iOS 如何使用 touchesMoved 移动两个图像？

Posted 2023-03-07

【中文标题】iOS 如何使用 touchesMoved 移动两个图像？

【英文标题】：iOS How to use touchesMoved to move two images?

【发布时间】：2012-07-02 20:07:01

【问题描述】：

我有两个不同的UIImages。 我想允许用户将这些图像单独移动到UIView 上。 我怎么能这样做？

IBOutlet UIImageView *image01;
IBOutlet UIImageView *image02;

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
    UITouch *touch = [touches anyObject];
    CGPoint location = [touch locationInView:touch.view];

【问题讨论】：

能否在定义CGPoint location = 之后添加这一行：imageToBeMoved.center = location 并查看它是否有效。

【参考方案1】：

我不确定我是否理解这个问题。您可以使用标准平移手势识别器，每个UIImageView 一个，例如：

UIPanGestureRecognizer *pan1 = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanImage:)];
image01.userInteractionEnabled = YES;
[self.image01 addGestureRecognizer:pan1];

UIPanGestureRecognizer *pan2 = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanImage:)];
image02.userInteractionEnabled = YES;
[self.image02 addGestureRecognizer:pan2];

和

- (void)handlePanImage:(UIPanGestureRecognizer *)sender

    static CGPoint originalCenter;

    if (sender.state == UIGestureRecognizerStateBegan)
    
        originalCenter = sender.view.center;
        sender.view.alpha = 0.8;
        [sender.view.superview bringSubviewToFront:sender.view];
    
    else if (sender.state == UIGestureRecognizerStateChanged)
    
        CGPoint translation = [sender translationInView:self.view];

        sender.view.center = CGPointMake(originalCenter.x + translation.x, originalCenter.y + translation.y);
    
    else if (sender.state == UIGestureRecognizerStateEnded || sender.state == UIGestureRecognizerStateCancelled || sender.state == UIGestureRecognizerStateFailed)
    
        // do whatever post dragging you want, e.g.
        // snap the piece into place

        [UIView animateWithDuration:0.2 animations:^
            CGPoint center = sender.view.center;
            center.x = round(center.x / 50.0) * 50.0;
            center.y = round(center.y / 50.0) * 50.0;
            sender.view.center = center;
            sender.view.alpha  = 1.0;
        ];
    

或者您可以在他们的超级视图上创建一个手势识别器，然后使用 CGRectContainsPoint 来查看您的起始 locationInView 是否在您的两个 UIImageView 之一的框架内，然后继续为适当的一个设置动画。

例如，在您的视图控制器中，您可以创建一个手势识别器：

UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanSuper:)];
[self.view addGestureRecognizer:pan];

并且处理程序可能看起来像（如果需要，您也可以将其实现为自定义手势识别器）：

- (void)handlePanSuper:(UIPanGestureRecognizer *)sender

    static UIImageView *viewToMove;
    static CGPoint      originalCenter;

    if (sender.state == UIGestureRecognizerStateBegan)
    
        CGPoint location = [sender locationInView:self.view];

        if (CGRectContainsPoint(self.image01.frame, location))
        
            viewToMove = image01;
            originalCenter = viewToMove.center;
         
        else if (CGRectContainsPoint(self.image02.frame, location))
        
            viewToMove = image02;
            originalCenter = viewToMove.center;
        
        else
        
            viewToMove = nil;
        

        if (viewToMove)
        
            viewToMove.alpha = 0.8;
            [viewToMove.superview bringSubviewToFront:viewToMove];
        
    
    else if (sender.state == UIGestureRecognizerStateChanged && viewToMove != nil)
    
        CGPoint translation = [sender translationInView:self.view];

        viewToMove.center = CGPointMake(originalCenter.x + translation.x, originalCenter.y + translation.y);
    
    else if ((sender.state == UIGestureRecognizerStateEnded || 
              sender.state == UIGestureRecognizerStateFailed || 
              sender.state == UIGestureRecognizerStateCancelled) && viewToMove != nil)
    
        // do whatever post dragging you want, e.g.
        // snap the piece into place

        [UIView animateWithDuration:0.2 animations:^
            CGPoint center = viewToMove.center;
            center.x = round(center.x / 50.0) * 50.0;
            center.y = round(center.y / 50.0) * 50.0;
            viewToMove.center = center;
            viewToMove.alpha  = 1.0;
        ];

        viewToMove = nil;
    

如果我误解了你的问题，请告诉我。

【讨论】：

没关系，但我正在为孩子们开发一款益智游戏，让他们一起收集图像碎片。对不起我的英语。

@YaserAlNamshan 没问题。令我震惊的是，上述任何一种技术都应该可以正常工作。如果您不想这样做，则无需对识别器进行子类化和使用。唯一的问题是您是想要在每张图像上使用手势识别器，还是只需要一个手势识别器。顺便说一句，我已经用各种增强的示例更新了我的代码示例，例如拖动时减少 alpha，移动到前面以免被其他图像遮挡，最后将片段对齐等。只是给你一些想法。

谢谢罗伯特，我想我会使用这种技术:)