ios - touchesBegan, touchesEnded, touchesMoved 用于移动 UIView

Question

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;
        }

    }


}

Answer 1

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);
}

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

Answer 2

这是移动 UIView 对象的工作代码

浮动旧X，旧Y；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 3

你的代码有些奇怪。

您询问位置self，一些 UIView 大概包含UILabel您要检查的内容。这就引出了一个问题，即为什么您不将 touchesXXX 添加到您的某些 UILabel 子类中。

当您使用根据其 superview.bounds 定义的 label.frame （您询问触摸位置的父 UIView）时，这会抵消，但这并不是最直接的方式来遵循什么是继续。

Answer 4

使用此代码，我可以将我的 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

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。