchesXXX 添加到您的某些 UILabel 子类中。

This cancels out as you're using the label.frame which is defined in terms of its superview.bounds (your parent UIView you asked the touch location with respect to), but this doesn't make for the most straightforward way to follow what's going on.

当您使用根据其 superview.bounds 定义的 label.frame（您的父 UIView 您询问触摸位置）时，这会取消，但这并不是遵循什么的最直接方式继续。

回答by Jaybit

I would suggest using a UIPanGestureRecognizer:

我建议使用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);
}

This is just a preference of mine. To me it is a lot simpler using a gesture recognizer then using touchesBegan, touchesEnded, touchesMoved. I will use these in cases where the UIPanGestureRecognizerwill not work.

这只是我的一个偏好。对我来说，使用手势识别器比使用touchesBegan, touchesEnded,简单得多touchesMoved。我将在UIPanGestureRecognizer不起作用的情况下使用这些。

回答by Matrosov Alexander

This is work code for move UIView objects

这是移动 UIView 对象的工作代码

float oldX, oldY; BOOL dragging;

浮动 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;
        }
    }
}

回答by Nappa

With this code i could move my UIView Object anywhere. My ViewController.swift looks like this.

使用此代码，我可以将 UIView 对象移动到任何地方。我的 ViewController.swift 看起来像这样。

// 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

Hope it helps although it is another way to do it than the one mentioned in question.

希望它有所帮助，尽管它是另一种方法而不是所提到的方法。